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09.d1 Engineering Updates 12-17-2024
City of Scandia
Engineering Updates 12/17/2024
Engineering Italics = Old information
Red = Projects removed from Engineering Update
• 2024 Street Improvement Project
• 2025 Street Improvement Project
➢ Anticipated project schedule is as follows:
o Approve Plans & specifications/Authorize Ad for Bid – January 21, 2025.
o Bid Opening – February 19, 2025.
o Consider Contract Award at City Council Meeting – March 18, 2025.
➢ Geotechnical report was received on December 11, 2024.
➢ Both CMSCWD and CLFLWD were contacted regarding potential “add-on” projects that
could be implemented as part of the 2025 Street Improvement Project. Neither watershed
identified any potential projects within our scope.
➢ CMSCWD will not be requiring any permits for this project. Permit application for CLFLWD
will be submitted later this month.
• Tii Gavo Development Phase II
➢ Watershed permit has been obtained and grading work began on Tuesday July 11th. BMI will have staff on site
for public infrastructure inspections.
➢ The bituminous base layer was paved on 8/17/2023.
➢ Aggregate shouldering was completed on 8/30/2023.
➢ Restoration Punchlist will be created in early April 2024.
➢ Hand auger borings have been scheduled for each of the non-functioning basins along with a grain analysis and
hydrometer testing.
➢ Once this revised work has been completed, an updated restoration punchlist will be created and sent to the
Contractor.
➢ A request to reduce the Letter of Credit for this development has been included as a separate agenda item.
➢ Plowe Engineering is still waiting to receive the hand auger boring results.
➢ Braun is still completing lab tests on the borings samples collected in June. Once completed, Plowe will begin
corrective design in coordination with CMSCWD.
➢ Plowe is currently working on the corrective design for the basins on-site, in coordination with the watershed,
and hoping to have an approved plan within the next few weeks.
➢ Weather permitting, these corrections will take place this year.
➢ Corrective design has been completed and is being reviewed by the Contractor. The finalized plans will then be
sent to the CMSCWD and City for review during the week of November 11th – 15th.
➢ Corrective designs were submitted to the City and CMSCWD on Thursday, November 14th.
➢ The plans did not fully encompass the design aspects requested by CMSCWD to construct
fully functioning water treatment basins. CMSCWD has since provided additional comments
that are being implemented.
• 2024 Tennis Court Reconstruction Project
➢ Project Schedule is as follows:
o Approve Plans & Specifications/Authorize ad for Bid – June 18, 2024.
o Bid Opening – July 10, 2024.
o Consider Contract Award at City Council Meeting – July 16, 2024.
➢ Geotechnical report was received on March 26th, 2024.
o The report soil borings determined that Barton Johson and Community Center Tennis Courts should
both be reconstructed with new bases and pavement. Proposed sections have been discussed with
City Staff.
➢ Wetland Delineations were collected on Thursday April 11th.
o Plan and permitting updates will be completed once delineations have been reviewed and
discussed with City Staff.
➢ Plans and specifications have been completed. City comments were received and implemented throughout this
design process.
➢ Request to approve plans, specifications and authorize ad for bid has been included as a separate agenda item.
➢ Bids for the 2024 Tennis Court Reconstruction Project were opened on Wednesday, July 10th, at 9:00am.
➢ The City Council awarded the Base Bid + Alternate 1 to Veit & Company, Inc. at the August 7 th Council workshop.
➢ Change Order No. 1 has been put together and sent to Veit & Company on August 12th.
➢ A preconstruction meeting has been scheduled for Tuesday August 20th at 10am.
➢ Construction will begin after September 9th.
➢ Tree removal began by the City on Monday September 9th, with the Contractor beginning removal work on
September 10th.
➢ The Contractor stockpiled, and plans to test, the existing aggregate base layer to determine whether it can be
re-used as base material. If passing, they will re-use what material they can, and supplement with new class 5
aggregate for the additional tennis court.
➢ Change Order No. 2 has been put together and sent to Veit & Company on September 11th for unit pricing.
Change Order No. 2 includes a price adjustment for removing unforeseen bituminous pavement below the
aggregate base layer (this was not captured by soil borings due to the sporadic nature of the bituminous
pavement).
o This Change Order has been attached to the end of this report (unit price not yet received from
Veit).
➢ Fence posts have been installed, with concrete and pavement work to be completed still this month.
➢ Minor basin corrective work will take place over the next week. Drain tile will be corrected to promote drainage,
and additional filter media will be added to the basin.
➢ Contractor’s Request for Payment No. 1 has been included as a separate agenda item.
➢ The contractor poured the concrete maintenance strip on October 15th.
➢ Paving was completed in 2 lifts. The first lift was placed on October 21st, and the second on October 24th.
➢ Corrective concrete work was completed on October 29th.
➢ Contractor’s Request for Payment No. 2 has been included as a separate agenda item.
• Floodplain Risk Assessment
➢ Watershed District has received notification from the MPCA they did not receive the grant that was applied for.
➢ CMSCWD Board is considering allocating funding for the Risk Assessment in 2024 at their 2024 CMSCWD Budget
Workshop.
➢ The draft 2024 CMSCWD budget currently includes funding to address model data gaps for the Big Marine Lake
outlet, Carnelian Channel, and Carnelian Creek flowages. This is the first step in a multi-year process to
complete the Floodplain Risk Assessment.
➢ Application #3 was not awarded.
➢ Application #4 is due on December 14th, 2023.
➢ The 2024 CMSCWD budget includes funding to address model data gaps for the Big Marine Lake outlet,
Carnelian Channel, and Carnelian Creek flowages. This is the first step in a multi-year process to complete the
Floodplain Risk Assessment.
➢ Application #4 was not funded.
➢ Application #5 is being prepared for submittal on April 30th, 2024.
➢ Application #5 has been prepared and submitted for the MPCA-Small Communities Planning for SWC Resilience
on April 30th, 2024.
➢ When the CMSCWD begins their 2025 budgeting process in July, the board will consider funding the next steps in
the planning process, with or without a grant.
➢ A survey of the Big Marine Outlet and channel has already been completed, assessing the conditions of the
culverts, and evaluating the existing channel profile. This was an important step to improve the watershed’s
model for planning and future maintenance.
➢ A location map for this channel has been provided at the end of this report.
➢ No Update on Application #5 as of July 10th, a verbal update will be brought to council on July 16th.
➢ Application #5 has been selected and the CMSCWD will receive a grant in the amount of $50,000. This will be
used to supplement the funds that CMSCWD has already allocated for this assessment in their 2025 draft
budget.
➢ CMSCWD held a public budget hearing on 9/25/2024.
➢ CMSCWD has approved to enter into an agreement with the MPCA to complete this work. Modeling has begun,
and the watershed plans to reach out to the City in November to schedule an initial input meeting.
➢ Modeling work has begun, and post modeling engagement meetings with nearby cities will be scheduled in
November.
➢ The engagement plan for this project is as follows:
o First Meeting: Late January/early February: One-on-one meeting with
City/Township staff to review initial flood risk maps and identify hazards.
o Second Meeting: Late March/April: Special workshop with each City/Township
board to share flood hazard risk and vulnerability maps and discuss possible
resiliency improvements.
o Third Meeting: Date TBD: Draft results meeting to share with City/Town council
and community members.
➢ CMSCWD is also coordinating with CLFLWD to host a coordinated input meeting with
Washington County and State Agencies.
• Bliss Drainfield System
➢ The final permit has been issued. The assumption is that we’ll end up on Track 2, with required system
improvements due to the nitrate issue. Only thing that needs to take place in the next 6 months (February 28,
2022) is for new flow meters to be installed at the system, something we’ll begin working on. At the one year
mark (September 1, 2022), we’ll need to have a Facility Evaluation Report drafted to summarize the system’s
ability or inability to meet the nitrate limit.
➢ New flow meters were installed by Public Works at the beginning of 2022 and specific flows to the three
drainfield cells is now being monitored. Some additional nitrate testing was also performed in August 2022 to
provide additional data points and to get an idea of how much nutrient removal is currently taking place
through the sand filters.
➢ As of September 1, 2022, the Facility Evaluation Report has been sent to the MPCA. We await their review, but
based on the monitoring well samples taken throughout the last year it appears we’ll be on Track 2, with
improvements to the system needed to deal with the nitrate issue. Assuming this is the case, the next step will
be to complete a full Facility Plan by August of 2023 which evaluates the facility and its performance as a whole
and provides options/recommendations for improvements to be made. This is required by Track 2 but is also the
next step in obtaining PFA funding for the project.
➢ We met with MPCA on December 16, 2022 to discuss funding options and laid out a schedule to complete a
facility plan and apply for Point Source Implementation Grant (PSIG) funding.
➢ City Council authorized work to complete the facility plan on January 4, 2023. Facility plan to be submitted by
March 3, 2023. Also, Council authorized BMI to complete permit documents for permit modification due to
added treatment for nitrate removal.
➢ Testified at the Capitol on Wednesday, March 1, 2023 requesting funding for the Bliss Wastewater Treatment
Facility.
➢ Facility plan has been submitted for the City of Scandia’s Bliss Wastewater Treatment Facility along with and IUP
request and PPL application to the Minnesota Public Facilities Authority on Friday, March 3, 2023. As of June 22,
the MPCA has issued preliminary approval of this facility plan.
➢ PSIG Funding application was submitted at the end of July (2023). Received follow-up questions from the MPCA
and responses were sent at the end of August (2023).
➢ City review period for draft MPCA SDS permit ended on 4/5; the public comment period has begun and will
continue through 6/17.
➢ Initial review comments have been received from the MPCA and responses returned.
➢ Depending on multiple other factors, we’ll likely be re-applying for PSIG (Point Source Implementation Grant) by
the end of July (deadline), as if obtained this could fund up to 80% of project.
➢ Plans and specifications were submitted for MPCA review at the end of March.
➢ Response has been received on the environmental review of the project and the DNR has identified the site as
potential nesting land for Blanding’s Turtles. We are working to address the requirements associated with this
in addition to the other revisions.
➢ Comments from the MPCA have been addressed and have been certified by the MPCA as of the end of June.
➢ As of the end of June, the new SDS Permit for the Scandia WW system has been issued. This means that
groundwater monitoring well GW 008 now needs to be sealed within 180 days, as that is part of the permit
requirements.
➢ Bolton and Menk re-applied for PSIG at the end of July. The PFA has indicated that it’s unlikely that Scandia will
be in the fundable range for 2025 given the lack of a bonding bill.
➢ A meeting was conducted between City Staff, Bolton and Menk, and the MPCA on August 14th regarding lack of
project funding.
➢ Per that discussion, BMI has drafted a letter to be formally sent by the City to the MPCA which explains the
situation and all steps that have been taken (and are continuing to be taken) to try and obtain funding to
complete this required project. The letter also requested a modification to the permit schedule which would
extend the timeline to construct from 2025 to 2026 with the assumption that a bonding bill will be passed which
funds PSIG and allows Scandia a realistic path to obtaining this funding. This letter has been attached to the end
of this report for the Council’s review.
➢ The MPCA appears to be open to this process as a viable path forward. Ultimately if this is approved, we will re-
apply for both the CWRF and PSIG programs in 2025 with the goal of being funded for construction in 2026.
• Bliss Addition Stormwater Planning
➢ Watershed still working toward 90% plans based on City Staff input received in November 2022.
➢ City and Watershed have completed the MOU.
➢ Watershed/Consultants redesigning project practices after a final utility meet locate identified previously un -
marked conflicts.
➢ Due to delays caused by utilities not marked on the initial locate, the CMSCWD will delay construction to
2024. Upon completion of the final plans, submittals will be prepared to the City for their review. CMSCWD
anticipates soliciting bids in October 2023.
➢ Revised plans were submitted to the City and review comments were sent back to the Watershed District on
January 5, 2024.
➢ Bid Opening was held on April 2nd, 2024 (Abstract of Bid Results at the end of this update).
➢ Council chose to accept the Base Bid for this Project at the April 16th Council Meeting, and award the project to
the lowest bidder, Dresel Contracting, Inc.
➢ A preconstruction meeting was held on Tuesday June 25th with the Contractor, EOR, City Staff and Bolton &
Menk.
➢ Tree removal will take place in July, with the remainder of the project taking place during September to meet the
substantial completion date of September 30th.
➢ Private utility relocation and tree removals were completed during July.
➢ The remaining construction is still scheduled to be completed in September.
➢ The Contractor has been completing construction of BMPs the week of September 9th – September 13th.
➢ Anticipated project completion is the week of September 23rd – 27th.
➢ A site walkthrough was completed by EOR and the CMSCWD to develop a project punchlist.
➢ The punchlist contains items to correct basin grading as well as turf restoration.
➢ The punchlist is being reviewed and will be sent out the week of October 7th – 11th.
➢ All punchlist work was completed on October 28th.
➢ A site walkthrough was conducted with the MPCA as well on October 28th.
o The MPCA requested the “owner” as listed on the permit needed to be updated from EOR to
CMSCWD. This has been completed and submitted to the MPCA.
➢ Pay Application #2 is being reviewed by EOR and CMSCWD.
➢ Final project closeout is anticipated for the December or January Board meeting pending receipt of final
documentation.
• Highway 243 Osceola Bridge
➢ Project website: http://www.dot.state.mn.us/metro/projects/hwy243osceola/index.html
➢ Public Meeting scheduled for May 10, 2023, 5:00pm-7:00pm at the Osceola Village Board Room
➢ Schedule:
o Environmental documentation and preliminary design: 2022 through 2024
o Final design: 2024 through 2026
o Anticipated construction: 2027 through 2028
• The bridge is anticipated to be closed sometime in 2027 through 2028. The duration of this
closure is being considered during alternative detour evaluations.
o Restoration and project completion in 2029.
➢ Project website has been updated with a location plan showing the extents of the work. The project will span the
distance between TH 95 and TH 35.
➢ Traffic Impacts are currently under review, and potential detour plans are being developed.
o See the project website for up-to-date figures.
Denise Workcuff Dmitry Tomasevich
Communications and Engagement Project manager
denise.workcuff@state.mn.us dmitry.tomasevich@state.mn.us
651-775-0025 651-245-4406
➢ The Environmental Assessment Worksheet is now available for public review and
comments.
o All comments must be submitted via mail, email, or phone to Dmitry
Tomasevich by December 26th.
o A copy of the EAW has been included at the end of this monthly update.
• Highway 8 Study (Chisago to Taylors Falls)
➢ Project website: https://talk.dot.state.mn.us/hwy-8-chisago-taylorsfalls
o Comments and questions can be submitted on the project website.
➢ Schedule:
o August 2024 through December 2024
• Analyze existing conditions and engage stakeholders.
o November 2024 through June 2025
• Develop and evaluate ideas for improvements with stakeholders and public involvement.
o June 2024 through October 2025
• Finalize study recommendations.
o 2032
• Construction (pavement resurfacing).
• Gateway Trail / County Road 52
➢ Survey update
o Topo survey was completed on November 7th, 2023.
➢ Soil Boring update
o AET submitted the lowest bid at $21,382.00 to perform this work and had the soonest drill rig
availability.
o AET has been authorized to complete soil boring and hand auger boring work on 11/10/2023.
o Soil Borings are scheduled to be completed within 8-10 weeks, with a report coming a few weeks
after completion of field work (Braun was at least a month behind this schedule and came in at
$24,735.00). Hand Auger Borings in off street locations will be completed earlier prior to snowfall.
o AET has been instructed not to begin any work on site until after December 19th. Once approval
has been received, AET will begin hand auger borings (HABs) and then drill rig soil borings (SBs) a
few weeks after.
➢ AET began collecting hand auger borings (HABs) from December 22nd - 26th, and soil borings on December 26th -
29th.
➢ A Geotechnical report is anticipated to be received the week of 3/18 - 3/22.
➢ Figures/layouts are being created to discuss with City staff on 3/19.
➢ DNR comments have been received and are being implemented into the figures/layouts.
➢ County comments have been received and are being implemented into design for discussion at the June monthly
design review meeting.
➢ The next design review meeting with City Staff, County and the DNR is scheduled for Tuesday, June 18th at
1:00pm.
➢ Our anticipated project design timeline is as follows:
o 30% Plans in August
o 60% Plans in September
o 90% Plans in November
o County ROW/Easement acquisition from November 2024-November 2025
➢ 30% Plans have been compiled to be discussed with City Staff, Washington County, and the DNR at the August
20th monthly meeting.
➢ 60% Plans have been compiled and discussed at our monthly meeting with City Staff, Washington County, and
the DNR on September 17th.
➢ 90% Plans are scheduled to be complete prior to the November 19th meeting with City Staff, Washington County,
and the DNR.
➢ A draft bid package is being compiled and will be sent to the City, Washington County, and the DNR prior to our
monthly meeting on Tuesday November 19th.
➢ This project will not be bid until November 2025 with construction to follow the summer of 2026. This allows the
County time to work through land acquisitions required to complete the project.
➢ 90% Plans have been completed, and remaining project items are planned to be discussed
on December 17th at our monthly meeting with City Staff, Washington County, and the
DNR.
➢ Additional easement acquisition and permitting will take place in 2025.
Highway 243 Osceola
Bridge Project
Environmental Assessment/Environmental
Assessment Worksheet
November 2024
MnDOT SP 1311-06 and WisDOT Project ID 8417-00-76
ii
ENVIRONMENTAL ASSESSMENT/ENVIRONMENTAL
ASSESSMENT WORKSHEET
Trunk Highway (Hwy) 243
Minnesota State Project (SP) 1311-06 and Wisconsin Project ID 8417-00-76
Project Name: Hwy 243 Osceola Bridge Project
From Minnesota Highway 95 (MN-95) in Minnesota to Wisconsin Highway 35 (WIS-35) in Wisconsin
City(ies): Franconia Township, Minnesota and Village of Osceola, Wisconsin
County(ies): Chisago in Minnesota, Polk in Wisconsin
Section(s), Township(s), Range(s): Sec. 27, 28, Twp. 33, R 19
Submitted pursuant to 42 U.S.C. 4332, MN Statutes Chapter 116D, and WI Statute 1.11
By the
U.S. Department of Transportation Federal Highway Administration and
Minnesota Department of Transportation (MnDOT)
for
Replacement of the Hwy 243 Bridge over the St. Croix National Scenic Riverway (MnDOT Bridge No. 6347,
Wisconsin DOT (WisDOT) Bridge No. B-48-224) connecting Franconia Township, Minnesota to the Village of
Osceola, Wisconsin. Reconstruction of an approximately 0.5-mile segment of Hwy 243 and construction of a
stormwater pond.
Contacts:
FHWA: Joe Campbell
Bridge Engineer
Minnesota Division
180 East Fifth Street, Suite 930
St. Paul, MN 55101
(651) 291-6121
MnDOT: Dmitry Tomasevich
East Area Project Manager
Metro District
1500 County Road B2 W
Roseville, MN 55113
(651) 245-4406
WisDOT: Marc Bowker
Northwest Region Project Manager
718 W Clairemont Avenue
Eau Claire, WI 54701
(715) 635-4975
iii
Recommended for approval by:
Sheila Kauppi Digitally signed by Sheila Kauppi
Date: 2024.11.14 12:42:51 -06'00'
___________________________________________________________
MnDOT District Engineer Date
___________________________________________________________
WisDOT Region Director Date
____________________________
WisDOT Region Director
11/14/2024
Approved by:
___________________________________________________________
MnDOT Chief Environmental Officer Date
Marni Karnowski Digitally signed by Marni Karnowski
Date: 2024.11.14 16:16:56 -06'00'
___________________________________________________________
WisDOT Bureau of Technical Services Director Date
________________________
WisDOT Bureau of Technical
11/14/2024
Approved by:
___________________________________________________________
FHWA Project Development Engineer Date
Digitally signed by WILLIAM R
LOHR
Date: 2024.11.18 08:15:11 -06'00'
This document is available in alternative formats to individuals with disabilities by calling the Minnesota Relay
Service at 1-800-627-3529.
Hwy 243 Osceola Bridge Project | Environmental Assessment/Environmental Assessment Worksheet
iv
Figure 0-1. State Location Map
Hwy 243 Osceola Bridge Project | Environmental Assessment/Environmental Assessment Worksheet
v
Figure 0-2. Project Location Map
Hwy 243 Osceola Bridge Project | Environmental Assessment/Environmental Assessment Worksheet
vi
Table of Contents
ENVIRONMENTAL ASSESSMENT/ENVIRONMENTAL ASSESSMENT WORKSHEET ................................... II
TABLE OF CONTENTS .............................................................................................................................. VI
LIST OF TABLES ...................................................................................................................................... IX
LIST OF FIGURES .................................................................................................................................... IX
LIST OF APPENDICES ................................................................................................................................ X
LIST OF ACRONYMS ................................................................................................................................ XI
EXECUTIVE SUMMARY ...................................................................................................................... XIII
PROJECT BACKGROUND ........................................................................................................................ XIII
DOCUMENT PURPOSE .......................................................................................................................... XIII
PROJECT PURPOSE AND NEED ................................................................................................................ XIII
ALTERNATIVES ..................................................................................................................................... XIV
PREFERRED ALTERNATIVE ....................................................................................................................... XV
ENVIRONMENTAL COMMITMENTS .......................................................................................................... XVI
OPPORTUNITIES FOR PUBLIC COMMENT .................................................................................................. XVI
1. REPORT PURPOSE...................................................................................................................... 1
2. PURPOSE AND NEED FOR PROJECT ............................................................................................ 2
2.1 PRIMARY NEED: BRIDGE CONDITION ................................................................................................... 2
2.2 SECONDARY NEED: WALKABILITY/BIKEABILITY ...................................................................................... 5
2.3 ADDITIONAL CONSIDERATIONS ........................................................................................................... 8
2.3.1 Maintenance of Traffic During Construction ................................................................................ 8
2.3.2 Osceola Landing ........................................................................................................................... 8
2.3.3 Stormwater Management .......................................................................................................... 10
2.3.4 Regulatory Requirements ........................................................................................................... 10
2.3.5 Ecological Connectivity ............................................................................................................... 12
3. ALTERNATIVES ........................................................................................................................ 15
3.1 ALTERNATIVES CONSIDERED BUT REJECTED ........................................................................................ 16
3.1.1 Build Concept A: Rehabilitate existing bridge. Replace deck and superstructure. Re-use existing
piers. ...................................................................................................................................................... 16
3.1.2 Build Concept F: New Hwy 243 Bridge on new alignment between MN-95 and WIS-35 .................. 17
3.1.3 Build Concept E: New Hwy 243 Bridge along 2nd Avenue alignment in WI ....................................... 17
3.1.4 Build Concept G: Tunnel crossing under St. Croix River along existing Hwy 243 alignment ............. 17
3.1.5 Build Alternative C: New Hwy 243 Bridge on north side of existing structure .................................. 18
3.1.6 Build Alternative D: New Hwy 243 Bridge on south side of existing structure .................................. 19
3.2 ALTERNATIVES UNDER CONSIDERATION, INCLUDING THE “NO BUILD” ALTERNATIVE ................................. 20
3.2.1 No Build Alternative ........................................................................................................................... 20
3.2.2 Build Alternative B: New Hwy 243 Bridge on existing alignment ...................................................... 20
3.3 BENEFIT COST ANALYSIS ................................................................................................................. 21
3.4 BRIDGE TYPE STUDY ....................................................................................................................... 21
Hwy 243 Osceola Bridge Project | Environmental Assessment/Environmental Assessment Worksheet
vii
4. SOCIAL, ECONOMIC AND ENVIRONMENTAL IMPACTS ............................................................. 24
4.1 ENVIRONMENTAL ASSESSMENT WORKSHEET ...................................................................................... 24
4.1.1 Project Title ........................................................................................................................................ 24
4.1.2 Proposer ............................................................................................................................................. 24
4.1.3 Responsible Governmental Unit (RGU) .............................................................................................. 25
4.1.4 Reason for EAW Preparation ............................................................................................................. 25
4.1.5 Project Location ................................................................................................................................. 25
4.1.6 Project Description ...................................................................................................................... 27
4.1.7 Climate Adaptation and Resilience ............................................................................................. 31
4.1.8 Cover Types ........................................................................................................................................ 38
4.1.9 Permits and Approvals Required ....................................................................................................... 42
4.1.10 Land Use .......................................................................................................................................... 44
4.1.11 Geology, Soils, and Topography/Land Forms ............................................................................. 49
4.1.12 Water Resources .............................................................................................................................. 53
4.1.13 Contamination/Hazardous Materials and Wastes .......................................................................... 71
4.1.14 Fish, Wildlife, Plant Communities, and Sensitive Ecological Resources (Rare Features) ............. 75
4.1.15 Historic Properties ........................................................................................................................... 94
4.1.16 Visual ............................................................................................................................................... 98
4.1.17 Air .................................................................................................................................................. 104
4.1.18 Greenhouse Gas (GHG) Emissions/Carbon Footprint ............................................................... 111
4.1.19 Noise .............................................................................................................................................. 114
4.1.20 Transportation ............................................................................................................................... 117
4.1.21 Cumulative Potential Effects ......................................................................................................... 120
4.1.22 Other Potential Environmental Effects .......................................................................................... 126
4.1.23 RGU CERTIFICATION ...................................................................................................................... 127
4.2 ADDITIONAL FEDERAL ISSUES ......................................................................................................... 128
4.2.1 Social Impacts .................................................................................................................................. 128
4.2.2 Considerations Relating to Pedestrians and Bicyclists .................................................................... 130
4.2.3 Environmental Justice ...................................................................................................................... 130
4.2.4 Economics ........................................................................................................................................ 133
4.2.5 Relocation ........................................................................................................................................ 133
4.2.6 Right of Way .................................................................................................................................... 133
4.2.7 Section 4(f) of the USDOT Act of 1966 ............................................................................................. 133
4.2.8 Section 6(f)/Land and Water Conservation Fund Act ...................................................................... 141
4.2.9 Noise ................................................................................................................................................ 141
4.2.10 Farmland Protection Policy Act ..................................................................................................... 141
4.2.11 Section 7 of the Endangered Species Act ....................................................................................... 142
4.2.12 Section 106 of the National Historic Preservation Act .................................................................. 142
4.2.13 Section 7(a) of the National Wild and Scenic Rivers Act ................................................................ 142
5. PUBLIC AND AGENCY INVOLVEMENT (AND PERMITS/APPROVALS) ....................................... 144
5.1 INFORMATIONAL PROCESS ............................................................................................................. 144
5.1.1 Public Engagement .......................................................................................................................... 144
5.1.2 Project Management Team ............................................................................................................. 147
Hwy 243 Osceola Bridge Project | Environmental Assessment/Environmental Assessment Worksheet
viii
5.1.3 Agency Coordination ....................................................................................................................... 147
5.2 SUMMARY OF EARLY COORDINATION COMMENTS ............................................................................ 149
5.2.1 Minnesota ........................................................................................................................................ 149
5.2.2 Wisconsin ......................................................................................................................................... 150
5.3 PUBLIC COMMENT PERIOD AND PUBLIC HEARING ............................................................................. 150
5.4 REPORT DISTRIBUTION .................................................................................................................. 151
5.5 PROCESS BEYOND THE HEARING ..................................................................................................... 151
Hwy 243 Osceola Bridge Project | Environmental Assessment/Environmental Assessment Worksheet
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List of Tables
Table 2-1. History of the Hwy 243 Bridge .................................................................................................................. 3
Table 2-2. Section 4(f) Properties within or near the Project Area ......................................................................... 11
Table 3-1. Overall Assessment of Alternatives in the Bridge Type Study ............................................................... 22
Table 4-1. Project Magnitude .................................................................................................................................. 30
Table 4-2. Climate Considerations and Adaptations ............................................................................................... 35
Table 4-3. Cover Types ............................................................................................................................................ 38
Table 4-4. Green Infrastructure ............................................................................................................................... 39
Table 4-5. Tree Removal .......................................................................................................................................... 39
Table 4-6. Permits and Approvals ............................................................................................................................ 42
Table 4-7. Soil Types within the Project Area .......................................................................................................... 50
Table 4-8. Wells within the Project Area ................................................................................................................. 58
Table 4-9. Estimated Impervious Surface Changes with the Project ...................................................................... 61
Table 4-10. Causeway Alternatives Analysis ........................................................................................................... 63
Table 4-11. Summary of Visual Impacts ................................................................................................................ 101
Table 4-12. MnDOT Greenhouse Gas Analysis Summary ...................................................................................... 113
Table 4-13. Typical Construction Equipment Noise Levels at 50 Feet .................................................................. 115
Table 4-14. Daily Traffic Volumes (Existing and Forecasted) ................................................................................ 119
Table 4-15. Hwy 243 Peak Hour Traffic Volumes .................................................................................................. 120
Table 4-16. Project Related Environmental Effects and Geographic Extent ......................................................... 121
Table 4-17. Reasonably Foreseeable Projects Near the Project Area and Detour Route ..................................... 125
Table 5-1. Public Engagement Activities ............................................................................................................... 146
Table 5-2. Cooperating and Participating Agencies .............................................................................................. 148
Table 5-3. Hwy 243 Osceola Bridge Project Concurrence Points .......................................................................... 148
List of Figures
Figure 0-1. State Location Map ................................................................................................................................. iv
Figure 0-2. Project Location Map ............................................................................................................................... v
Figure 2-1. Hwy 243 Bridge Over the St. Croix River ................................................................................................. 2
Figure 2-2. Underside of Hwy 243 Bridge Deck and Steel Truss ............................................................................... 4
Figure 2-3. Pedestrian and Bicycle Origins/Destinations, NPS Osceola Landing and Village of Osceola .................. 7
Figure 2-4. Hwy 243 Detour Routes to US Hwy 8 and Hwy 36 .................................................................................. 9
Figure 2-5. St. Croix National Scenic Riverway ........................................................................................................ 14
Figure 3-1. Hwy 243 Osceola Bridge Project Alternatives Evaluation Process ........................................................ 16
Figure 4-1. United States Geological Survey Topographical Map ........................................................................... 26
Figure 4-2. Existing Cover Types .............................................................................................................................. 41
Figure 4-3. Soil Types ............................................................................................................................................... 52
Figure 4-4. Water Resources ................................................................................................................................... 54
Figure 4-5. FEMA Floodplain FIRMette ................................................................................................................... 57
Figure 4-6. Wells within or near the Project Area ................................................................................................... 59
Figure 4-7. Area of Visual Effect and Visual Landscape Units ............................................................................... 100
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Figure 4-8. FHWA Projected National MSAT Emission Trends 2020-260 For Vehicles Operating On Roadways
Using EPA’s MOVES3 Model .................................................................................................................................. 107
Figure 4-9. Section 4(f) Resources within the Project Area ................................................................................... 135
List of Appendices
APPENDIX A (Figures)
APPENDIX B (Purpose & Need)
APPENDIX C (Alternatives)
APPENDIX D (Bridge Type Study)
APPENDIX E (Constructability Report)
APPENDIX F (Environmental Management Plan)
APPENDIX G (Wetland Assessment & Two-Part Finding)
APPENDIX H (Floodplain Assessment)
APPENDIX I (Contaminated Properties)
APPENDIX J (Agency Correspondence)
APPENDIX K (Biological Assessment)
APPENDIX L (Visual Impact Assessment)
APPENDIX M (Environmental Justice Analysis)
APPENDIX N (Section 4(f) Involvement – De Minimis Determination and Temporary Occupancies)
APPENDIX O (Benefit-Cost Analysis Memo)
APPENDIX P (NPS Section 7(a) Correspondence)
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List of Acronyms
Abbreviation Definition Abbreviation Definition
AADT Average Annual Daily Traffic LRFD Load and Resistance Factor Design
ABM Activity Based Model LTS Level of Traffic Stress
ACS American Community Survey MDH Minnesota Department of Health
ADA Americans with Disabilities Act MEPA Minnesota Environmental Policy Act
ADT Average Daily Traffic MEQB Minnesota Environmental Quality
Boards
AG Agricultural MIAC Minnesota Indian Affairs Council
AMMs Avoidance and Minimization Measures MMLOS Multimodal Level of Service
APE Area of Potential Effect MnDNR Minnesota Department of Natural
Resources
AVE Area of Visual Effect MnDOT Minnesota Department of
Transportation
B-1 General Commercial MOVES Motor Vehicle Emissions Simulator
BCA Benefit-Cost Analysis MPCA Minnesota Pollution Control Agency
BFE Base Flood Elevation MSAT Mobile Source Air Toxic
bgs below ground surface NBI National Bridge Inventory
BMP Best Management Practice NEPA National Environmental Policy Act
BORIS Bridge Office Replacement and
Improvement System NHIS Natural Heritage Information System
BPI Bridge Planning Index NPDES National Pollution Discharge
Elimination System
CAA Clean Air Act NPS National Park Service
CBD Commercial Business District NRCS Natural Resources Conservation
Service
CD Conservancy NRHP National Register of Historic Places
CFR Code of Federal Regulations NWSRA National Wild and Scenic Rivers Act
cfs cubic feet per second ODOT Oregon Department of
Transportation
CO Carbon Monoxide ORVs Outstandingly Remarkable Values
CRT Cultural Resources Team OSA Office of the State Archaeologist
CRU Cultural Resources Unit OWJ Officials with Jurisdiction
CSS Context Sensitive Solutions PCBs Polychlorinated biphenyls
EA Environmental Assessment PIP Public Involvement Plan
EAW Environmental Assessment Worksheet PMT Project Management Team
EIS Environmental Impact Statement PR Park and Recreation
EJ Environmental Justice RAP Response Action Plan
EMP Environmental Management Plan RCP Representative Concentration
Pathway
EPA Environmental Protection Agency RGU Responsible Governmental Unit
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Abbreviation Definition Abbreviation Definition
ERDB Ecosystems Research and
Development Bureau R-U Urban Single-Family
ERR Endangered Resources Review SEE Social, Economic, and Environmental
ESA Environmental Site Assessment SHPO State Historic Preservation Office
FAA Federal Aviation Administration SP State Project
FEMA Federal Emergency Management
Agency SSTS Subsurface Sewage Treatment
Systems
FHWA Federal Hwy Administration SWPPP Stormwater Pollution Prevention
Plan
FIRM Flood Insurance Rate Maps TPDP Transportation Project Development
Process
FIS Flood Insurance Studies TSS Total Suspended Solids
FONSI Finding of No Significant Impact USACE U.S. Army Corps of Engineers
FPPA Farmland Protection Policy Act USCG U.S. Coast Guard
GHG Greenhouse Gas USFWS U.S. Fish and Wildlife Service
HCM Hwy Capacity Manual USGS U.S. Geological Survey
HHS Department of Health and Human
Services VIA Visual Impact Assessment
Hwy Trunk Highway VMT Vehicle Miles Traveled
I-1 Light Industrial vpd vehicles per day
IPaC Information for Planning and
Consultation VQAC Visual Quality Advisory Committee
LA License Agreement VQM Visual Quality Manual
LAC Local Advisory Committee WCA Wetland Conservation Act
LWCF Land and Water Conservation Fund WisDNR Wisconsin Department of Natural
Resources
LO Lower St. Croix Overlay WisDOT Wisconsin Department of
Transportation
LOS Level of Service WPDES Wisconsin Pollution Discharge
Elimination System
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EXECUTIVE SUMMARY
Project Background
The Minnesota Department of Transportation (MnDOT), in cooperation with the Wisconsin Department of
Transportation (WisDOT), intends to address the condition of the Osceola Bridge (MnDOT Bridge No. 6347 and
WisDOT Bridge No. B-48-224), which carries Hwy 243 over the St. Croix National Scenic Riverway, a unit of the
National Park System and component of the National Wild and Scenic River System, between Franconia
township in Minnesota to the Village of Osceola in Wisconsin. The Hwy 243 Osceola Bridge Project includes
replacing the existing bridge with a new bridge, reconstructing 0.5 miles of Hwy 243, and constructing a sidepath
on the north side of the highway, herein referred to as a shared-use path (pedestrian, bicycle, and Americans
with Disabilities Act (ADA) improvements).1 MnDOT will act as the lead agency for the development, design, and
construction of the Hwy 243 Osceola Bridge Project. WisDOT will operate and maintain the Hwy 243 Bridge
following construction. The Federal Hwy Administration (FHWA) is the lead federal agency responsible for
approval of the National Environmental Policy Act (NEPA) process and documentation for this project.
MnDOT and WisDOT are working cooperatively on the planning, design, and decision-making for this project as
they currently do for the inspection and maintenance of the existing structure. All studies and reports
completed for the bridge are coordinated between both agencies. Both DOTs include the Hwy 243 Bridge in
their respective plans for major bridge improvements starting in 2026. MnDOT and WisDOT operate under a
50/50 cost-share agreement for all WI/MN border bridges.
Document Purpose
This Environmental Assessment (EA) provides information which includes:
• Need for the proposed project
• Alternatives considered
• Environmental impacts and associated mitigation
• Agency coordination and public involvement
This EA was prepared as part of the NEPA process and state environmental review, Minnesota Environmental
Policy Act (MEPA), process to fulfill requirements of 42 USC § 4332, Minnesota Statutes Chapter 116D, and
Wisconsin Environmental Policy Act (WEPA) Wisconsin Statutes 1.11.
Project Purpose and Need
MnDOT, in cooperation with WisDOT and FHWA, identified the following transportation problems or
deficiencies which justify the need for the Hwy 243 Osceola Bridge Project. The needs have been categorized as
1 Shared-use path is a term that is interchangeable with the structures term “sidepath,” which was used during the alternatives analysis
for this project. Sidepath was used in previous documentation because of its use in the MnDOT LRFD Bridge Design Manual. Sidepaths are
shared-use paths parallel to the roadway that are physically separated from motor vehicle traffic.
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primary and secondary needs, as defined below.
• Primary needs include the most significant transportation problems in the project area. Bridge condition
was identified as the one primary need for the project. The existing bridge is in poor condition and has
deteriorating elements that need attention.
• Secondary needs are other transportation problems that may be able to be addressed at the same time
as primary needs. Walkability/bikeability was a secondary need identified for the project because the
Hwy 243 Bridge is located between two pedestrian and bicycle generators, multimodal level of service is
poor for bicyclists, and level of traffic stress is high for both pedestrians and bicyclists.
• Additional considerations are other desirable project elements or effects that are not central to the
purpose and need but are nonetheless important considerations to identifying a Preferred Alternative.
The following subjects were identified as additional considerations which helped guide project
development and the alternatives evaluation process for the project:
o Maintenance of traffic during construction
o Osceola Landing (NPS owned)
o Stormwater management
o Regulatory requirements
o Ecological connectivity
Alternatives
The project has completed the alternatives development, screening, and evaluation process. The objective of
this process was to identify Build Alternatives to progress for further evaluation, and to reach a Preferred
Alternative to move forward into the EA. The process involved numerous steps, including a high-level concept
development and screening, followed by an increasingly more detailed evaluation of alternatives. Public and
agency input was solicited at several points during this process. The process began with purpose and need
development which underwent review and approval, then proceeded with defining evaluation criteria and
performance measures. These are based on project needs and additional considerations, as well as social,
economic, and environmental (SEE) criteria. The SEE categories included as evaluation criteria were those that
had the potential to be differentiators for screening concepts/alternatives. The selected SEE categories provided
a basis for understanding potential impacts and an opportunity for modification of alternatives. Performance
measures were developed for each evaluation criteria. While the evaluation criteria categories remained
constant, the performance measures were refined as the project developed and existing environmental data
was gathered.
The alternatives evaluation included a multi-step process. A range of potential concepts was developed in the
first step, including the No Build Alternative to serve as the basis of comparison. The project team initially
studied the following seven concepts:
• No Build Alternative
• Build Concept A – Rehabilitation
• Build Concept B – Existing Alignment
• Build Concept C – North Alignment
• Build Concept D – South Alignment
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• Build Concept E – 2nd Avenue Alignment
• Build Concept F – New Alignment
• Build Concept G – Tunnel Alignment
Several of the concepts were rejected from further study due to poor performance across one or more
evaluation criteria. Following this initial concept screening and evaluation process, MnDOT and WisDOT
advanced three Build Alternatives for further evaluation, as well as a No Build Alternative to serve as a basis for
comparison. The Build Alternatives identify both the bridge’s horizontal and vertical alignment, in addition to
the location of a shared-use path. The Level 1 evaluation screened concepts, which were then refined into
alternatives for subsequent screenings after Level 1. The following alternatives were studied in Step 2 and Step 3
of the alternatives evaluation process:
• No Build Alternative
• Build Alternative B – Existing Alignment
• Build Alternative C – North Alignment
• Build Alternative D – South Alignment
Step 2 included an initial evaluation of the three build alternatives. The outcome of Step 2 indicated that there
was not adequate information to justify eliminating an alternative from further study. Therefore, all three build
alternatives were carried forward and developed to a more refined level of detail in Step 3. The outcome of Step
3 was the identification of a preferred alternative for the project.
Preferred Alternative
FHWA, MnDOT, and WisDOT are collectively recommending one alternative in the EA to advance for further
design, engineering, and construction. The key differences in the seven Build Concepts studied during the NEPA
process are the bridge alignment over the St. Croix River, potential impacts to the outstandingly remarkable
values (ORVs) of the St. Croix National Scenic Riverway (“the Riverway”) and other SEE impacts, constructability,
and maintenance of traffic. A brief summary of alternatives analysis is provided below.
• The rehabilitation alternative (Build Concept A) is not recommended for further consideration because
an engineering analysis of the existing piers determined that there is not adequate capacity in the
existing piers to support a new bridge deck and superstructure.
• Build Concept F would create a new highway corridor in the St. Croix National Scenic Riverway. This new
highway corridor and crossing of the St. Croix River has a high likelihood of adverse effects to the ORVs
unique to the Riverway.
• Build Concept E was dismissed from further consideration because of changes in traffic patterns in the
Village of Osceola and anticipated impacts to the Osceola Commercial Historic District.
• Build Concept G (the tunnel alignment) was dismissed for several reasons; the tunnel concept
represented the highest magnitude of asset to manage and would require more costly repairs in its
lifespan compared to a bridge, pedestrian or bicycle accommodations would not be feasible within the
tunnel, and tunnels have greater operational requirements compared to bridges.
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• Build Alternatives B, C, and D were retained for consideration in a third step of the alternatives
screening and evaluation. Design refinements occurred at this stage, such as the alignments, typical
sections, shared-use path design options, stormwater basin location, and rock slope investigation.
• Build Alternative B results in the longest crossing closure time, but also results in the shortest overall
duration of construction; requires one river access for bridge construction, minimizing in-water impacts
compared to the off-alignment alternatives.
• Build Alternative C and Build Alternative D require two river accesses for bridge construction; minimizes
potential impacts to the surrounding natural environment relative to Build Alternative C and Build
Alternative D; river navigation is maintained during construction with all three build alternatives;
however, Build Alternative C and Build Alternative D require one additional construction season for in-
water work to remove the existing Hwy 243 Bridge; lastly, Build Alternative B avoids right of way
acquisition.
The existing alignment alternative is likely to result in the least amount of overall adverse impacts to the
surrounding environment and community. Therefore, MnDOT, WisDOT, and FHWA are recommending that
Build Alternative B (existing alignment) be advanced into detail design and engineering. Additional details
regarding the alternatives analysis can be found in Chapter 3 - ALTERNATIVES and APPENDIX C (Alternatives).
Environmental Commitments
All avoidance, minimization, and mitigation measures, also known as environmental commitments, are
documented in this project’s Environmental Management Plan, which can be found in APPENDIX F
(Environmental Management Plan).
Opportunities for Public Comment
Comments from the public and agencies affected by this project are requested during the public comment
period described on the transmittal letter distributing this EA/EAW. Copies of this document have been sent to
agencies, local government units, libraries, and others per Minnesota Rules, part 4410.1500 and Chapter 6 of
the WisDOT Facilities Development Manual. The notice of availability will be published in the EQB Monitor, and
noticed through a press release to the local Franconia Township and Village of Osceola area paper(s), and on the
project website: https://www.dot.state.mn.us/metro/projects/hwy243osceola/.
A public hearing will be held on December 10, 2024, which is after the EA/EAW has been distributed to the
public and to the required and interested federal, state, and local agencies and Native American Tribes for their
review.
Comments on the EA will be accepted from November 26, 2024 through December 26, 2024 and may be
submitted through email, mail, or in person at the public hearing.
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1. REPORT PURPOSE
This EA provides background information including:
• need for the proposed project
• alternatives considered
• environmental impacts and mitigation
• agency coordination and public involvement
This EA was prepared as a part of the NEPA process and state environmental review process to fulfill requirements
of 42 USC 4332, Minnesota Statute 116D, and Wisconsin Statute 1.11.
At the federal level, the EA is used to provide sufficient environmental documentation to determine the need for
an Environmental Impact Statement (EIS) or that a Finding of No Significant Impact (FONSI) is appropriate. FHWA
is the lead federal agency responsible for approval of the NEPA process and documentation for this project.
MnDOT will act as the lead agency for the development, design, and construction of the Hwy 243 Bridge, per the
border bridge cooperative agreement with WisDOT. The environmental processes and requirements will be
followed for the respective state in which the project falls.
At the Minnesota state level, this document also serves as an Environmental Assessment Worksheet (EAW). The
EAW is used to provide sufficient environmental documentation to determine the need for a state EIS or that a
Negative Declaration is appropriate. Minnesota Rules, part 4410.1300 allows the EA to take the place of the
EAW form, provided that the EA addresses each of the environmental effects identified in the EAW form. This EA
includes each of the environmental effects identified in the EAW form. MnDOT is the proposer and Responsible
Governmental Unit (RGU) for this project. Preparation of an EAW for this project is considered discretionary
under Minnesota Rules, part 4410.
At the Wisconsin state level, this document also fulfills the requirements of the Wisconsin Environmental Policy
Act (WEPA) under Wisconsin Statutes, Section 1.11.
This document is made available for public review and comment in accordance with the requirements of 23
Code of Federal Regulations (CFR) 771.119 (d) and Minnesota Rules 4410.1500 through 4410.1600. A public
hearing will be held during the public review and comment period.
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2. PURPOSE AND NEED FOR PROJECT
MnDOT, in coordination with WisDOT and FHWA, identified the following transportation problems or
deficiencies which justify the need for the Hwy 243 Osceola Bridge Project. The needs have been classified as
primary or secondary as defined below. The Hwy 243 Bridge over the St Croix River (MnDOT Bridge No. 6347
and WisDOT Bridge No. B-48-224) has existing concerns.
2.1 Primary Need: Bridge Condition
The Hwy 243 Bridge over the St. Croix River (MnDOT Bridge No. 6347 and WisDOT Bridge No. B-48-224) was
built in 1953 and is a five-span, fracture critical, deck truss structure (see Figure 2-1). The Hwy 243 Bridge
extends from the Wisconsin bluff to the Minnesota bluff above the St. Croix River on a three percent grade. The
Hwy 243 Bridge deck is 34.2 feet wide. There are two lanes on the bridge: one 12-foot-wide eastbound Hwy 243
lane and one 12-foot-wide westbound Hwy 243 lane. The bridge includes 3.6-foot-wide outside shoulders in
each direction. The Hwy 243 Bridge is load posted at 40 tons and currently carries approximately 5,600 vehicles
per day (vpd). The posted speed limit is 45 mph on the Minnesota side of the St. Croix River and transitions to 35
mph on the Wisconsin side of the river. Table 2-1 summarizes the history of construction and maintenance of
the Hwy 243 Osceola Bridge.
Figure 2-1. Hwy 243 Bridge Over the St. Croix River
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Table 2-1. History of the Hwy 243 Bridge
Year Construction/Repair Project Summary of Work
1953 Bridge construction Built a five-span, fracture critical,
deck truss structure
1980 Reconstruction Reconstructed bridge elements
1985 Maintenance Trusses were painted
2010 Rehabilitation Reconstructed; isolated areas of
deck removed and reconstructed;
expansion joint reconstructed;
installed a chip seal overlay; new
railings to accommodate bicyclists;
replaced bridge deck drains; and
repaired concrete surface of the
abutments and piers
2017 Deck repairs Removed and reconstructed deck
areas, sealed deck cracks, and
replaced the deck chip seal with an
ultrathin bonded wearing course
MnDOT Metro District, the MnDOT Bridge Office, and WisDOT have identified the Hwy 243 Bridge over the St.
Croix River as having deteriorated elements that need attention. Figure 2-2. Underside of Hwy 243 Bridge Deck
and Steel Truss depicts some of the deficiencies of the Hwy 243 Bridge. An inspection of the Hwy 243 Bridge
completed in April 2024 and noted the following conditions:
• Deck: The Hwy 243 Bridge was closed in 2017 due to the appearance of a large hole in the bridge deck.
In 2019, it was noted that the underside of the deck has extensive deterioration including leaching, rust
staining, delamination, and spalls with rusting rebar. There are scattered areas of delamination and
spalling along the underside of the copings.
• Truss Members: The truss bottom chord has scattered minor pitting in the top surfaces. The top
surfaces of the bottom chord members have pigeon debris, paint failure, and surface corrosion with
scattered areas of flaking rust. The truss was last painted in 1985. The top chord has surface rust and
flaking rust at the span ends at the abutments and piers. There are some isolated areas of corrosion
below deck leaching cracks. In 2019, inspectors found some bowing/bulging in a vertical member on the
south truss and in the north truss in Span 4.
• Truss Gusset Plates: The truss gusset plates have scattered areas of bubbling paint and surface
corrosion. The bottom chord connections have a buildup of debris and moisture, causing corrosion. The
top chord connections at the piers have staining and corrosion. The bottom chord gusset plates and
connection plates have pack rust along the edges which are causing the plates to bow. Some bottom
chord gusset plates have flaking rust with pitting along the top edge of the bottom chord. There are
some gusset plates with pitting up to ¼-inch deep.
• Steel Floor Beams: The lower floor beams have extensive pitting on the flanges and web throughout and
have scattered areas of paint failure, surface corrosion, and flaking rust.
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• Steel Lateral Bracing: The lower lateral bracing has scattered areas of surface corrosion, flaking rust
(minor pitting/section loss), and pack rust. The vertical sway bracing has scattered areas of surface
corrosion and flaking rust. The lower transverse struts have scattered areas of surface corrosion and
flaking rust.
• Concrete Piers: The pier columns have some areas of scale, with isolated rust stains and minor spalls.
The concrete web walls have minor cracking, areas of repair patches, and isolated rust stains. Concrete
columns on Pier 2 exhibit spalling with exposed rebar.
• Bearings: Most of the expansion bearings have “settled” into their masonry/bearing plates due to
corrosion. Two expansion bearings have not moved since 2013 (the rocker bearings should move with
temperature induced expansion/contraction of the bridge).
Figure 2-2. Underside of Hwy 243 Bridge Deck and Steel Truss
The National Bridge Inventory (NBI) ratings describe the general overall condition of the structure on a scale of 0
(failed condition, bridge is closed) to 9 (excellent, or “new” condition). The NBI rating reported the Hwy 243
Bridge at a four (4). This is a poor condition rating. The NBI rating reported the Hwy 243 Bridge superstructure at
a five (5) and the substructure at a six (6), which are fair and satisfactory condition ratings, respectively. On
average, a bridge deck with a NBI rating of four will reach a failed condition within 10 years without on-going
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maintenance and repairs. A bridge superstructure with a NBI rating of five will reach a poor condition within 10
to 30 years without on-going maintenance and repairs.
MnDOT’s Bridge Planning Index (BPI) as provided by the Bridge Office Replacement and Improvement System
(BORIS) tool ranks the Hwy 243 Bridge as the number six (6) priority out of all the bridges in the MnDOT Metro
District. There are 1,203 bridges in the BORIS tool for MnDOT Metro District. The BORIS tool helps preparation
for bridge investment projects by forecasting future work types, costs, and schedules for a 20-year planning
horizon.
2.2 Secondary Need: Walkability/Bikeability
The Hwy 243 Bridge is the only facility in the area that allows pedestrians, cyclists, and other non-motorized
traffic to cross the St. Croix River. The Hwy 243 Bridge has 3.6-foot-wide shoulders on both sides of the
structure; this width does not meet MnDOT standards for pedestrian use. Section 2.1.2 in the MnDOT Load and
Resistance Factor Design (LRFD) Bridge Design Manual specifies a minimum shared-use path width of 10 feet for
new vehicular bridges. The existing average daily traffic volume on the Hwy 243 Bridge is 5,600 vpd with
increases in traffic volumes during the summer months. The posted speed limit on Hwy 243 transitions from 45
mph in Minnesota to 35 mph in Wisconsin. Figure 2-3. Pedestrian and Bicycle Origins/Destinations, NPS Osceola
Landing and Village of Osceola illustrates pedestrian and bicycle origins and destinations in and around the
Village of Osceola, the Osceola Landing, and the Hwy 243 Bridge.
On average, 12 cyclists using the Strava application cross the St. Croix River on the Hwy 243 Bridge daily with an
increase in the number of users during the summer months. The Hwy 243 Bridge connects two pedestrian and
bicycle generators, the Village of Osceola, and Osceola Landing. The Village of Osceola (on the east side of the
St. Croix River) is a destination for tourists visiting the St. Croix National Scenic Riverway and offers many
recreational resources, businesses, and restaurants. Osceola Landing (on the west side of the St. Croix River)
provides motorized and non-motorized access to the St. Croix River and includes a recreational day-use area for
picnicking, walking, and fishing. The Osceola Landing is the busiest landing maintained and operated by the
National Park Service (NPS) on the St. Croix River.
The mobility performance of existing pedestrian and bicycle facilities in the Hwy 243 corridor, including the Hwy
243 Osceola Bridge, was evaluated utilizing the pedestrian and bicycle multimodal level of service (MMLOS) for
segments as developed by Oregon Department of Transportation (ODOT). This methodology is used to create
the Hwy Capacity Manual (HCM) Pedestrian and Bicycle Level of Service (LOS) on segments. Pedestrian LOS on
segments is estimated from four variables: actual sidewalk width, directional hourly traffic volume, number of
through traffic lanes per direction, and posted speed limit. Bicycle LOS on segments is estimated from the
following four variables: number of through traffic lanes per direction, presence of bike lane or paved shoulder,
posted speed limit, and unsignalized conflicts. LOS scores are based on user perceptions and graded from best
(LOS A) to worst (LOS F) and were grouped into LOS ranges. The results represent the probability that a user will
pick a given LOS or range of LOS.
The MMLOS for Hwy 243 was supplemented with a pedestrian and bicycle level of traffic stress (LTS) analysis as
developed by ODOT. The pedestrian LTS methodology classifies roadways based on the level of pressure or
strain experienced by pedestrians. Pedestrian LTS for segments is estimated from a number of variables,
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including: sidewalk condition and width; buffer type and width; number of lanes and posted speeds; lighting
presence; and general land use. The pedestrian LTS methodology is intended for use in urban areas; however, it
can be used in rural areas where facilities exist. Pedestrian LTS uses four levels of traffic stress classifications,
with LTS 1 representing the lowest stress condition and LTS 4 representing the highest stress condition. The
bicycle LTS methodology divides roadway segments into categories based on the effects of traffic-based stress
on bicycle riders. The measure of traffic stress quantifies perceived safety and comfort based on proximity to
vehicles, considering both space and vehicle speed. The methodology for application to rural environments
considers paved shoulder width, traffic volumes, and speeds (e.g., less than or greater than 45 mph). Bicycle LTS
uses four levels of traffic stress classifications, with LTS 1 representing the lowest level of stress and LTS 4
representing the highest level of stress.
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Figure 2-3. Pedestrian and Bicycle Origins/Destinations, NPS Osceola Landing and Village of Osceola
Note: the wayside rest area is owned by MnDOT.
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The Hwy 243 segment was defined as between the Osceola Landing and Hwy 243/WIS-35 intersection. Hwy 243
performs at LOS C-E for pedestrians and LOS F for bicycles according to the MMLOS analysis. Regarding the LTS
analysis, the Hwy 243 segment performs at pedestrian LTS 4 and bicycle LTS 4. The high pedestrian LTS is
because there is no separate sidewalk and the narrow shoulders create an uncomfortable condition for
pedestrians. The high bicycle LTS is because the narrow shoulders and proximity to vehicular traffic at posted
speeds of 45 mph on the Hwy 243 Osceola Bridge is suitable for highly confident bicyclists; however, it is not a
comfortable condition for most bicyclists (e.g., bicyclists with low tolerance for traffic stress, recreational
bicyclists).
2.3 Additional Considerations
Additional considerations are elements that are not central to the purpose and need of the project but are
important criteria for evaluating build alternatives. The additional considerations identified for this project
include:
• Maintenance of traffic during construction
• Osceola Landing
• Stormwater management
• Regulatory requirements
• Ecological connectivity
2.3.1 Maintenance of Traffic During Construction
Maintenance of traffic during construction includes vehicle mobility, as well as St. Croix River navigation and
access. Maintaining the reasonable continuity of vehicular traffic during construction will be critical given the
Hwy 243 Bridge function in the region’s transportation system. The closest St. Croix River crossing is at US Hwy 8
between Taylors Falls, Minnesota and St. Croix Falls, Wisconsin. The detour length for a round-trip between Hwy
243 and US Hwy 8 is approximately 18 miles, and the drive time is approximately 30 minutes. Figure 2-4. Hwy
243 Detour to US Hwy 8 in St. Croix Falls and Taylors Falls illustrates the detour route from Osceola to St. Croix
Falls/Taylors Falls, and back south to the Hwy 243 and MN-95 intersection. Emergency service providers in the
Village of Osceola will respond to incidents in Minnesota, including at the Osceola Landing, depending on the
incident, availability of emergency service responders, and response times. Emergency service providers from
Chisago County, the Village of Osceola, and Polk County will use the Osceola Landing to access the St. Croix River
to respond to incidents on the Riverway. Additional information regarding maintenance of traffic during
construction can be found in Section 4.1.20 Transportation.
2.3.2 Osceola Landing
The Osceola Landing access to Hwy 243 is approximately 600 feet west of the Hwy 243 Bridge. The Osceola
Landing is the busiest landing is owned and operated by the NPS on the St. Croix National Scenic River, with the
greatest use during the summer months. The Osceola Landing includes two side-by-side launches used by
motorized and non-motorized watercraft (boats, canoes, kayaks). Osceola Landing users include vehicles with
trailers and private outfitters with shuttle services. There is a right-turn lane on eastbound Hwy 243 to the
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Osceola Landing; however, there is no left turn lane on westbound Hwy 243 at the Osceola Landing access. This
project provides the opportunity to improve vehicular access from Hwy 243 to the Osceola Landing.
The NPS is planning improvements for the Osceola Landing. The purpose of these improvements is to increase
safety, improve operations for commercial use, and enhance the overall visitor experience. The Osceola Landing
improvements are anticipated to be implemented in two phases. The first phase was completed in 2023. The
second phase will be constructed following Hwy 243 Bridge construction. This project provides the opportunity
to coordinate Osceola Landing improvements with Hwy 243 Bridge construction.
Figure 2-4. Hwy 243 Detour Routes to US Hwy 8 and Hwy 36
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2.3.3 Stormwater Management
The existing Hwy 243 bridge deck includes catch basins connected to pipes that convey stormwater runoff
directly to the St. Croix River. Roadway contaminants (e.g., gasoline, oil, salt, etc.) or accidental spills of
materials also drain directly to the St. Croix River. The St. Croix River exhibits outstanding water quality and is
identified as an “outstanding resource water” by Minnesota and Wisconsin. The water quality of the St. Croix
River also is an important criterion for its inclusion in the National Park Service Wild and Scenic Rivers System.
The stretch of the St. Croix River from the Taylors Falls Dam to Lake St. Croix, including the Hwy 243 crossing, is
impaired for mercury, nutrients, and polychlorinated biphenyls (PCBs) in fish tissue.
Hwy 243 on the west side of the St. Croix River in Minnesota includes curb and gutter and catch basins along the
edge of the roadway. These features, along with storm sewer and culverts, convey stormwater runoff from Hwy
243 to receiving waters. An existing culvert is on the south side of Hwy 243 between the Osceola Landing access
and the Hwy 243 Bridge. This culvert conveys stormwater from Hwy 243, under the Osceola Landing driveway,
to the St. Croix River. The end of this culvert is outside of MnDOT trunk highway right of way.
This project provides the opportunity to improve stormwater management from the Hwy 243 Bridge prior to
discharge to the St. Croix River and to bring existing stormwater management features into compliance with NPS
and MnDOT right of way requirements.
2.3.4 Regulatory Requirements
The planning and development process for the Hwy 243 Osceola Bridge Project must consider several federal
and state regulatory requirements. These are summarized below.
2.3.5.1 Historic Resources
The Osceola Commercial Historic District is in downtown Osceola along North Cascade Street (WIS-35),
northeast of the Hwy 243 Bridge over the St. Croix River. The Osceola Commercial Historic District is listed on
the National Register of Historic Places (NRHP) and encompasses the central business district of the Village of
Osceola. The Osceola Commercial Historic District is along two blocks of North Cascade Street and includes 23
buildings (17 contributing and 6 non-contributing).
2.3.5.2 Section 4(f) Properties
Section 4(f) provides protections for publicly owned parks, trails, recreational areas, and wildlife and waterfowl
refuges, and historic properties determined eligible or listed on the NRHP. Table 2-2. Section 4(f) Properties
within or near the Project Area lists Section 4(f) properties in the study area and their Official with Jurisdiction
(OWJ).
Table 2-2. Section 4(f) Properties within or near the Project Area
Section 4(f) Resource Official With Jurisdiction
St. Croix National Scenic Riverway (includes Osceola Landing, part of
the National Park System and component of the Wild and Scenic Rivers
System)
NPS
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Section 4(f) Resource Official With Jurisdiction
St. Croix State Water Trail MnDNR
Cascade Falls and Wilke Glen Conservancy/Open Space (includes Falls
Bluff Trail Loop system)
Village of Osceola
Gristmill Park Village of Osceola
Millpond Park Village of Osceola
Osceola Picnic Bluff (includes Simenstad and Eagle Bluff Trails) Village of Osceola
Osceola Commercial Historic District Wisconsin State Historic
Preservation Office (SHPO)
2.3.5.3 Protected Species
The St. Croix River is home to more than 40 native freshwater mussels, including many state and federally-listed
threatened and endangered mussels. Federally listed mussel species anticipated to occur in the project area
include Higgins eye pearlymussel (Lampsilis higginsii), snuffbox (Epioblasma triquetra), spectaclecase
(Cumberlandia monodonta), and winged mapleleaf (Quadrula fragosa). Additionally, the proposed federally
endangered salamander mussel (Simpsonaias ambigua) and proposed Critical Habitat occur in this reach of the
St. Croix River. Freshwater mussels play an important role in maintaining water quality in the St. Croix River by
filtering water and aquatic nutrients.2 Surveys completed by the Minnesota Department of Natural Resources
(MnDNR) and Macalester College indicate that state and federally-listed mussels inhabit the St. Croix River in the
vicinity of the Hwy 243 Bridge. The St. Croix River also provides habitat for several Minnesota and Wisconsin
state-listed fish species.
The project is within the range of the northern long-eared bat (Myotis septentrionalis), a federally-endangered
species and the tri-colored bat (Perimyotis subflaus), a federally proposed-endangered species. Other non-listed
bats in the study area include the big brown bat (Eptesicus fuscus), little brown bat (Myotis lucifugus), and hoary
bat (Lasiurus cinereus). All three of these bat species are state-listed as threatened in Wisconsin. The little brown
bat (Myotis lucifugus) and hoary bat (Lasiurus cinereus) are included in the U.S. Fish & Wildlife Service (USFWS)
work plan for evaluation for potential protection under the Endangered Species Act. Bats and evidence of bats
are present on the Hwy 243 Bridge. Previous bridge inspections have noted bat guano on top of all piers and on
both abutments. Bats have been observed in the strip seal deck joints at all four bridge piers. A documented bat
hibernaculum is also present in the study area.
2.3.5.4 St. Croix River Navigation
The US Coast Guard (USCG) has jurisdiction over structures spanning the St. Croix River. The General Bridge Act
of 1946 requires the location and plans for bridges over navigable waters of the United States to be approved by
the Commandant of the USCG prior to the start of construction. A USCG Section 9 permit will be required for
this project. USCG has stated that any Hwy 243 crossing of the St. Croix River must meet or exceed the vertical
2 US Department of Interior. National Park Service. September 2017. Foundation Document. St. Croix National Scenic Riverway.
Minnesota and Wisconsin available at https://www.nps.gov/sacn/learn/management/foundation-document.htm#SACN.
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and horizontal clearances provided by the existing Hwy 243 Bridge. See USCG correspondence in APPENDIX J
(Agency Correspondence).
2.3.5.5 St. Croix National Scenic Riverway
The St. Croix National Scenic Riverway is a unit of the National Park System administered by the NPS and a
component of the Wild and Scenic Rivers System. In 1968, the U.S. Congress established the St. Croix National
Scenic Riverway, including the Namekagon River, as one of eight rivers protected under the National Wild and
Scenic Rivers Act (NWSRA). The Lower St. Croix National Scenic Riverway was added in 1972. The purpose
statement from the NPS Foundation Document, St. Croix National Scenic Riverway identifies the important
values of the St. Croix National Scenic Riverway:1
The values for which the Riverway has been designated as a wild and scenic river include its free-flowing
character, exceptional water quality, and the aquatic, riparian, recreational, cultural/historic, geologic, scenic,
and aesthetic values present in the rivers.
The St. Croix and Namekagon rivers total 255 miles from their headwaters in northwest Wisconsin downstream
to the confluence with the Mississippi River in Prescott, Wisconsin. The NPS management of the St. Croix
National Scenic Riverway extends 230 miles from the headwaters of the St. Croix and Namekagon rivers to near
the Boom Site north of Stillwater, Minnesota. The remaining 25 miles of the St. Croix River are part of the
national wild and scenic rivers system and are managed by the States of Minnesota and Wisconsin. Figure 2-5.
St. Croix National Scenic Riverway on the following page, from the NPS Foundation Document, St. Croix National
Scenic Riverway, illustrates the St. Croix National Scenic Riverway and the location of the Hwy 243 Bridge. The
NPS Foundations Document defines 11 river segments along the St. Croix National Scenic River. This project is in
Segment 8: St. Croix Falls to Osceola Landing and Segment 9: Osceola to Marine on St. Croix.
Section 7(a) of the NWSRA provides national wild and scenic rivers with permanent protection from federally-
licensed or assisted dams, diversions, channelization or other water resources projects that would have a direct
and adverse effect on its free-flowing condition, water quality, or ORVs. Bridge projects, including the Hwy 243
Osceola Bridge Project, are considered a water resources project under the NWSRA.
The NPS retains the responsibility for Section 7(a) determinations. Federal-aid funds and federal permits will be
required for the Hwy 243 Osceola Bridge Project. This project is subject to review by NPS and must be evaluated
in accordance with Section 7(a) of the National Wild and Scenic Rivers Act. The Section 7(a) evaluation for this
project will include an analysis of free-flowing conditions, water quality, and the six ORVs present at the Hwy
243 Bridge crossing location (aquatic, cultural, recreation, riparian, scenic/aesthetic, and geology).
2.3.5 Ecological Connectivity
The Hwy 243 corridor is adjacent to large areas along the St. Croix River identified by the Minnesota DNR as sites
of biodiversity significance. These areas are ranked in the “outstanding” category for their high-quality
vegetative composition. Outstanding sites of biodiversity significance contain occurrences of rare species, rare
native plant communities, and represent large, ecologically intact/functional landscapes.
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The Hwy 243 (existing) causeway bisects these sites of biodiversity significance and the St. Croix River floodplain.
Floodplain forests and backwater, shallow marshes are located along the Minnesota shoreline of the St. Croix
River to the north and south of the Hwy 243 causeway. The Hwy 243 causeway blocks old channels and restricts
flood flow between the backwater, shallow marshes. The Hwy 243 causeway may also be impeding north-south
wildlife movement through the St. Croix River valley. Wildlife must cross over Hwy 243 or find their way under
the Hwy 243 Bridge along the Minnesota shoreline through the Osceola Landing site.
This project provides the opportunity to improve ecological connectivity for rare species (e.g., turtles) and other
wildlife species and to re-establish flood flow between backwater shallow marshes along the Hwy 243 corridor.
The remainder of this page is intentionally left blank.
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Figure 2-5. St. Croix National Scenic Riverway
Source: US Department of Interior. National Park Service. September 2017. Foundation Document. St. Croix National Scenic Riverway.
Minnesota and Wisconsin available at https://www.nps.gov/sacn/learn/management/foundation-document.htm#SACN.
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3. ALTERNATIVES
An alternatives evaluation process and evaluation criteria have been identified for the Hwy 243 Osceola Bridge
Project. This process and evaluation criteria were documented in a report that was provided for Cooperating
and Participating Agency review. This report was also published on the project webpage for a 15-day public
review period. APPENDIX C includes the Hwy 243 Osceola Bridge Project Alternatives Evaluation Criteria Report
(June 2021), including detailed evaluation matrices.
The alternatives evaluation for the Hwy 243 Osceola Bridge Project will use a three-step process. This process
begins with identifying a reasonable range of build concepts, including a no build alternative. Each step includes
a progressively greater level of design detail and quantitative and qualitative environmental analysis. The
outcome of the third step is the identification of a Preferred Alternative for the Hwy 243 Osceola Bridge Project.
The alternatives evaluation process is summarized below.
1. Step 1: Do the alternatives address the primary need for the Hwy 243 Osceola Bridge Project (i.e., the
problems that led to the initiation of the project)? “Fatal flaw” assessment of alternatives. Fatal flaws
include an un-mitigable environmental impact (e.g., the complete loss of a high-quality, significant
environmental resource that cannot be replaced), is not fiscally attainable, or is not constructable.
2. Step 2: Do the alternatives address the secondary needs for the Hwy 243 Osceola Bridge Project?
Qualitative and quantitative assessment of other considerations and initial assessment of SEE impacts.
3. Step 3: Detailed quantitative and qualitative assessment of SEE impacts.
Figure 3-1. Hwy 243 Osceola Bridge Project Alternatives Evaluation Process on the following page illustrates the
three-step alternatives evaluation process for the Hwy 243 Osceola Bridge Project. The following sections
describe each step of the alternatives evaluation in more detail. The Alternatives Evaluation Criteria Report in
APPENDIX C identifies the evaluation criteria, performance measures, and methodologies used in each step of
the evaluation process.
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Figure 3-1. Hwy 243 Osceola Bridge Project Alternatives Evaluation Process
3.1 Alternatives Considered but Rejected
3.1.1 Build Concept A: Rehabilitate existing bridge. Replace deck and superstructure. Re-use
existing piers.
Build Concept A is the rehabilitation concept. Build Concept A includes removal of the existing Hwy 243 Bridge
deck and superstructure and replacement with a new deck and superstructure. The existing bridge piers would
remain in place and be re-used with the rehabilitation concept.
Step 1 Evaluation: Build Concept A was dismissed from further consideration because it only partially addresses
the primary bridge condition needs for this project. This build concept extends the service life of the bridge deck
and superstructure, but does not improve the condition of the substructure. Additionally, this concept does not
replace the bridge piers, meaning there would not be adequate capacity to support a new bridge deck and
superstructure.
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3.1.2 Build Concept F: New Hwy 243 Bridge on new alignment between MN-95 and WIS-35
Build Concept F includes constructing a new bridge crossing along an entirely new Hwy 243 alignment between
MN-95 and WIS-35 outside of the Village of Osceola. The existing Hwy 243 Bridge and existing Hwy 243
approach roadways in Minnesota and Wisconsin would be removed.
Step 1 Evaluation: Build Concept F was dismissed from further consideration because it would create a new
highway corridor in the St. Croix National Scenic Riverway and has a high likelihood of adverse effects to the
Riverway’s ORVs and would not be consistent with the Riverway’s anti-degradation requirement. This concept
would also likely harm other protected resources on both sides of the St. Croix River.
3.1.3 Build Concept E: New Hwy 243 Bridge along 2nd Avenue alignment in WI
Build Concept E includes constructing a new bridge crossing north of the existing Hwy 243 Bridge. The Concept E
alignment follows the original Hwy 243 crossing alignment that was in place prior to construction of the existing
Hwy 243 Bridge in the 1950’s. The Concept E alignment follows the 2nd Avenue corridor along the Wisconsin
bluff to WIS-35 in the Village of Osceola. The existing Hwy 243 Bridge would be removed.
Step 1 Evaluation: Build Concept E addresses the bridge condition need for this project as it includes completely
removing the existing Hwy 243 Bridge and constructing a new structure. This construction would include the
construction of a new bridge deck, superstructure, and substructure. This build concept has a 75-year plus
service life. Build Concept is in proximity to the existing bridge and would be approximately 250 feet north of the
existing Hwy 243 Bridge at the Wisconsin shoreline.
• Step 1a: However, this build concept was dismissed from further consideration because of changes in
traffic patterns in the Village of Osceola and anticipated impacts to the Osceola Commercial Historic
District.
3.1.4 Build Concept G: Tunnel crossing under St. Croix River along existing Hwy 243
alignment
Build Concept G includes constructing a tunnel under the St. Croix River along the existing Hwy 243 alignment
from Minnesota to Wisconsin. The existing Hwy 243 Bridge and Hwy 243 approach roadway in Wisconsin would
be removed. The Hwy 243 approach roadway in Minnesota would be maintained to provide access to the NPS
Osceola Landing. Build Concept G includes two potential alignments in Wisconsin: one along WIS-35 and one
along County Hwy M (County M). The total length of the tunnel concept (tunnel, tunnel portals, and approach
roadways) is approximately 1.9 miles.
Step 1 Evaluation: Build Concept G addresses the bridge condition need for this project as it includes completely
removing the existing Hwy 243 Bridge and constructing a new structure. This construction would include the
construction of a new tunnel structure under the St. Croix River. Build Concept G would follow the existing Hwy
243 alignment.
• Step 1a: However, this build concept was dismissed from further consideration because more extensive
maintenance is required for upkeep of the proposed tunnel’s security and operations. Additionally,
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pedestrians and cyclists would not be accommodated in the tunnel, meaning an additional asset such as
a multi-use trail would have to be maintained to preserve walkability and bikeability across the St. Croix
River.
3.1.5 Build Alternative C: New Hwy 243 Bridge on north side of existing structure
Build Alternative C includes constructing a new bridge parallel to the existing Hwy 243 Bridge. The Build
Alternative C alignment is along the north side of the existing structure. The existing Hwy 243 Bridge would be
removed.
Step 1 Evaluation: Build Concept C addresses the bridge condition need for this project as it includes completely
removing the existing Hwy 243 Bridge and constructing a new structure. This construction would include the
construction of a new bridge deck, superstructure, and substructure. This build concept has a 75-year plus
service life. Build Concept C is in proximity to the existing bridge and would be parallel to the existing Hwy 243
bridge.
• Step 1a: Build Concept C would require minimal maintenance and operating demands between
inspections because of its similarity to the current management requirements of the existing Hwy 243
Bridge. It would not impact the traffic flow in/around Osceola Landing and the Village of Osceola.
Step 2 Evaluation: Build Alternative C would have less impact to roadway traffic with the crossing being closed
for approximately 9 to 10 months; however, bridge abutment constructability along steep grades at the
Wisconsin bluff could result in additional roadway traffic disruption. This build alternative would likely expand
the existing bluff cut and require construction of retaining walls along the north side of Hwy 243 to avoid
impacts to the Osceola Creek (also known as Cascade Creek) and the Wilke Glen/Cascade Falls Trail. Build
Alternative C addresses the secondary walkability/bikeability need for the project and has SEE impacts that are
relatively similar with the other alternatives.
Step 3 Evaluation: Build Alternative C requires two river accesses for bridge construction, which would include
retaining wall construction along the Hwy 243 approach at the St. Croix River shoreline. This build alternative
also requires one additional construction season for in-water work to remove the existing Hwy 243 Bridge. This
alternative is anticipated to result in minor property impacts.
Build Alternative C was eliminated from further consideration and will not be studied further. There is a higher
likelihood that this alternative would adversely impact the surrounding environment compared to the other
alternatives. Additionally, this build alternative has a greater construction duration, the greatest amount of bluff
disturbance, and would have lower visual ranking due to the construction of a retaining wall. Build Alternative C
also has greater impacts to wetlands, greater amount of tree clearing and ground disturbance, greater amount
of river bottom disturbance and higher potential for impacts to protected species. This alternative also has
greater permitting risks compared to the other alternatives.
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3.1.6 Build Alternative D: New Hwy 243 Bridge on south side of existing structure
Build Alternative D includes constructing a new bridge crossing parallel to the existing Hwy 243 Bridge. The Build
Alternative D alignment is along the south side of the existing structure. The existing Hwy 243 Bridge would be
removed.
Step 1 Evaluation: Build Concept D addresses the bridge condition need for this project as it includes completely
removing the existing Hwy 243 Bridge and constructing a new structure. This construction would include the
construction of a new bridge deck, superstructure, and substructure. This build concept has a 75-year plus
service life. Build Concept D is in proximity to the existing bridge and would be parallel to the existing Hwy 243
Bridge.
• Step 1a: Build Concept D would require minimal maintenance and operating demands between
inspections because of its similarity to the current management requirements of the existing Hwy 243
Bridge. It would not impact the traffic flow in/around Osceola Landing and the Village of Osceola.
Step 2 Evaluation: Build Alternative D would have less impact to roadway traffic with the crossing being closed
for approximately 9 to 10 months; however, bridge abutment constructability along steep grades at the
Wisconsin bluff could result in additional roadway traffic disruption. This build alternative would likely expand
the existing bluff cut and require construction of retaining walls along the north side of Hwy 243 to avoid
impacts to the Osceola Creek and the Wilke Glen/Cascade Falls Trail. This build alternative would have the least
amount of bluff volume impacts.
Step 3 Evaluation: Build Alternative D requires two river accesses for bridge construction, which would include
retaining wall construction along the Hwy 243 approach at the St. Croix River shoreline. This build alternative
also requires one additional construction season for in-water work to remove the existing Hwy 243 Bridge. This
alternative is anticipated to result in minor property impacts.
Build Alternative D was eliminated from further consideration and will not be studied further. There is a higher
likelihood that this alternative would adversely impact the surrounding environment compared to the other
alternatives. Additionally, this build alternative has a greater construction duration, the greatest amount of
disturbance to the South Bluff along the Wisconsin approach, and would have lower visual ranking due to the
construction of a retaining wall. Build Alternative D also has greater impacts to wetlands, greater amount of tree
clearing and ground disturbance, greater amount of river bottom disturbance and higher potential for impacts
to protected species. This alternative also has greater permitting risks compared to the recommended build
concept.3
3 Greater permitting risk was defined as the likelihood that a build alternative would not be authorized by regulatory agencies because of
greater social and/or environmental impacts when compared to other alternatives.
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3.2 Alternatives under Consideration, including the “No Build” Alternative
3.2.1 No Build Alternative
The No Build Alternative (or “do nothing” alternative) includes routine bridge maintenance activities on the
existing Hwy 243 Bridge. The existing bridge deck, superstructure, and piers would be maintained. The No Build
Alternative is included as required by NEPA. The No Build Alternative represents the baseline condition for the
project and serves as the basis for comparing the social, economic, and environmental impacts of other
alternatives.
Step 1/1a/2/3 Evaluation: The No Build Alternative does not address the primary bridge condition need for the
project. It does not address the long-term condition needs of the project and only temporarily extends the
service life of the Hwy 243 Bridge. The No Build Alternative is only considered further as it is required under
NEPA since it provides the baseline condition against which other build alternatives are evaluated.
3.2.2 Build Alternative B: New Hwy 243 Bridge on existing alignment
Build Alternative B includes removing the existing Hwy 243 Bridge and constructing a new bridge and approach
roadways along the existing alignment.
Step 1 Evaluation: Build Concept B addresses the bridge condition need for this project as it includes completely
removing the existing Hwy 243 Bridge and constructing a new structure. This construction would include the
construction of a new bridge deck, superstructure, and substructure. This build concept has a 75-year plus
service life. Build Concept B follows the existing Hwy 243 alignment.
• Step 1a: Build Concept B would require minimal maintenance and operating demands between
inspections because of its similarity to the current management requirements of the existing Hwy 243
Bridge. It would not impact the traffic flow in/around Osceola Landing and the Village of Osceola.
Step 2 Evaluation: Build Alternative B would have the largest impact to roadway traffic during construction, as it
would be interrupted for the entire 21 to 24-month construction period. This build alternative has the least
amount of bluff surface area impacts. Build Alternative B addresses the secondary walkability/bikeability needs
for the project and has SEE impacts that are relatively similar to the other build concepts.
Step 3 Evaluation: Build Alternative B requires the longest crossing closure time, but has the shortest overall
construction duration. This build alternative minimizes in-water impacts compared to the off-alignment
alternatives because one river access is required for bridge construction compared to two. This build alternative
also does not include a retaining wall at the shoreline. Build Alternative B minimizes the potential impacts to the
surrounding natural environment compared to the other build concepts. Additionally, this build concept avoids
right of way acquisition.
Build Alternative B was identified as the Preferred Alternative for the Hwy 243 Osceola Bridge Project. This
alternative addresses the primary and secondary needs of the project. The Preferred Alternative addresses the
primary bridge conditions need of the project. The Preferred Alternative includes construction of a new bridge
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across the St. Croix River with a 75-year service life. The Preferred Alternative improves NBI condition ratings
compared to the No Build Alternative and provides a reliable river crossing. The Preferred Alternative also
addresses the secondary walkability/bikeability needs of the project. The Preferred Alternative includes a
pedestrian and bicycle sidepath on the north side of Hwy 243 across the St. Croix River, connecting Osceola
Landing to the Village of Osceola.
This build alternative additionally provides the opportunity to improve ecological and floodplain connectivity at
the existing Minnesota causeway. Build Alternative B would minimize in-water impacts, impacts to the
Wisconsin bluff, wetland impacts, protected species impacts, park impacts, visual impacts, and in-water
construction. This alternative also would have the least amount of river bottom disturbance, the least amount of
tree removal, and the least amount of ground disturbance. Build Alternative B would not require any relocations
and the preliminary construction limits are within the existing right of way.
3.3 Benefit Cost Analysis
The objective of a benefit-cost analysis (BCA) is to bring all the direct effects of a transportation investment into
a common measure (dollars), and to account for the fact that benefits accrue over an extended period while
costs are incurred primarily in the initial years. The primary elements that can be monetized are travel time,
changes in vehicle operating costs, vehicle crashes, capital costs, remaining capital value, and maintenance
costs. The BCA can provide an indication of the economic desirability of an alternative, but decision-makers
must weigh the results against other considerations, effects, and impacts of the project.
The BCA provides an indication of the economic desirability of a scenario, but results must be weighed by
decision-makers along with the assessment of other effects and impacts. Projects are considered cost-effective
if the benefit-cost ratio is at least 1.0. The larger the ratio number, the greater the benefits per unit cost. The
BCA for the project was based on preliminary cost estimates for the prestressed girder bridge type. The
benefit/cost ratio for the Hwy 243 Osceola Bridge Project was 11.69 compared to the No Build Alternative. The
final BCA memorandum is in APPENDIX O (Benefit-Cost Analysis Memo).
3.4 Bridge Type Study
The main objective of a bridge type study is to evaluate bridge concepts suitable for a replacement bridge on the
existing alignment and to provide a recommended bridge structure type. For purposes of this study, ‘structure
type’ includes both material type used for the superstructure (e.g. steel, prestressed concrete, etc.), as well as
the configuration/location of substructure elements. A secondary purpose of this study is to evaluate methods
that could be employed to reduce the time the bridge is closed to traffic and/or minimize the duration of
impacts within the river.
The selection of a recommended bridge type and configuration used a four-step process.
1. Step 1 - Develop Evaluation Criteria: Evaluation criteria were developed to compare impacts (both
positive and negative) that each alternative had to the project, stakeholders, and the environment.
Criteria were initially proposed to the Project Management Team and refined based on input from
stakeholders and regulatory agencies.
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2. Step 2 - Develop a List of Bridge Alternatives: A list of potential bridge types, including structure type,
substructure layout, and existing element reuse were identified. The initial bridge types were screened
and bridge types that were not practical for this river crossing location were dismissed from further
evaluation. The remaining bridge types were carried forward for further evaluation in Step 3.
3. Step 3 - Evaluate Alternatives: A general plan and profile was developed for remaining bridge types from
Step 2, including identifying pier placement in the St. Croix River. Evaluation matrices describing the
impacts for each bridge type were completed. Impact rankings (low, medium, high impacts) were
identified for evaluation criteria.
4. Step 4 - Provide a Recommended Bridge Type: The impacts of each bridge type were compared against
one another, and a recommended bridge type was identified.
The study identified and evaluated eight bridge type alternatives. An overall assessment of each alternative can
be found in Table 3-1. Overall Assessment of Alternatives in the Bridge Type Study. After review of the Bridge
Type Study Matrix, coordination with stakeholders, and consultation with regulatory agencies (Federal Hwy
Administration, National Parks Service, Minnesota and Wisconsin Departments of Natural Resources, etc.),
Alternative B1, 4-span Prestressed Concrete Beams, was identified as the preferred alternative bridge type.
A copy of the Bridge Type Study can be found in APPENDIX D (Bridge Type Study).
Table 3-1. Overall Assessment of Alternatives in the Bridge Type Study
Alternative Max Span
Length(s)
# of
Spans
# of
Piers Overall Assessment
A1 3-Span Steel Plate
Girders 275-ft ± 3 2
Moderate Impact: Low constructability
risk, no limitation to accelerated
construction techniques, provides
benefits to navigation clearances and
hydraulics. Moderate impacts to
schedule (girder lead time),
environmental considerations, and
future maintenance.
A1.1 3-Span Steel Plate
Girders 260-ft ± 3 2
A2 2-Span Steel Plate
Girders 334-ft ± 2 1
High Impact: Deep superstructure with
a pier centered in the river not
desirable. High construction costs.
B1 4-Span Prestressed
Concrete Beams 184-ft ± 4 3
Recommended Alternative: Prestressed
concrete beams are the preferred
structure type in MN & WI due to cost
and ease of inspection/future
maintenance. Low impacts to
environmental considerations. Moves
pier away from Osceola Creek.
Moderate constructability risk due to
heavy girders can be mitigated with
larger cranes and additional temporary
causeway on the WI riverbank during
construction. Temporary causeway(s)
will be removed before the end of
construction.
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Alternative Max Span
Length(s)
# of
Spans
# of
Piers Overall Assessment
B2 5-Span Prestressed
Concrete Beams 200-ft ± 5 4
High Impact: Requires 3 piers in the
river with a pier closer to Osceola Creek.
Moderate environmental impacts due
to large girder depth and piers closer
mussel habitat
B3 3-Span Prestressed
Concrete Beams 223-ft ± 3 2
Eliminated from Consideration: Current
hauling equipment does not have the
capacity for delivering a prestressed
beam >200-ft long.
C1 3-Span Continuous PT
Spliced Conc. 260-ft ± 3 2
High Impact: Longest traffic closure
with limited opportunities to accelerate
construction. Highest cost of all
alternatives. Moderate environmental
impacts due to piers closer to
riverbanks.
C2 3-Simple Span PT
Spliced Conc. 223-ft ± 3 2
Eliminated from Consideration: No
measurable benefits compared to
continuous structure.
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4. SOCIAL, ECONOMIC AND ENVIRONMENTAL IMPACTS
This section discusses the environmental impacts of the Preferred Alternative identified in the Alternatives
section. It contains two sub-sections;
- State EAW
- Additional Federal Issues
The EAW is a standard format used in Minnesota for environmental review of projects meeting certain
thresholds at Minnesota Rule 4410.4300. Federal environmental regulations not addressed on the EAW are
addressed in separate sub-section.
December 2022 version
4.1 Environmental Assessment Worksheet
This most recent EAW form and guidance documents are available at the Environmental Quality Board’s
website at: https://www.eqb.state.mn.us/. The EAW form provides information about a project that may
have the potential for significant environmental effects. Guidance documents provide additional detail and
links to resources for completing the EAW form.
Cumulative potential effects can either be addressed under each applicable EAW Item or can be
addressed collectively under EAW Item 21.
Note to reviewers: Comments must be submitted to the RGU during the 30-day comment period
following notice of the EAW in the EQB Monitor. Comments should address the accuracy and
completeness of information, potential impacts that warrant further investigation and the need for an
EIS.
4.1.1 Project Title
Hwy 243 Osceola Bridge Project (MnDOT State Project (SP) 1311-06, WisDOT Project ID 8417-00-76)
4.1.2 Proposer
Minnesota Department of Transportation
Contact person: Dmitry Tomasevich
Title: MnDOT Project Manager
Address: 1500 County Road B2 W
City, State, ZIP: Roseville, MN 55113
Phone: (651) 245-4406
Fax: N/A
Email: Dmitry.tomasevich@state.mn.us
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4.1.3 Responsible Governmental Unit (RGU)
Minnesota Department of Transportation
Contact person: Dmitry Tomasevich
Title: MnDOT Project Manager
Address: 1500 County Road B2 W
City, State, ZIP: Roseville, MN 55113
Phone: (651) 245-4406
Fax: N/A
Email: Dmitry.tomasevich@state.mn.us
4.1.4 Reason for EAW Preparation
Required: Discretionary:
EIS Scoping Citizen petition
Mandatory EAW RGU discretion
Proposer initiated
If EAW or EIS is mandatory, give EQB rule category subpart number(s) and name(s): Not applicable.
4.1.5 Project Location
Counties: Chisago County, Minnesota and Polk County, Wisconsin
City/Township: Franconia Township, Minnesota and Village of Osceola, Wisconsin
PLS Location (¼, ¼, Section, Township, Range): T33N-R19W-S27 (NW, NW)
Watershed (81 major watershed scale): Lower St. Croix River - Stillwater
GPS Coordinates: 45.32139373991882, -92.70994127171967 (approximate center)
Tax Parcel Numbers: Chisago Co: 040023900, 040023800, 040024700, 040023700, 040023600, 040024510,
040024300. Polk Co: 165005670100, 165005320000, 165005690100, 165005280100
At a minimum attach each of the following to the EAW:
• County map showing the general location of the project (see Figure 0-1 and Figure 0-2)
• U.S. Geological Survey 7.5 minute, 1:24,000 scale map indicating project boundaries (see Figure
4-1)
• Site plans showing all significant project and natural features
o Existing cover types within the project area: Figure 4-2
o Existing soil types within the project area: Figure 4-3
o Water resources within the project area: Figure 4-4
o Floodplain within the project area: Figure 4-5
• Pre-construction site plan and post-construction site plan (See Figure A1 in APPENDIX A
(Figures)).
• List of data sources, models, and other resources (from the Item-by-Item Guidance: Climate
Adaptation and Resilience or other) used for information about current Minnesota climate trends
and how climate change is anticipated to affect the general location of the project during the life of
the project (see Section 4.1.7 Climate Adaptation and Resilience).
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Figure 4-1. United States Geological Survey Topographical Map
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4.1.6 Project Description
4.1.6.1 Provide the brief project summary to be published in the EQB Monitor, (approximately 50
words).
MnDOT, in cooperation with WisDOT, proposes to replace the Hwy 243 Bridge over the St. Croix River in the St.
Croix National Scenic Riverway. Improvements include reconstruction of Hwy 243 from WIS-35 to 550 feet west
of the Osceola Landing entrance, constructing a westbound left turn lane to Osceola Landing, and constructing a
shared-use path on the north side of Hwy 243. Stormwater management improvements include constructing a
stormwater pond on the Minnesota side of the St. Croix River and a sump manhole and sediment basin along
the Wisconsin bluff.
4.1.6.2 Give a complete description of the proposed project and related new construction, including
infrastructure needs. If the project is an expansion include a description of the existing facility.
Emphasize: 1) construction, operation methods and features that will cause physical manipulation of
the environment or will produce waste, 2) modifications to existing equipment or industrial
processes, 3) significant demolition, removal, or remodeling of existing structures, and 4) timing and
duration of construction activities
1) Construction, operation methods and features that will cause physical manipulation of the environment or
will produce wastes
The project would involve the construction of a new bridge structure that will replace the existing Hwy 243
Bridge (MnDOT Bridge No. 6347, WisDOT No. Bridge B-48-224) over the St. Croix River National Scenic
Riverway. Proposed construction includes adding a westbound left turn lane at the Osceola Landing
entrance, located west of the river. The project involves the following elements that will cause physical
manipulation of the environment:
• The Hwy 243 Bridge would be reconstructed on the existing alignment; the bridge will be widened
from existing condition to accommodate a shared-use path on the north side of the bridge.
• A shared-use path is proposed on the north side of Hwy 243 (on and off the bridge), as well as a
shared-use path connection to the north side of Osceola Landing.
• Within Osceola Landing, the shared-use path/trail would continue (south of existing right of way) to
provide a crosswalk/sidewalk connection to the comfort area on the south side of the parking lot.
• The planned shared-use path would continue east of the river bridge and extend to WIS-35 (the eastern
limit of the project). The shared-use path on the Wisconsin side of the river will include ADA
considerations like buffers away from the roadway (where practicable), and bump outs (three side
landings on the north side of the shared-use path, to allow for a wheelchair accessible rest area as the
grade change steepens. Planned landings would be 205 to 210 feet apart.
• The pavement of Hwy 243 would be reconstructed throughout the project area (east and west of
the bridge reconstruction).
• A wet pond is proposed near the Osceola Landing entrance for stormwater and water quality
management, along with drainage improvements within existing right of way to the west of
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Osceola Landing. These improvements include management features to treat runoff from the
bridge and improve water quality.
• Minnesota wayside rest relocation, to be relocated from existing location to directly across from Osceola
Landing entrance (west of existing location).
• Addition of a pull off area on Hwy 243 on the Wisconsin side of the river.
• In-water work in the St. Croix River, including temporary causeway construction on each side of the
river.
• Temporary construction staging areas on each side of the river, adjacent to Hwy 243.
• Bridge construction will require the use of barges (in-water) and cranes (on-land).
• Pier construction would use cofferdams to contain construction impacts within the St. Croix River.
A comprehensive constructability review is ongoing with the development of this project. Construction
timeline/schedule, construction access, disturbance limits, and a recommendation were developed as part of
the constructability review and report APPENDIX E (Constructability Report).
The evaluation of construction access involved determining crane sizing and placement/staging, pontoon barge
feasibility, river water levels, temporary causeway assessment, and considerations for Wisconsin access due to
the bluffs near the Hwy 243 Bridge. After reviewing several constructability considerations, the project team’s
recommended approach includes sheet pile supported earthen causeways (likely from each side of the river for
temporary construction condition), pontoon barge operation in the main channel of the St. Croix River to
support demolition and construction of the new bridge, as well as transportation of materials and equipment to
the Wisconsin side of the river. Sheet pile supported temporary causeways are being considered because this
method reduces the causeway footprint compared to other methods. The northern Osceola Landing parking lot
would be used for construction staging/access which has involved active coordination with the NPS. The NPS
used an area south of the Osceola Landing entrance road for equipment and materials storage for construction
of the recent Osceola Landing Phase I Improvements Project. Because this area has been previously disturbed, it
is anticipated that the Hwy 243 Osceola Bridge Project will also use this area for construction equipment and
materials storage.
Recommendations also include excavation into the Wisconsin hillside adjacent to the Wisconsin bridge
abutment to facilitate crane placement for concrete beam installation of the bridge. There is also potential for
dredging to occur in the west side of the river, nearest the Osceola Landing parking lot, for launching of pontoon
barges. A detailed map of construction access areas and in-water impacts can be found at the end of APPENDIX
E (Constructability Report).
2) Modifications to existing equipment or industrial processes
The project would not modify existing equipment or industrial processes.
3) Significant demolition, removal, or remodel of existing structures
The proposed project would involve the demolition and removal of the existing Hwy 243 Bridge over the St.
Croix National Scenic Riverway, including removal of the bridge and the existing bridge deck, superstructure,
substructure, and bridge piers. New bridge piers, substructure, superstructure, and a new bridge deck would be
constructed in place of the removed bridge structures.
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The bridge deck and superstructure will be disassembled into manageable pieces using standard construction
practices. Temporary shoring may be required to support the bridge during removal. Dropping the existing
bridge deck and superstructure into the St. Croix River will not be allowed. The bridge abutments will be
removed using standard construction practices to an elevation below the ground surface. The use of explosives
for removal of the bridge deck and superstructure will not be allowed. All debris will be removed from the
project site.
The existing bridge piers will be removed from the St. Croix River. MnDOT and WisDOT will prepare a removal
plan for the existing bridge piers. The removal plan will identify all proposed methods for removal and best
management practices to be implemented during removal. The following measures will be implemented for
bridge pier removal:
• All required permits shall be granted prior to the start of removal operations in the St. Croix River.
• The use of explosives for bridge pier removal will not be allowed.
• The bridge piers shall be completely removed to a specified depth below the St. Croix River channel
bottom. This depth will be identified in coordination with permitting agencies (e.g., USACE, USGS).
• All fugitive dust emissions during the pier removal process shall be contained.
• No turbid and/or sediment laden water shall leave the project limits.
• Cofferdams shall be used for bridge pier removal. All rubble and debris shall be contained and removed.
• The contractor shall confirm the required removal depth and indicate any obstructions remaining in the
St. Croix River channel. Any obstructions remaining will be removed. This information shall be
documented and provided to MnDOT.
No existing building impacts are anticipated in the project. All existing structures would be preserved and/or
avoided.
The Minnesota state sign/monument would remain in its existing location.
4) Timing and duration of construction activities
Construction of the proposed Hwy 243 Osceola Bridge Project is anticipated to begin in Fall 2026 with the
procurement of causeway permits and materials. Bridge construction is planned to occur for two construction
seasons (2027 and 2028). The new bridge is anticipated to open in the fall of 2028. Restoration of construction
staging areas, including Osceola Landing improvements, would occur in 2029. A preliminary construction
schedule is provided in the Constructability Report in APPENDIX E (Constructability Report).
4.1.6.3 Project magnitude
Table 4-1 tabulates the Hwy 243 Osceola Project magnitude. This table is required as part of the EAW process
and document. Several parameters do not apply to a transportation project; therefore, they are not applicable.
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Table 4-1. Project Magnitude
Description Minnesota Magnitude Wisconsin Magnitude Total Magnitude
Total Project Acreage 5.64 2.61 8.25
Linear Project Length (miles) 0.4 0.28 0.68
Number and Type of
Residential Units
Not applicable Not applicable Not applicable
Residential building area (in
square feet)
Not applicable Not applicable Not applicable
Commercial building area (in
square feet)
Not applicable Not applicable Not applicable
Industrial building area (in
square feet)
Not applicable Not applicable Not applicable
Institutional building area (in
square feet)
Not applicable Not applicable Not applicable
Other uses – specify (in
square feet)
Not applicable Not applicable Not applicable
Structure height(s) Top elevation close to
existing
Top elevation close to
existing
Top elevation similar
to existing 4
4.1.6.4 Explain the project purpose; if the project will be carried out by a governmental unit, explain
the need for the project and identify its beneficiaries.
The purpose of this project is to address the bridge condition over the St. Croix River in the Hwy 243 corridor
between Washington/Chisago counties in Minnesota and the Village of Osceola in Wisconsin and address
pedestrian and bicycle comfort and mobility while minimizing impacts to the area’s sensitive resources.
4.1.6.5 Are future stages of this development including development on any other property planned
or likely to happen? If yes, briefly describe future stages, relationship to present project, timeline
and plans for environmental review.
No. Not applicable to the Hwy 243 Osceola Bridge Project.
4.1.6.6 Is this project a subsequent stage of an earlier project? If yes, briefly describe the past
development, timeline and any past environmental review.
No. Not applicable to the Hwy 243 Osceola Bridge Project.
4 The proposed bridge will have reduced structure depth and a reduced number of piers compared to the existing bridge. This will
increase both vertical and horizontal clearance beneath the bridge.
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4.1.7 Climate Adaptation and Resilience
4.1.7.1 Describe the climate trends in the general location of the project (see guidance:
https://www.eqb.state.mn.us/sites/eqb/files/documents/2023%20EAW%20Climate%20Guidance.pdf)
and how climate change is anticipated to affect that location during the life of the project.
Current and predicted future deviations in Minnesota and Wisconsin’s microclimates include higher intensity
rainfall events, more localized flooding, more frequent (recurrent) freeze/thaw cycles, lack of snow cover,
extreme heat events, and droughts have the likelihood to impair infrastructure and create safety risks. For
transportation infrastructure, the two primary concerns are the projected changes in temperature and rainfall
intensity.
All the data sources reviewed gave high probabilities for increased temperatures and increased precipitation
over the next 20 years, resulting in increased flooding and stormwater management concerns, as well as heat
waves. However, review of the flood factor mapping for the project area in Chisago County indicated an overall
minor-moderate risk of flooding. The increased rainfall intensity and frequency can affect stormwater
management systems and increase water pollution. Higher temperatures can also harm water quality. Data also
indicates a greater probability of drought periods, though these are not predicted to be as frequent as the
periods of increased precipitation. These shifts in weather patterns will affect vegetation and wildlife 9both
aquatic and terrestrial).
MnDOT has identified several potential negative effects of climate change on the state’s transportation system
and the need to adapt. Confidence is high to very high for the following impacts: heavy precipitation/flooding,
warmer winters, and new species ranges. Examples of negative effects include overtopping roads due to
flooding, damage to the highway, more ice-buildup and reduced pavement conditions, changes in roadside
vegetation mixes, and increases in invasive species.
The National Park Service’s Foundation Document for the St. Croix National Scenic Riverway (September 2017)
states the following regarding climate change:
“Increases in mean annual temperature (+3.5°F–5.5°F by 2070), slight increases in mean annual precipitation
(+3%–6% by 2070), increases in extreme heat events, and increases in storm frequency and intensity are
projected for the region due to climate change. These changes in climate will have far-reaching impacts on the
St. Croix and Namekagon Rivers, local aquifers, and aquatic environments at St. Croix National Scenic Riverway.
Impacts on terrestrial habitats are also expected. Changes in species composition, increases in wildfire frequency,
and increases in invasive species are possible, along with impacts (e.g., food and erosion events) on cultural
resources and facilities within the Riverway. Adapting to the impacts of climate change will require park
managers to continue to learn from the past, but be forward-looking, anticipating plausible and sometimes
unprecedented conditions based on observations from monitoring and projections from regional climate models.
The National Park Service is instructed to incorporate climate considerations in decision processes and
management planning as parks consider adaptation options that may deviate from traditional practices.”
Several climate predictions summarized below use Representative Concentration Pathways (RCPs), which are
greenhouse gas (GHG) concentration scenarios used by the Intergovernmental Panel on Climate Change. RCP 4.5
is an intermediate scenario in which emissions decline after peaking around 2040, and RCP 8.5 is a worst-case
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scenario in which emissions continue to rise through the 21st century.5 The Minnesota Climate Explorer tool was
used to obtain historical average and projected temperatures/precipitation based on different climate
projections.6
Temperature
The historical average temperature within Chisago County between 1900 and 1999 was approximately 42.4°F.
The historical temperature trend between 1900 and 1999 was a rise of approximately 0.17°F per decade.
Between 2003 and 2023, the annual average temperature rose to 44.3°F. The average annual temperature
within Chisago County is projected to continue to rise in the foreseeable future. Average annual temperature
under RCP 4.5 is projected to increase to 47.2°F from 2040 to 2059. From 2080 to 2099, this measurement is
projected to increase even further to 49.7°F under RCP 4.5 or 53.4°F under RCP 8.5.
Excessive Heat Events
A series of unusually hot days is referred to as an extreme heat event. Extreme heat events have occurred in
project area. Between 1950 and 2023, Chisago County experienced five (5) excessive heat events which
occurred in 2011, 2016, two events in 2022, and 2023.7 Between 1950 and 2023, Polk County experienced two
(2) excessive heat events, which occurred in 2011 and in 2020.4 No deaths, injuries, property damage, or crop
damage were reported with any of the five events in Chisago County or Polk County. The severity and frequency
of excessive heat events are anticipated to increase due to climate change. These events are often intensified in
urban areas due to the urban heat island effect, which occurs when there is a high concentration of impervious
surfaces that absorb and re-release more heat from the sun than natural and green surfaces. This year, the
Village of Osceola is anticipated to experience 7 days with a “feels like” temperature of 100°F or above, and in
30 years the project area is anticipated to experience 14 days above 100°F, which would increase the potential
for an extreme heat event to occur.8
Freeze-Thaw Cycles
A freeze-thaw cycle occurs when air temperature drops low enough to freeze liquid water (32°F), then increases
enough for it to melt again.9 Freeze-thaw cycles typically occur most frequently in the wintertime, though have
the potential to occur at any time of year. In the project area, freeze-thaw events most frequently occur due to
warm daytime temperatures and cold nighttime temperatures during the early spring and late fall, although
they have the potential to occur at any time of the year. When rainwater or snowmelt drains into cracks in
concrete or pavement, the water begins to freeze and expand, causing small cracks to grow bigger. This
5 Minnesota Department of Natural Resources. Climate Explorer Metadata. Accessed in February 2024 and available at
https://www.dnr.state.mn.us/climate/climate-explorer-metadata.html.
6 Minnesota Department of Natural Resources. Minnesota Climate Explorer. Accessed in February 2024 and available at
https://arcgis.dnr.state.mn.us/ewr/climateexplorer/main/historical.
7 National Oceanic and Atmosphere Association. Storm Events Database -Excessive Heat Events. Accessed in March 2024 and available at
https://www.ncdc.noaa.gov/stormevents/.
8 Risk Factor. Does Osceola Have Heat Risk? Accessed in March 2024 and available at https://riskfactor.com/city/osceola-
wi/5560450_fsid/heat
9 GLISA. Freeze-Thaw Cycles. Accessed in March 2024 and available at https://glisa.umich.edu/resources-tools/climate-impacts/freeze-
thaw-cycles/.
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phenomenon can cause damage to infrastructure. As reported in the research report Effect of Warmer
Minnesota Winters on Freeze-Thaw Cycles, the variation in freeze-thaw events for the 40-year period between
1941 and 1980 as compared to the 40-year period between 1981 and 2020 is minimal (a less than five event
difference); however, freeze-thaw cycles typically increase during warmer winter periods.10
Precipitation
Annual Precipitation
The historical average annual precipitation within Chisago County between 1900 and 1999 was approximately
29.3 inches. Between 2003 and 2023, the annual average precipitation increased to 30.5 inches. The average
annual precipitation within Chisago County is projected to continue to rise in the foreseeable future. In 2040-
2059, average annual precipitation under RCP 4.5 is projected to increase to 32.0 inches. In 2080-2099, this
metric is predicted to grow even higher to 32.9 inches under RCP 4.5 or 34.9 inches under RCP 8.5.
Extreme Rainfall Events
Projections of intensifying storms are different from those of average conditions. Depth of precipitation,
intensity of rainfall, and rainfall/storms duration are factors related to the predicted changes in Minnesota and
Wisconsin’s climate. While these factors are mostly independent, they could be correlated in their effects on
hydrologic and hydraulic systems. According to the Minnesota Climate and Health Report, when comparing the
1960s decade to the 2000s, the number of storms discharging three inches of rainfall or more increased 71
percent.11 Among climate scientists, it is widely accepted that along with increased precipitation depth and
intensity, storm duration may also increase. According to the Climate Change Scenario Map from the EPA, the
100-year storm in the project area is projected to increase 2.4 percent to 13.6 percent by 2035 and 4.7 percent
to 26.5 percent by 2060.12
Stormwater Management Infrastructure and Design
Intensifying storms introduce potentially critical challenges in water resources management and drainage
infrastructure function and protection. Increased precipitation depth, rainfall intensity, and storm duration are
anticipated to affect drainage infrastructure in cases where existing storm sewer systems and stormwater
management areas have been designed to previous standards of less extreme events. Temporary flooding on
roadways and bridges and exceeding storage capacity of stormwater management areas and systems could take
place due to any (or a combination) of the issues discussed above.
10 Minnesota Department of Transportation. Effect of Warmer Minnesota Winters on Freeze-Thaw Cycles (2022). Available at
https://mdl.mndot.gov/items/202204.
11 Minnesota Department of Health. Minnesota Climate and Health Profile Report (2015). Accessed in March 2024 and available at
https://www.health.state.mn.us/communities/environment/climate/docs/mnprofile2015.pdf.
12 Environmental Protection Agency. CREAT Climate Change Scenarios Projection Map. Accessed in March 2024 and available at
https://epa.maps.arcgis.com/apps/MapSeries/index.html?appid=3805293158d54846a29f750d63c6890e&platform%23map.
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River Levels
Like the discussion of localized drainage infrastructure, it should also be expected that small-scale regional
rainfall events with factors of differing depth, intensity, and duration would impact riverine flooding upstream
and downstream of the project area; however, near the Hwy 243 Bridge, the floodplain widens west into
Minnesota, where large wetland complexes can help store high volumes of stormwater in the event of flooding.
The effective Flood Insurance Rate Maps (FIRM) and Flood Insurance Study (FIS) from the Federal Emergency
Management Agency (FEMA) report the 100-year (i.e., 1-percent annual flood chance) floodplain elevation in
the project area is at an elevation of 703.6 feet and the 500-year (i.e., 0.2-percent annual flood chance) is at an
elevation of 707.3 feet (see Section 4.1.12 for details of FEMA floodplain).
Existing conditions modeling was completed as part of the hydraulic analysis for the project. Hydraulic modeling
analysis of the existing crossing indicates that the road overtops during flooding events equal to and larger than
the 500-year storm event.
St. Croix River levels are highly variable in the project area. Flood events are common in the spring, and river
levels will decrease throughout the remainder of the summer and fall. For example, flood conditions in Spring
2023 inundated Osceola Landing and the site was temporary closed. By the end of Summer 2023, river levels
were low as the region experienced drought conditions.
A singular rainfall event in the St. Croix River Watershed is expected to have an effect on water levels of the St.
Croix River within the project area, depending on the magnitude and duration of the rainfall. All runoff in the
project area and surrounding watershed is destined for the river. River levels often increase following a rainfall
event, though those increases slowly subside over time as runoff is transported downstream and leveled off.
River levels are also impacted by periods of drought in the region. Generally, the levels of the St. Croix River
react to weather and climate patterns in the area. Large-scale regional rainfall and snowmelt events occurring
over several years are expected to have a larger and longer-term impact on average river levels. Although there
is inherent uncertainty, research suggests large-scale regional rainfall and snowmelt events occurring over
several years could impact river levels.
In general, the proposed Hwy 243 Bridge will follow the existing bridge profile. The existing bridge includes a 20-
foot-deep superstructure. The proposed Hwy 243 Bridge includes a shallower superstructure, increasing vertical
clearance under the bridge by more than 10 feet. The reduction in bridge superstructure depth minimizes
potential risks for river level fluctuations to impact the Hwy 243 Bridge as noted in
Table 4-2.
Figure 4-5. FEMA Floodplain FIRMette illustrates locations that are currently below an elevation of 703.6 feet
(the base/100-year flood elevation), which shows the locations within and near the project area that would be
most immediately affected by rising St. Croix River water elevations. With the exception of Osceola Landing,
there is minimal development within the floodplain in the project area that would immediately be affected by
flooding.
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4.7.1.2 For each Resource Category in the table below: Describe how the project’s proposed
activities and how the project’s design will interact with those climate trends. Describe proposed
adaptations to address the project effects identified.
Table 4-2. Climate Considerations and Adaptations discusses climate considerations and adaptations, based on
typical resource categories for a transportation project. Due to the location and design of this project, climate
impacts are not anticipated.
Table 4-2. Climate Considerations and Adaptations
Resource Category Climate Considerations Project Information Adaptations
Project Design Existing risks and
vulnerabilities associated
with the increased
frequency and intensity
of rainfall events include
transportation
infrastructure damage,
road closures, washouts,
slope collapses, and
other related failures.
Temporary
increased flooding
on roadways and
bridges could occur
due to limited
conveyance capacity
of drainage systems
and storage capacity
of stormwater
management areas
being surpassed.
A “resiliency check” storm event
(i.e., 15-percent increase in the
current Atlas 14 depth and intensity
values) will be used to assess
climate resilience on the project.
The resiliency check storm may not
factor into stormwater management
area, culvert or storm sewer sizing;
instead, it would be used to assess
risks of infrastructure damage due
to rainfall intensity above the
current design storms, and then
recommend locations for
reinforcement or other solutions to
improve climate resiliency. This
vulnerability assessment will help
improve the climate resiliency of the
project to extreme storms.
Project Design Risks and vulnerabilities
associated with warming
temperatures and
increased frequency of
excessive heat days and
freeze-thaw events
include increased
pavement deterioration
like cracking and road
buckling. Additionally,
extreme heat events and
cracked or icy pavements
can produce hazards and
These impacts may
affect the lifespan
and maintenance of
a project. According
to MnDOT, more
frequent (repeated)
freeze-thaw cycles
associated with
climate change will
result in destructive
impacts on
pavement. High
road surface
MnDOT is studying the effects of
increased freeze-thaw cycles on
pavement; as design standards are
updated to address negative
impacts, those standards would be
implemented on projects at a
statewide level. Freeze-thaw
tolerant designs and materials are
being used, therefore increases in
freeze-thaw cycles are unlikely to
have an impact.
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Resource Category Climate Considerations Project Information Adaptations
challenges for
accessibility (people
walking, rolling, or
biking).
temperatures
associated with
these events can
threaten the
integrity of bridge
infrastructure,
including creating
additional stress on
joints and
potentially causing
pavement to buckle.
Project Design Uncertain long-term
trends in river elevations
of the St. Croix
Through
coordination with
the USCG, it is
known that the
proposed bridge
must meet or
exceed the vertical
and horizontal
clearances of the
existing bridge.
Increases in St. Croix
River levels would
directly affect
navigation under
the proposed
bridge, however,
there is no
commercial or
industrial navigation
on the river; traffic
is limited to kayaks,
canoes, and small
boats.
The proposed bridge design will
result in vertical and lateral
clearances that will exceed the
existing clearances, making the
bridge more adaptable in high-rise
conditions. Additional coordination
with the USCG will be conducted as
part of the Section 9 permitting
process. A summary of the St. Croix
River water level considerations and
resulting impacts to vertical
clearance will be provided in the
final bridge hydraulics letter.
Land Use No critical facilities (i.e.
facilities necessary for
public health and safety,
those storing hazardous
materials, or those with
housing occupants who
may be insufficiently
mobile) are located
Not Applicable Not Applicable
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Resource Category Climate Considerations Project Information Adaptations
within or near the project
area.
Water Resources Current climate trends
and projected climate
change near the project
area could influence
water resources. Water
resources near and
within the project area
are likely to increase in
temperature and volume
due to warmer weather
and increasing runoff
from rainfall events.
There could be localized
evaporation and water
available when it rains,
causing increased flood
risk. More intense storm
events with higher,
severe rainfall
magnitudes are
predicted, with will
require drainage systems
to be appropriately
maintained to adapt to
the increase in
stormwater levels.
The project is
anticipated to
disturb
approximately 8.5
acres and increase
impervious surface
by approximately
1.1 acres for the
entirety of the
project (both states
combined).
Stormsewer
infrastructure and a
new stormwater
pond will be added
to the project to
convey runoff to
stormwater
management areas.
Each of the planned stormwater
management areas (see Section
4.1.12.2 Describe effects from
project activities on water resources
and measures to minimize or
mitigate the effects below.) are
located above an elevation of 703
feet. Stormwater management
areas could be designed with
consideration to the possible
increased tailwater effect of river
level rises. Each of the stormwater
management locations were
prioritized near reasonable outlet
locations with the goal of minimizing
the need for drainage structures
suspended from the bridge which
could become overburdened during
heavy rainfall events. MnDOT will
run a resiliency storm check, as
described above, to identify other
potential impacts to the proposed
storm sewer system. Using native
plants and perennials for
landscaping within stormwater
management areas would help
increase vegetative uptake of water
and this is planned for post-
construction.
Contamination/
Hazardous
Materials/Wastes
More intense rainfall
events and more
frequent freeze/thaw
cycles could damage
infrastructure and
create situations that
result in accidental
spills.
The proposed
project is not
anticipated to
generate hazardous
waste or materials.
On-site storage and
use of petroleum
products for
construction
equipment.
A spill prevention plan will be
prepared and implemented to
address any accidental spills that
occur during construction.
Accidental spills that occur on the
bridge deck after construction
would be discharged to the new
stormwater pond.
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Resource Category Climate Considerations Project Information Adaptations
Fish, Wildlife, Plant
Communities, and
Sensitive Ecological
Resources (Rare
Features)
Current Minnesota and
Wisconsin climate trends
and projected climate
change in the general
location of the project
could influence the local
species and suitable
habitat. Suitable habitat
for species may become
unsuitable due to
increased temperature
and increased runoff.
The project would
not introduce a new
barrier to wildlife
passage or fish
migration, nor
prevent movement
of species migrating
due to shifts in
suitable habitat
range. The project
will include a new
stormwater pond,
treating stormwater
runoff and
improving water
quality for mussels.
Wildlife crossing locations and
structures are planned and will be
implemented with the project, west
of the St. Croix River in Minnesota
(see Section 4.1.14.4 Avoidance,
Minimization, and/or Mitigation –
Turtles for more information).
4.1.8 Cover Types
4.1.8.1 Estimated Acreage
Estimate the acreage of the site with each of the following cover types before and after development:
Table 4-3 summarizes the before and after acreages of the cover types analysis conducted for the project.
Table 4-3. Cover Types13
Cover Types Before (acres) After (acres)
Wetlands and shallow lakes (<2 meters deep)14 0.28 0
Deep lakes (>2 meters deep) 0 0
Wooded/forest 4.58 0
Rivers/streams 0.56 0.56
Brush/Grassland 0 0
Cropland 0 0
Livestock rangeland/pastureland 0 0
Lawn/landscaping 1.30 4.97
13 The “Before” and “After” area totals listed in the table above are preliminary estimates based on existing land cover data and
preliminary design files and are subject to change through more detailed design and construction. Note “Before” and “After” acreage
totals may not equal the sum of individual cover types due to factors like variability in data availability and rounding.
14 Wetlands and wooded areas lost but not converted into additional impervious surface or stormwater pond are assumed to be
landscaping/vegetated roadside.
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Cover Types Before (acres) After (acres)
Green infrastructure TOTAL (from table below*) 0 0
Impervious surface 2.89 3.85
Stormwater Pond (wet sedimentation basin) 0 0.23
Other (describe) 0 0
TOTAL 9.61 9.61
Table 4-4 summarizes before and after acreages of green infrastructure.
Table 4-4. Green Infrastructure
Green Infrastructure Before (acres) After (acres)
Constructed infiltration systems (infiltration
basins/infiltration trenches/rainwater
gardens/bioretention areas without underdrains/swales
with impermeable check dams)
N/A N/A
Constructed tree trenches and tree boxes N/A N/A
Constructed wetlands N/A N/A
Constructed green roofs N/A N/A
Constructed permeable pavements N/A N/A
Other (describe) N/A N/A
TOTAL N/A N/A
Table 4-5 tabulates information on tree removal proposed with the project. Approximately ninety percent of the
tree canopy within the preliminary construction limits would be removed, however, a landscaping plan is being
developed to mitigate the tree removal.
Table 4-5. Tree Removal
Trees Percent Number
Percent tree canopy removed (within construction limits) or
number of mature trees removed during development
90% Up to 5.0 acres
Number of new trees planted (planned) See below See below
The highway in the Minnesota approach area descends the bluff and then is elevated above the adjacent flood
plain to the north and the Osceola Landing site to the south. The reconstruction of the highway, bridge, and
trails will impact the existing vegetation at the margins of the right of way. Planned revegetation includes native
seeding and a mix of native trees and shrubs on roadway embankments. Over time, these will mature and create
a framed view of the river crossing and buffer the Osceola Landing site. Clear sight lines to the Minnesota State
Entry Sign at the wayside will be maintained. Clearances at roadway margins for sight lines and snow clearing
will also be followed.
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The terrain in the Wisconsin approach area is more dramatic with a steep bluff on the south side and deep
ravine on the north side. Avoidance of impacts to the slope and existing vegetation on the north side was a key
driver of the proposed highway design and layout. Limited pockets of revegetation with native trees and shrubs
are planned at the east abutment area and near the east end of the project to blend in with the surroundings.
Clear sight lines to the Village of Osceola Entrance Sign will be maintained.
The complete Visual Quality Manual (VQM) with a detailed landscaping plan can be requested from the MnDOT
Project Manager (See contact information in Section 4.1.2 Proposer). Environmental commitments regarding
vegetation are also included in the Environmental Management Plan (APPENDIX F (Environmental Management
Plan)).
The remainder of this page is intentionally left blank.
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Figure 4-2. Existing Cover Types
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4.1.9 Permits and Approvals Required
List all known local, state and federal permits, approvals, certifications and financial assistance for the project.
Include modifications of any existing permits, governmental review of plans and all direct and indirect forms of
public financial assistance including bond guarantees, Tax Increment Financing and infrastructure. All of these
final decisions are prohibited until all appropriate environmental reviews have been completed. See Minnesota
Rules, Chapter 4410.3100.
Table 4-6 is a comprehensive list of permits and approvals that will be applied for, are in progress, or have been
completed to ensure all applicable state and federal clearances will be met. MnDOT or WisDOT will be acquiring
the majority of the permits needed for this project.
Table 4-6. Permits and Approvals
Unit of Government Type of Permit or Approval Status
FHWA (Federal) Environmental Assessment Complete
FHWA (Federal) Finding of No Significant Impact
(anticipated) Pending
FHWA (Federal)
Section 4(f) de minimis determination (for
impacts to Lower St. Croix National Scenic
Riverway) (anticipated)
Pending
FHWA (Federal) Section 106 (Historic/Archaeological) Complete
USACE (Federal) Section 10/404 Permit (Individual Permit) To be applied for
USCG (Federal) Section 9 Permit To be applied for
USFWS (Federal) Endangered Species Section 7
Determination (Biological Opinion (BO))
BO under development
(pending)
USFWS (Federal) Migratory Bird Permit To be applied for, if
needed
USFWS (Federal) Bald Eagle Incidental Take Permit To be applied for, if
needed
NPS (Federal) Section 7(a) Evaluation and Determination Pending
NPS (Federal) Special Use Permit (Osceola Landing) To be applied for
Federal Aviation Administration (FAA)
(Federal)
Form FAA 7460-1 Notice of Proposed
Construction or Alteration To be applied for
MnDNR (Minnesota) Endangered/Threatened Species Incidental
Take Permits To be applied for
MnDNR (Minnesota) Public Waters Work Permit To be applied for
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Unit of Government Type of Permit or Approval Status
MnDNR (Minnesota) Water Appropriation Permit 15 To be applied for, if
needed
Minnesota Pollution Control Agency
(MPCA) (Minnesota) Section 401 Water Quality Certification To be applied for
MPCA (Minnesota)
National Pollution Discharge Elimination
System (NPDES) Construction Stormwater
Permit
To be applied for
MPCA (Minnesota) NPDES Sediment Dredge Permit To be applied for
MPCA (Minnesota) Response Action Plan/Construction
Contingency Plan (RAP/CCP) To be applied for
MPCA (Minnesota) No Association Determination To be applied for, if
needed
MnDOT (Minnesota) Wetland Conservation Act (WCA) Pending
MnDOT (Minnesota) Environmental Management Plan Pending
MnDOT (Minnesota) Environmental Assessment Worksheet Complete
MnDOT (Minnesota) EIS Need Decision Pending
Wisconsin Department of Natural
Resources (WisDNR) (Wisconsin) Final Letter of Concurrence To be applied for
WisDNR (Wisconsin)
Wisconsin Pollution Discharge Elimination
System (WPDES) Transportation
Construction General Permit
To be applied for
WisDNR (Wisconsin) Endangered/Threatened Species Incidental
Take Permits To be applied for
WisDNR (Wisconsin) WPDES Sediment Dredge Permit To be applied for
WisDNR (Wisconsin) Section 401 Water Quality Certification To be applied for
WisDNR (Wisconsin) Navigational Buoy Permit To be applied for
Cumulative potential effects may be considered and addressed in response to individual EAW Questions (Sections
4.1.10 to 4.1.20), or the RGU can address all cumulative potential effects in response to EAW Question 22
(Section 4.1.22). If addressing cumulative effects under individual items, make sure to include information
requested in EAW Question 21 (Section 4.1.21).
15 Contractor will acquire this permit.
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4.1.10 Land Use
4.1.10.1 Existing Land Use
Existing land use of the site as well as areas adjacent to and near the site, including parks and open space,
cemeteries, trails, prime or unique farmlands.
Existing land uses within the study area were identified through a review of 2023 aerial photography and county
parcel data. The study area contains existing roadways, bridge, roadside vegetation, and a variety of residential,
industrial, and commercial land uses. These land uses include:
• To the north: wetlands, parks, MnDNR land
• To the east: wetlands, St. Croix River, waterfront, Village of Osceola local parks
• To the west: parks, wetlands, NPS Osceola Boat Landing, low density residential
• To the south: NPS Osceola Boat Landing, St. Croix River, wetlands, parks
See APPENDIX M (Environmental Justice Analysis) for locations of environmental justice populations and
community facilities within the study area. Several trails (including Eagle Bluff Trail, Cascade Falls Trail, and Dr.
John Simenstad Trail on the Wisconsin side) are located under and adjacent to the existing bridge. There is also
an existing water trail (DNR State Water Trail on the St. Croix River). Parks within or near the study area include
the St. Croix National Scenic Riverway, National Park Service Land, Osceola Landing, and Minnesota DNR Land on
the Minnesota side, and Osceola Picnic Bluff, Geiger Brewery Park, Cascade Falls and Wilke Glen Park, Gristmill
Park, Millpond Park, and Upper Millpond on the Wisconsin side. These recreational resources are depicted in
Figure 4-9. Information regarding these resources are further discussed in Section 4.2.7 Section 4(f) of the
USDOT Act of 1966
Based on the United States Geological Survey (USGS) National Map and review of Google Maps satellite imagery
(2023), there are no cemeteries located within or adjacent to the study area.
According to the Natural Resources Conservation Service (NRCS) Web Soil Survey, of the four soil types within
the construction limits, none are classified as prime farmland or farmland of statewide importance.
4.1.10.2 Planned Land Use
Plans. Describe planned land use as identified in comprehensive plans (if available) and any other applicable plan
for land use, water, or resources management by a local, regional, state, or federal agency.
The following planning documents were reviewed for their relation to project area:
• Village of Osceola Comprehensive Plan, 2009-2029 (November 10, 2009)16
16 Village of Osceola. 2009-2029 Comprehensive Plan. Accessed in December 2023 and available at myosceola.com/wp-
content/uploads/2023/10/Osceola_Comprehensive_Plan_2009-2019.pdf.
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• Chisago County Comprehensive Plan, 2016-2026 (September 20, 2017)17
• Polk County Comprehensive Plan, 2009-2029 (October 20, 2009)18
• Wisconsin Connections 2030 Long Range Multi-Modal Transportation Plan (October 2009)19
• Minnesota Statewide Multimodal Transportation Plan (2022)20
• St. Croix National Scenic Riverway Comprehensive River Management Plan (Anticipated 2025)21
Village of Osceola Comprehensive Plan, 2009-2029 (2009)
Village of Osceola Comprehensive Plan is the Village of Osceola’s comprehensive plan that was adopted in 2009.
This plan’s overall goal is to “promote and protect the health, safety, economy, appearance, and welfare of the
Village by balancing growth with the preservation of our social and natural resources.”
This plan defines a range of land uses within the study area. This plan calls for Park and Recreation, Urban
Single-Family Residential, and Central Business District Zoning Districts (or Airport, Park, Single Family, and
Commercial Uses) within the project area, as defined below. According to the comprehensive plan, it is
important for land uses to promote the economy, respect natural, cultural, and agricultural resources, and to
foster a small town atmosphere. This plan does not make specific recommendations relevant to the Hwy
243Bridge.
• Park and Recreation (PR): The Park and Recreation District is intended to provide for areas where the
park and recreational needs, both public and private, of the populace can be met without undue
disturbance of natural resources and uses of other adjacent zoning districts. The PR District is further
intended to include both public and private open space (including stormwater retention/detention
areas) and recreation facilities. The various requirements of the PR District are established to increase
the compatibility of park and recreational uses with the character of the Village as set forth in the Village
of Osceola Comprehensive Plan and components thereof. The area and bulk requirements of the PR
District are intended to permit development that enhances and protects the open space character of the
PR District. The PR District is intended to be served by public sanitary sewer and water supply facilities.
• Urban Single-Family Residential (R-U): The R-U District is intended to provide for single-family residential
development on lots of record within the original plat of the Village existing at the time of the adoption
of the Ordinance codified under this title. The R-U District is intended to be served by public sanitary
sewer and water supply facilities.
• Commercial Business District (CBD): The CBD District is intended to provide for the continuation of the
Village of Osceola's traditional central business district. The existing commercial activities are of a
17 Chisago County. Chisago County Comprehensive Plan. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/9483/Comprehensive-Plan-2017-PDF?bidId=
18 Polk County. 2009-2029 Comprehensive Plan (Element 8: Land Use). Accessed in December 2023 and available at
https://cms5.revize.com/revize/polk/Document%20_Center/Divisions%20and%20Departments/Environmental%20Services%20Divisio
n/Land%20Information%20Office/Comprehensive%20Plan/Polk%20County%20Comprehensive%20Plan%202009-
2029/PlanPolkCountyComprehensive20092029LandUse.pdf
19 Wisconsin Department of Transportation. Connections 2030: Statewide Long-Range Transportation Plan. Accessed in December 2023
and available at https://wisconsindot.gov/Documents/projects/multimodal/conn2030/c2030-full.pdf
20 Minnesota Department of Transportation. Statewide Multimodal Transportation Plan. Accessed in December 2023 and available at
https://minnesotago.org/final-plans/smtp-final-plan-2022
21 National Park Service. St. Croix National Scenic Riverway. Comprehensive River Management Planning. Accessed in October 2024 and
available at https://www.nps.gov/sacn/learn/management/comprehensive-river-management-plan.htm.
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general nature and have been characterized by on-street parking and loading and structures that abut
the street right-of-way or have small setbacks. While it is intended that the existing businesses be
continued at their present level of service, it is also intended that new buildings located in the CBD
District--to the extent possible--be required to provide for off-street parking and loading areas. The
requirements of the CBD District are further established to maintain the traditional central business
district characteristics of the Village of Osceola "downtown." The CBD District provides for an
arrangement of retail trade and service uses as well as other uses that are compatible in intensity,
function, and operation. The CBD District is designed to prevent land and structures in the CBD District
from becoming nonconforming as they would if placed under different, more suburban-oriented, zoning
classifications. The CBD District also provides for the minor infilling of vacant or redevelopment areas
within the CBD District consistent with this planned and the established character of the Village of
Osceola "downtown." It is not intended to create additional CBD Districts of this type elsewhere in the
community. The CBD District is intended to be served by public sanitary sewer and water supply
facilities.
Chisago County Comprehensive Plan (2017)
The Chisago County Comprehensive Plan, adopted September 20, 2017, identifies land use trends and influences
that may be important factors for future policy development. The Land Use Plan section includes goals and
policies aiming to establish a comprehensive growth management strategy for the county, recognize the
challenges and compatibility of present and future land use and strive for balance, plan for the growth of
residential development in the county, and plan for commercial and industrial development and growth. This
plan does not make specific recommendations relevant to the Hwy 243 Bridge.
Polk County Comprehensive Plan (2009)
The Polk County Comprehensive Plan, adopted on October 20, 2009, establishes a bottom-up approach. This
means that all of the local comprehensive plans were utilized in the creation of the Polk County Comprehensive
Plan. Therefore, the land uses within the study area fall under the Village of Osceola’s comprehensive plan. This
plan does not make specific recommendations relevant to the Hwy 243 Bridge.
Wisconsin Connections 2030 Long Range Multi-Modal Transportation Plan (2009)
Connections 2030 is Wisconsin’s statewide, long-range multimodal plan. The plan addresses all forms of
transportation, integrates transportation modes, and identifies policies and implementation priorities to aid
transportation decisionmakers when evaluating program and project priorities over the next 20 years. Policy
goals that are supported by the Hwy 243 Osceola Bridge Project include:
• Prioritize funding to address the physical condition, safety, operation, function, and connectivity of the
system’s structures, bridges, pavements, and interchanges.
• Work with the public, local governments, and the private sector to balance providing safe and efficient
travel on state highways with local access concerns.
This plan does not make any specific recommendations relevant to the Hwy 243 Bridge.
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Minnesota GO Statewide Multimodal Transportation Plan (2022)
Minnesota GO is Minnesota’s highest level policy plan for transportation and was last updated in 2022. It is a 20-
year plan based on the Minnesota DO Vision for a transportation system that maximizes the health of people,
the environment, and the economy. It provides objectives, performance measures, strategies and actions to
move Minnesota’s transportation system forward. Policy goals that are supported by this project are:
• To provide multimodal and intermodal transportation facilities and services to increase access for all
persons and businesses and to ensure economic well-being and quality of life without undue burden
placed on any community.
• To encourage tourism by providing appropriate transportation to Minnesota facilities designed to
attract tourists and to enhance the appeal, through transportation investments, of tourist destinations
across the state.
• To promote and increase bicycling and walking as a percentage of all trips as energy-efficient,
nonpolluting and healthy forms of transportation.
This plan does not make any specific recommendations relevant to the Hwy 243 Bridge.
St. Croix National Scenic Riverway Comprehensive River Management Plan (Anticipated 2025)
The NPS has initiated the planning process to inform future management of the St. Croix National Scenic
Riverway. The comprehensive river management plan will provide overall management and direction to protect
and enhance the outstandingly remarkable values (ORVs) of the St. Croix National Scenic Riverway. The
comprehensive river management plan process began in 2023 and is anticipated to be complete in 2025.
The draft St. Croix National Scenic Riverway Comprehensive River Management Plan was not available at the
time the EA/EAW for the Hwy 243 Osceola Bridge Project was developed.
4.1.10.3 Zoning
Zoning, including special districts or overlays such as shoreland, floodplain, wild and scenic rivers, critical area,
agricultural preserves, etc.
Existing Zoning
The Parcels located in Franconia Township are currently zoned as AG (Agricultural) and LO (Lower St. Croix
Overlay).22 The Parcels located in the Village of Osceola are currently zoned as CD (Conservancy), R-U (Urban
Single-Family), I-1 (Light Industrial), and B-1 (General Commercial).23 Any new development, redevelopment,
change in land use, or change in zoning is required to be consistent with the Chisago County and Village of
Osceola comprehensive plans.
22 Chisago County. Franconia Township Zoning Map. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/4398/Franconia-PDF.
23 Village of Osceola. Map 8-2: Existing Zoning Districts. Accessed in December 2023 and available at Village of Osceola Zoning Map
https://myosceola.com/wp-content/uploads/2023/09/osceola_zoning_map.pdf.
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Shoreland Overlay District
The Chisago County shoreland definition 24,25 includes lands within 1,000 feet from the ordinary high-water level
of a lake, pond, or flowage and 300 feet from a river or stream, or the landward extent of a floodplain
designated by ordinance on a river or stream, whichever is greater.26 The project lies within the LO district. This
applies to lands in Township 33, Tange 19, Section 27 Government Lots 1 and 4 and Section 28 Government Lots
1, 3, 4, 7, and part of Government Lot 2. No structure can be located nearer than two hundred (200) feet from
the ordinary high-water mark and not less than one hundred (100) feet from a bluff line.
The project is not within the Osceola or Polk County shoreland overlay district.27
FEMA National Flood Hazard
According to FEMA’s FIRM, the project is located within the FEMA 100-year floodplain. The floodplain program is
administered through local zoning within the Chisago County Flood Plain Ordinance 28 and the Village of Osceola
Floodplain Zoning Ordinance.29
Critical Areas
The St. Croix River is a critical area due to its designation as a National Wild and Scenic River.
4.1.10.4 Critical Facilities
If any critical facilities (i.e. facilities necessary for public health and safety, those storing hazardous materials, or
those with housing occupants who may be insufficiently mobile) are proposed in floodplain areas and other areas
identified as at risk for localized flooding, describe the risk potential considering changing precipitation and event
intensity.
The Hwy 243 Osceola Bridge Project would not propose any critical facilities within the FEMA 100-year
floodplain. All transportation facilities would be located at an elevation higher than the 100-year floodplain of
703.6 feet.
24 Chisago County. Chisago County Zoning Ordinance. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/14947/2020-Zoning-Code-Uncodified-Version.
25 Chisago County. Shoreland Management Ordinance. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/4204/Chisago-County-Shoreland-Management-Ordinance?bidId=.
26 The limits of shorelands may be reduced whenever the waters involved are bounded by topographic divides which extend landward
from the waters for lesser distances and when approved by the commissioner.
27 Polk County. Zoning Districts. Accessed in December 2023 and available at
https://cms5.revize.com/revize/polk/Document%20_Center/Divisions%20and%20Departments/Environmental%20Services%20Divisio
n/Maps/Zoning/ZoningDeptZoningDistricts.pdf
28 Chisago County. Flood Plain Ordinance. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/4203/2012-Flood-Plain-Ordinance?bidId=.
29 Village of Osceola. Article III Floodplain Zoning District. Accessed in December 2023 and available at
https://ecode360.com/9813671#9813671.
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4.1.10.5 Discuss the project’s compatibility with nearby land uses, zoning, and plans listed in Section
4.1.10 above, concentrating on implications for environmental effects.
The project is not anticipated to result in any significant change in land use within the limits of construction. It is
not anticipated to lead to the development of any large scale commercial, industrial, residential, or other
development. Access to existing land uses will not be changed, and if so, changes would not be significant. The
project is consistent with local and regional comprehensive plans.
4.1.10.6 Identify measures incorporated into the proposed project to mitigate any potential
incompatibility as discussed in Section 4.1.10.5 above and any risk potential.
Not applicable. The Hwy 243 Osceola Bridge Project is consistent with all local and regional comprehensive
plans.
4.1.11 Geology, Soils, and Topography/Land Forms
4.1.11.1 Geology
Describe the geology underlying the project area and identify and map any susceptible geologic features such as
sinkholes, shallow limestone formations, unconfined/shallow aquifers, or karst conditions. Discuss any limitations
of these features for the project and any effects the project could have on these features. Identify any project
designs or mitigation measures to address effects to geologic features.
On the Minnesota side of the project area, the geology includes floodplain alluvium, undivided bedrock, richfield
terrace, and ice-contact stratified deposit.30 On the Wisconsin side, the project area is underlain by outwash
sand, non-calcareous sandy loamy till (ground moraine and end moraine).31 The depth to bedrock throughout
the study area varies, ranging in depth from approximately 0-100 feet.32,33 The bedrock in the study area is
comprised of the Tunnel City Group, Jordan Sandstone, upper volcanic sequence, undivided sandstone with
some dolomite and shale, Prairie du Chien Group-Oneota Dolomite (surrounding area), and St. Lawrence
Formation (surrounding area).34,35 Depth to water table is approximately 0 to 50+ feet below the surface 36 in
Minnesota and 0 to 50 feet 37 in Wisconsin. The project construction area does not have any known karst
30 Chisago County. Surficial Geology Map. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/2248/Plate-3---Surficial-Geology?bidId=a
31 WisDNR. Surficial Deposits. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/2248/Plate-3---Surficial-Geology?bidId=
32 Chisago County. Geologic Atlas. Accessed in December 2023 and available at https://www.chisagocountymn.gov/294/Geologic-Atlas
33 Wisconsin Geological and Natural History Survey (WGNHS). Depth to Bedrock in Wisconsin. Accessed in December 2023 and available at
https://wgnhs.wisc.edu/catalog/publication/000376/resource/m051
34 WGNHS. Bedrock Geologic Map of Wisconsin. Accessed in December 2023 and available at
https://wgnhs.wisc.edu/catalog/publication/000390/resource/m078paper
35 Chisago County. Bedrock Geology. Accessed in December 2023 and available at
https://www.chisagocountymn.gov/DocumentCenter/View/2247/Plate-2---Bedrock-Geology?bidId=
36 Natural Resources Research Institute. Minnesota Natural Resource Atlas. Accessed in December 2023 and available at
https://mnatlas.org/gis-tool/?id=k_0279
37 WisDNR. GCSM – Water Table Depth. Accessed in April 2024 and available at https://data-wi-dnr.opendata.arcgis.com/datasets/wi-
dnr::gcsm-water-table-depth/explore
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features present within or near its limits based on MnDNR’s Karst Feature Inventory Points 38 and the USGS Land
Subsidence in the United States.39 Artesian groundwater was found in borings B-6 and B-7 at Pier 3 as well as
approximately the soil/bedrock interface.40 The artesian head pressure could reportedly be counter-balanced by
approximately 3 feet of casing extension above existing grade at the time of drilling. The contractor will develop
and adhere to an artesian conditions contingency plan.
4.1.11.2 Soils and Topography
Describe the soils on the site, giving NRCS (SCS) classifications and descriptions, including limitations of soils.
Describe topography, any special site conditions relating to erosion potential, soil stability or other soils
limitations, such as steep slopes, highly permeable soils. Provide estimated volume and acreage of soil
excavation and/or grading. Discuss impacts from project activities (distinguish between construction and
operational activities) related to soils and topography. Identify measures during and after project construction to
address soil limitations including stabilization, soil corrections or other measures. Erosion/sedimentation control
related to stormwater runoff should be addressed in response to Item 12 (Water Resources).
According to the NRCS Web Soil Survey, the project area is comprised of three different soil types (see Table 4-7.
Soil Types within the Project Area and Figure 4-3. Soil Types). The erosion hazard rating included in Table 4-7.
Soil Types within the Project Area indicates the hazard of soil loss from off-road areas after disturbance activities
that expose the soil surface. Approximately 29.4 percent of the study area has soil erosion hazards that are not
rated. In 57.6 percent of the study area, the soil erosion hazard is described as “slight,” meaning that erosion is
unlikely under ordinary climatic conditions. The remaining 13 percent of the study area is water and is not rated.
Table 4-7. Soil Types within the Project Area
Map Unit
Symbol Description Erosion
Hazard Percent of Study Area Acres
1068 Caryville sandy loam,
occasionally flooded Slight 57.6 5.3
Fa Fluvaquents Not rated 4.4 0.4
Us Udorthents, sandy Not rated 25.0 2.3
W Water - 13.0 1.1
Total - - 100 9.1
Topography within the study area varies from 690 feet in elevation in the portions of the project area near the
St. Croix River to 890 feet as one moves east or west of the river. The study area generally drains into the St.
Croix River.
A Stormwater Pollution Prevention Plan (SWPPP) would be developed for this project. All areas disturbed during
construction would be stabilized in accordance with the SWPPP and related permitting requirements. In areas
with steep slopes, special consideration would be given to prevent erosion during construction, such as erosion
38 MnDNR. Minnesota Regions Prone to Surface Karst Feature Development. Accessed in December 2023 and available at
https://files.dnr.state.mn.us/waters/groundwater_section/mapping/gw/gw01_report.pdf
39 USGS. Land Subsidence in the United States. Accessed in April 2024 and available at https://water.usgs.gov/ogw/pubs/fs00165/
40 Dan Brown and Associates. Foundation Analysis and Design Report. Accessed in May 2024 and available upon request from the MnDOT
Project Manager.
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control blankets and soil reinforcement. No impacts to soils or topography are anticipated once construction of
this project is complete. If there are any long-term remediation responsibilities for contaminated property
management, an appropriate plan would be developed through coordination with the MPCA (if in Minnesota) or
WisDNR (if in Wisconsin). See Section 4.1.13 Contamination/Hazardous Materials and Wastes and APPENDIX I
(Contaminated Properties) for information about contaminated properties investigation.
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Figure 4-3. Soil Types
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4.1.12 Water Resources
4.1.12.1 Describe surface water and groundwater features on or near the site
Surface water
Lakes, streams, wetlands, intermittent channels, and county/judicial ditches. Include any special designations
such as public waters, shoreland classification and floodway/floodplain, trout stream/lake, wildlife lakes,
migratory waterfowl feeding/resting lake, and outstanding resource value water. Include the presence of aquatic
invasive species and the water quality impairments or special designations listed on the current MPCA 303d
Impaired Waters List that are within 1 mile of the project. Include DNR Public Waters Inventory number(s), if any.
Figure 4-4 illustrates surface waters within approximately one mile of the study area. These include the St. Croix
National Wild and Scenic River and Osceola Creek, which discharges to the St. Croix River.
Wetlands
Wetlands in Minnesota and Wisconsin were delineated using Level 2 (i.e., field review) methodology in 2022 and
2023. Wetlands were delineated using the Level 2 routine on-site method set forth in the 1987 Corps of
Engineers Wetlands Delineation Manual and the USACE Northcentral Northeast Regional Supplement, Version
2.0 (the Delineation Manual). This method is required under both the federal Clean Water Act (CWA) and the
Minnesota WCA. The Wetland Assessment and Two-Part Finding in APPENDIX G (Wetland Assessment & Two-
Part Finding) contains additional details on methodology and permanent wetland impacts.
MnDNR Public Waters
The MnDNR regulates public waters in the state of Minnesota, which include all water basins and watercourses
that meet the criteria set forth in Minnesota Statutes, Section 103G.005, subd. 15 that are identified on Public
Water Inventory maps authorized by Minnesota Statutes, Section 103G.201. Public waters within the vicinity of
the project area includes the St. Croix River (105245) and an unnamed wetland (70717).
WisDNR Waterways and Public Waters
The WisDNR regulates navigable waterways in the state of Wisconsin. The WisDNR operates under the “Public
Trust Doctrine,” which is based on Article IX of the state constitution. Generally, a waterway is navigable if it can
float a small watercraft and has a defined bed and bank. Navigable waterways in the project area include the St.
Croix River (600090392) and Osceola Creek (600024435).
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Figure 4-4. Water Resources
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Impaired Waters
The MPCA’s 2022 impaired water’s list identifies the St. Croix River as an impaired water north of the project
area (from the Snake River to the Taylors Falls Dam). The Snake River to the Taylors Falls Dam stretch of the St.
Croix River was added to the impaired waters list in 1998 for mercury in fish tissue and in 2006, for PCBs in fish
tissue. The St. Croix River between the Taylors Falls Dam to Lake St. Croix has been on the Total Maximum Daily
Load (TMDL) list since 2006 for PCBs in fish tissue, in 2020 for nutrients, and in 2022 for perfluoro octane
sulfonate (PFOS) in fish tissue.
As noted in the WisDNR initial response letter (APPENDIX J (Agency Correspondence)), the portion of the St.
Croix River in the project area is a 303(d) listed waterbody. There is a fish consumption advisory for PCBs that is
likely associated with contaminated sediment in the Mississippi River.
MPCA Outstanding Resource Value Water
Minnesota Rules, part 7050.0335, designates Outstanding Resource Value Waters. The St. Croix River is a
designated Outstanding Resource Value Water (ORVW). Outstanding resource value waters classified as
"prohibited" and "restricted" have extra levels of protection above other waters to protect their unique natures.
These include high-quality waters and waters that have exceptional recreation, cultural, aesthetic, or scientific
value.41 The St. Croix River Is designated at “restricted” in the project area. Projects in Restricted ORVWs may be
required to apply for an Individual 401 Water Quality Certification review.
WI ASNRI Outstanding and Exceptional Resource Waters
Wisconsin’s Administrative Code, chapters NR 102.10 and NR 102.11, designates Outstanding and Exceptional
Resource Waters (ORWs/ERWs). The St. Croix River is a designated Outstanding Resource Water and Exceptional
Resource Water. ORW/ERW status identifies waters that have been determined to warrant additional protection
from the effects of pollution.
Coastal Zones
The project area is not within or adjacent to any coastal zones in either Minnesota or Wisconsin.
Floodplains
FEMA FIRMs and Flood Insurance Studies (FIS) were used to identify FEMA 100-year floodplains and floodways
within the project area. Panels 27025C0425D (effective date of April 17, 2012) and 55095C0504D (effective date
of September 16, 2011) were obtained and reviewed. According to the maps, a FEMA 100-year floodplain (i.e.,
1% annual flood chance) is located within the project area. This floodplain is associated with the St. Croix River
and has an established elevation of 703 feet in the National Geodetic Vertical Datum (NGVD) of 1929 at the Hwy
243 Bridge. FIS 55095CV000A for Polk County, WI and 27025CV000A for Chisago County, MN also both indicate
41 Minnesota Pollution Control Agency. Clean Water Act Section 401 water quality certifications. Accessed in March 2024 and available at
https://www.pca.state.mn.us/business-with-us/clean-water-act-section-401-water-quality-certifications
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a base flood elevation (BFE) of 703 feet and flow rate of 61,000 cubic feet per second (cfs) in the 100-year event
at the Hwy 243 Bridge. Figure 4-5 illustrates floodplains in the project area. There is no regulatory floodway in
the project area.
According to 44 CFR § 9.4, 100-year floodplain (also known as base floodplain) means the floodplain “for the
flood which has a one percent chance of being equaled or exceeded in any given year” and “floodway means
that portion of the floodplain which is effective in carrying flow, within which this carrying capacity must be
preserved and where the flood hazard is generally highest, i.e., where water depths and velocities are the
greatest. It is that area which provides for the discharge of the base flood so the cumulative increase in water
surface elevation is no more than one foot.”
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Figure 4-5. FEMA Floodplain FIRMette
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Groundwater
Aquifers, springs, seeps. Include: 1) depth to groundwater; 2) if project is within a Minnesota Department of
Health (MDH) wellhead protection area; 3) identification of any onsite and/or nearby wells, including unique
numbers and well logs if available. If there are no wells known on site or nearby, explain the methodology used
to determine this.
1) Depth to Groundwater
Regional groundwater flow direction in the vicinity of the project corridor is presumed to be toward the St. Croix
River, centrally located on the project corridor. Depth to groundwater is expected to be encountered less than
20 feet below ground surface (bgs) near the St. Croix River and on the eastern portion of the project corridor.42
Depth to groundwater is expected to be encountered between 25 and 50 feet bgs on the western portion of the
project corridor.43
2) Wellhead Protection Area
According to the MDH Source Water Protection Web Map Viewer,44 the project area in Minnesota is not located
within a Wellhead Protection Area or Drinking Water Supply Management Area (DWSMA). According to WisDNR
Well Driller Viewer,45 groundwater protection features, including trout streams, surveyed streams, and special
casing areas are not located within the project area in Wisconsin.
3) Onsite or Adjacent Wells
Based on the MDH’s Minnesota Well Index and the WisDNR Wells map, there are three wells located within the
study area (see Table 4-8. Wells within the Project Area and Figure 4-6). If any unknown wells are encountered
within the study area, they would be sealed in accordance with MDH regulations or Wisconsin Administrative
Code NR 812.26.
Table 4-8. Wells within the Project Area
Index Status Well ID Well
Name Well Depth Date Drilled State
Active EL430 N/A 105 FT May 17, 1992 WI
Unknown 8FT823 Unknown Unknown Unknown WI
Unknown 8FU921 Unknown Unknown Unknown WI
42 Wisconsin Geological and Natural History Survey. Geoscience Wisconsin, Volume 6. Accessed in March 2024 and available at
https://wgnhs.wisc.edu/catalog/publication/000223/resource/gs06.
43 SEH. Environmental Review for Trunk Hwy 243. May 30, 2023. Accessed in March 2024.
44 Minnesota Department of Health. Source Water Protection Web Map Viewer. Accessed in February 2024 and available at
https://mdh.maps.arcgis.com/apps/View/index.html?appid=8b0db73d3c95452fb45231900e977be4
45 Wisconsin Department of Natural Resources. Well Driller Viewer. Accessed in February 2024 and available at
https://dnrmaps.wi.gov/H5/?viewer=Well_Driller_Viewer
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Figure 4-6. Wells within or near the Project Area
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4.1.12.2 Describe effects from project activities on water resources and measures to minimize or
mitigate the effects below.
Wastewater
For each of the following, describe the sources, quantities and composition of all sanitary, municipal/domestic
and industrial wastewater produced or treated at the site.
If the wastewater discharge is to a publicly owned treatment facility, identify any pretreatment measures and
the ability of the facility to handle the added water and waste loadings, including any effects on, or required
expansion of, municipal wastewater infrastructure.
Not applicable.
If the wastewater discharge is to a subsurface sewage treatment systems (SSTS), describe the system used, the
design flow, and suitability of site conditions for such a system. If septic systems are part of the project, describe
the availability of septage disposal options within the region to handle the ongoing amounts generated as a
result of the project. Consider the effects of current Minnesota climate trends and anticipated changes in rainfall
frequency, intensity and amount with this discussion.
Not applicable.
If the wastewater discharge is to surface water, identify the wastewater treatment methods and identify
discharge points and proposed effluent limitations to mitigate impacts. Discuss any effects to surface or
groundwater from wastewater discharges, taking into consideration how current Minnesota climate trends and
anticipated climate change in the general location of the project may influence the effects.
Not applicable.
Stormwater
Describe changes in surface hydrology resulting from change of land cover. Describe the routes and receiving
water bodies for runoff from the project site (major downstream water bodies as well as the immediate receiving
waters). Discuss environmental effects from stormwater discharges on receiving waters post construction
including how the project will affect runoff volume, discharge rate and change in pollutants. Consider the effects
of current Minnesota climate trends and anticipated changes in rainfall frequency, intensity and amount with this
discussion. For projects requiring NPDES/SDS Construction Stormwater permit coverage, state the total number
of acres that will be disturbed by the project and describe the stormwater pollution prevention plan (SWPPP),
including specific best management practices to address soil erosion and sedimentation during and after project
construction. Discuss permanent stormwater management plans, including methods of achieving volume
reduction to restore or maintain the natural hydrology of the site using green infrastructure practices or other
stormwater management practices. Identify any receiving waters that have construction-related water
impairments or are classified as special as defined in the Construction Stormwater permit. Describe additional
requirements for special and/or impaired waters.
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A drainage assessment was conducted for the Hwy 243 Osceola Bridge Project during project development in
2023 and 2024. The existing condition of stormwater management was assessed and a focus on enhancing
water quality was integrated into the design of the project. Local and regional government requirements
pertaining to stormwater management, including runoff rate and volume control and water quality rules were
also reviewed.
The existing Hwy 243 Bridge deck drainage system includes scuppers (openings that drain directly through the
bridge deck) that convey stormwater runoff and roadway contaminants (e.g., gasoline, oil, salt, sand, etc.) or
accidental spills of materials directly to the St. Croix River. Stormwater runoff from the Hwy 243 approach
roadways in Minnesota and Wisconsin are conveyed to receiving waters, through storm sewer, ditches, and
culverts. The receiving waters include wetland complexes that are backwaters of the St Croix River, Osceola
Creek (which drains to the St Croix River) and the St. Croix River directly. The St. Croix River exhibits outstanding
water quality and is identified as an “outstanding resources water” by Minnesota and Wisconsin. The water
quality of the St. Croix River also is an important criterion for its inclusion in the national wild and scenic river
system. Therefore, the goal of the drainage design for this project is to treat as much stormwater as possible
prior to discharging to the St. Croix River, while balancing aesthetics, wetland and tree impacts, right of way
considerations, maintenance, and cost.
The Construction NPDES permit requires permanent best management practices (BMPs) if the project creates 1
acre or more of increased impervious area. Although MnDOT Metro District also has a Municipal Separate Storm
Sewer System (MS4) permit, this project is outside of the Metro urbanized census area, therefore there are no
additional requirements from MS4 permit. New (increased) impervious area proposed with the project in
Minnesota will be approximately 0.6 acres, therefore, permanent stormwater BMPs are not required. Estimated
impervious surface changes are tabulated in Table 4-9. However, the project design includes the construction of
a wet pond just west of Osceola Landing and south of Hwy 243 to improve the water quality of the St. Croix
River and offset any impacts due to added impervious area. Nearly all of the stormwater runoff within the
project area within Minnesota and all of the runoff from the proposed bridge will drain to the wet pond for
treatment. The wet pond was determined to be the preferred treatment mechanism in this area because it
performs well for sediment and phosphorus removal and is less susceptible to sedimentation and damage from
flood events compared to other treatment mechanisms such as infiltration. In addition, wet ponds are
compatible with the soil and groundwater conditions within floodplains, while infiltration basins are difficult to
construct successfully due to concerns with both soil type and groundwater elevation. The proposed Minnesota
wet pond west of Osceola Landing is projected to remove 78% of Total Suspended Solids (TSS) from stormwater
runoff. TSS is a water quality parameter that is defined as the quantity of material suspended in a known volume
of water and is a common metric used to assess sediment removal.
Table 4-9. Estimated Impervious Surface Changes with the Project
State Proposed Disturbance
(acres)
Existing Impervious
(acres)
Proposed Impervious
(acres)
Net New Impervious
(acres)
MN 5.8 1.5 2.1 0.6
WI 2.7 1.2 1.7 0.5
Total 8.5 2.7 3.8 1.1
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New impervious area proposed with the project in Wisconsin will be approximately 0.5 acres, making the
combined increased new impervious 1.1 acres for the whole project. Wisconsin PDES permit does not require
permanent BMPs as the project meets the definition of minor reconstruction of a highway. During project
development, however, WisDNR staff requested that there be no net increase in TSS in the stormwater that
discharges to the St. Croix in Wisconsin, which is consistent with the goals of the project stormwater design to
treat as much stormwater as possible prior to discharge to the St. Croix River. The Wisconsin side of the project
area is characterized by bluffs and steep slopes; therefore, a pond or surface BMP is not feasible. Instead, storm
sewer will convey runoff from the roadway to a sump manhole just southwest of the WI river bridge abutment,
while the rock catchment ditch adjacent to the bluff south of Hwy 243 will convey runoff from the bluff area to a
small sediment trap adjacent to the sump manhole. In addition to the project area, these two stormwater
management features will provide treatment for a small offsite area. The proposed sump manhole is projected
to remove 17% of TSS draining to it, while the sediment trap is projected to remove 20% of TSS draining to it. A
maintenance plan for the proposed drainage features in Wisconsin will be developed by WisDOT.
For the entire project combined, the stormwater management features are projected to reduce TSS from
stormwater runoff by 57% from existing condition. These features and the benefits provided are depicted in
Figure A2 and Figure A3 in APPENDIX A (Figures).
Floodplains – Temporary Impacts
Several constructability methods to remove the existing bridge and replace it with the proposed bridge were
evaluated based on various models, as well as design and regulatory requirements. These requirements are
listed below. Additional details regarding temporary and permanent floodplain impacts can be found in
APPENDIX H (Floodplain Assessment).
Regulatory
• MnDNR recognizes a 0.5-foot allowable stage increase for the temporary condition in the 100-year
event for major river projects. This criterion assumes the additional stage will not impact insurable
structures.
• WisDNR does not recognize a 0.5-foot allowable stage increase for temporary causeways (Wisconsin
Administrative Rules NR116 and FEMA 44 CFR (various sections)). WisDNR reviews temporary floodplain
increases on a case-by-case basis for environmental impacts and regulatory floodplain requirements.
• Limit increases in velocities to less than 1 feet per second (fps) in the 2-year flood event from existing to
temporary conditions.
Design
• Top of causeway elevation – minimum 1 feet of freeboard (preference of 2-3 feet to maintain
constructability as much as possible) to maximize use during the construction months.
• Maintain a minimum 40-foot navigation opening for existing boat traffic, including the paddle-wheeler
storage upstream of the crossing.
• Assume all piers will be in the river (worst case condition).
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During the evaluation process, several causeway configurations were modeled to balance the opening span with
the top of causeway elevation. The general cross-section modeled is shown in Figure 4 of Temporary River
Impact Analysis Memorandum in APPENDIX H (Floodplain Assessment). Results of the analysis are found in
Table 4-10. Causeway Alternatives Analysis.
It was determined that a combination of causeways and barges are most suitable for:
• Navigation opening
• Culverts or other openings in the causeways for river flow, as well as aquatic organism passage
Table 4-10. Causeway Alternatives Analysis
Scenario
Causeway
Elevation
(ft)
100-year Stage
Increase
(ft)
Summer median
event freeboard
(ft)
2-year
Velocity Delta
(fps)
40 ft center 688.10 0.50 -3.97 0.10
76 ft center, set at 3ft above
existing summer median event 684.87 0.23 -3.30 0.10
76 ft center 689.60 0.50 0.23 0.10
40 ft center, 2-20 ft openings LT
& RT* 689.70 0.50 0.50 0.10
40 ft center, 2-30 ft openings LT
& RT* 690.70 0.50 3.56 0.10
76 ft center, 20 ft opening
LT 690.40 0.50 2.54 0.10
110 ft center 691.20 0.50 4.85 0.10
110 ft center, lowered to 1ft
freeboard 687.35 0.27 1.00 0.10
110 ft center, 2-10x10 RCB** 686.69 0.23 1.00 0.10
90 ft center 690.30 0.50 2.64 0.10
90 ft center, 2-10x10 RCB 690.70 0.50 3.69 0.10
*LT and RT indicate the left and right sides of the channel, respectively.
**RCB indicates reinforced concrete box culvert.
The causeway will be in-place for a period of two construction seasons. During this time, river flows will pass
through the center opening, effectively limiting movement of water directly upstream and downstream of the
causeways. Adding culverts in this area will allow fish passage and will provide some movement of water in
these ineffective flow areas.
In addition, Osceola Creek enters the St. Croix River directly upstream of the bridge. The causeway, and fingers
to build the piers, may slow creek water down and cause sediment deposits upstream of the causeway.
Installing a larger culvert in the east causeway will maintain some river flows and may reduce deposition of
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sediment. Additional culverts also provide some capacity across the causeway, allowing the top to be slightly
higher.
After a review of the various alternatives the following observations were made:
• The larger opening between the two sides of the river allows the causeway to be raised and reduces the
risk of overtopping.
• None of the alternatives increase the velocities from the existing conditions more than 0.1 foot per
second.
• Including smaller openings in each causeway allows for more height, slightly reducing risk of
overtopping.
The recommended causeway configuration includes the 90-foot center opening with smaller 10-foot-wide
openings in each causeway. The 90-foot opening maximizes the space between existing and proposed piers
while allowing a buffer for pier construction. This alternative also provides a preferential freeboard and meets
the 100-year allowable stage increase.
See the Temporary River Impact Analysis Memorandum in APPENDIX H (Floodplain Assessment).for additional
details.
Floodplains – Permanent Impacts
A transverse floodplain encroachment of approximately 600 feet is proposed with this project, see APPENDIX H
(Floodplain Assessment).There is no significant potential for interruption of a transportation facility which is
needed for emergency vehicles or provides a community’s only evacuation route. There is no significant impact
on natural and beneficial floodplain values, through the implementation of many mitigation measures for
fisheries, wetlands, plants, open space/aesthetics, public boat access and passage, channel changes, threatened
and endangered species, and water quality. These mitigation measures are being documented in APPENDIX F
(Environmental Management Plan).
The proposed bridge replacement will mimic the existing hydraulic conditions; therefore, no stage increase is
anticipated for permanent conditions after this project. No significant increased risk of flooding is anticipated.
Lastly, the project will not support and/or result in incompatible floodplain development. Based on all of the
above, no significant floodplain impacts are expected.
The proposed temporary and permanent impacts to the regulatory floodplain will be reviewed in conjunction
with the Village of Osceola (local zoning authority) in final design and permitting to ensure that the standards of
the local floodplain ordinance are followed and documented.
Avoidance, Minimization, and Mitigation Measures
Although there would be an increase of impervious surface within the project area, the proposed project would
improve the water quality of stormwater runoff through the implementation of a permanent stormwater
management system. The system would meet the standards of the MPCA and WisDNR and local MS4
requirements in Minnesota. The general objective of these obligations is to require that a volume of stormwater
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runoff is treated before discharge to other waters. Stormwater management features that are being designed
with the project were identified based on the following criteria:
• Located within existing ROW and MnDOT/WisDOT easements.
• Avoidance of existing pier locations.
• Prioritized reasonable outlet locations with the intent of minimizing the need for drainage structures
suspended from the bridge.
• Prioritized upland locations to minimize impacts to wetlands and aquatic resources.
A total of two locations and three stormwater management features would provide water quality treatment and
rate control. Locations and details of stormwater management areas are shown in Figure A2 and Figure A3 in
APPENDIX A (Figures). Overall, the project would provide enhanced treatment for the St. Croix River as
stormwater runoff is not currently being treated in the project area.
Construction associated with the proposed project would disturb existing paved and vegetated surfaces and
expose underlying soils to precipitation and runoff. Runoff from these disturbed soils could potentially travel
from the construction site and create sediment deposits in adjacent waterways and waterbodies. Additionally,
the potential exists for contamination found in exposed soil and other pollutants associated with construction
(e.g., concrete washout, fertilizer, vehicle fluids, etc.) to be exposed during construction. Without temporary
stormwater management (required by state and federal requirements), these activities could also result in an
increase in runoff volume and discharge rates from the construction site that could erode or weaken slopes and
transport additional sediment to receiving waters.
Temporary erosion and sediment control measures would be implemented throughout construction to mitigate
potential effects to water resources. An NPDES Construction Storm Water Permit in Minnesota and a WPDES
Transportation Construction General Permit in Wisconsin will be required for the proposed project and the
project will adhere to permit requirements. These permits require the procurement of a project SWPPP, which
includes instructions for both the construction stage pollution prevention measures and temporary and
permanent sediment and erosion control. All aspects of pollution prevention, sediment, and erosion control
measures would be in place and maintained throughout the entire construction period with an implementation
timeline as stated in the SWPPP. Sediment and erosion control would be managed through planting and the
placement of stabilizing perimetry control at all locations where surface stormwater leaves the construction site
including additional measures near areas of environmental sensitivity. Erosion control measures would not be
removed until all disturbed areas have been completely stabilized.
Floodplain modeling with the temporary causeways will be provided to MnDNR and WisDNR as part of final
design and permitting processes. MnDOT and WisDOT will identify any insurable structures that would be
impacted by temporary flood stage increases with the causeways based on final causeway elevations. WisDOT
will provide written notification to all landowners with insurable structures that would be impacted by the
increase caused by the temporary causeways during construction.
Only necessary construction equipment will be operated and stored in the floodway. Other construction
equipment will be stored in construction staging areas along the Hwy 243 approaches in Minnesota and
Wisconsin.
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The contractor will be required to develop an emergency action plan for response to potential flood events
during construction. The emergency action plan will identify St. Croix River flow velocity and elevation
thresholds and procedures for removal of construction equipment and materials from the riverway.
Climate Trends
Climates in the Midwest of the US are already changing rapidly and will continue to do so for the foreseeable
future.46 Though precipitation is predicted to increase in intensity and volume due to climate change, the project
is being designed using current standards. This current standard approach has been reviewed by MnDOT and
WisDOT. A standard practice and formal guidance on designing for climate trends has not yet been developed to
address intensifying precipitation. However, as discussed in Section 4.1.7, a “resiliency check” storm would be
modeled as the project develops to identify and minimize vulnerability and risks in the project area. The
resiliency check storm is currently defined as a 15 percent increase in the 100-year storm event, which is a
statewide temporary placeholder until more robust precipitation frequency estimates based on nonstationary
climate data are assessed and published.
Water appropriation
Describe if the project proposes to appropriate surface or groundwater (including dewatering). Describe the
source, quantity, duration, use and purpose of the water use and if a DNR water appropriation permit is
required. Describe any well abandonment. If connecting to an existing municipal water supply, identify the wells
to be used as a water source and any effects on, or required expansion of, municipal water infrastructure.
Discuss environmental effects from water appropriation, including an assessment of the water resources
available for appropriation. Discuss how the proposed water use is resilient in the event of changes in total
precipitation, large precipitation events, drought, increased temperatures, variable surface water flows and
elevations, and longer growing seasons. Identify any measures to avoid, minimize, or mitigate environmental
effects from the water appropriation. Describe contingency plans should the appropriation volume increase
beyond infrastructure capacity or water supply for the project diminish in quantity or quality, such as reuse of
water, connections with another water source, or emergency connections.
The nature and extent of dewatering activities for this project are not yet known, though some temporary
dewatering may reasonably be anticipated during construction of bridge piers, stormwater management
facilities, or other underground utility work. If dewatering efforts exceed the minimum guidelines for a MnDNR
Water Appropriations permit, MnDOT will coordinate with the MnDNR prior to construction. Any dewatering
required for this project will be temporary, and no adverse effects on the groundwater or surface water are
anticipated. Depending on the dewatering activity (i.e., volume and duration), it is recommended that the
project SWPPP include provisions for the management of the discharge to prevent erosion and particulate
pollutant loading in the receiving water.
46 Minnesota Department of Natural Resources (MnDNR). Climate trends. Accessed in June 2024 and available at
https://www.dnr.state.mn.us/climate/climate_change_info/climate-trends.html
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Best management dewatering practices would be identified in the SWPPP, and a project dewatering plan would
be attached to the construction documents. All locations that are determined to require dewatering would be
included in the dewatering plan.
Climate Resiliency During Construction
Dewatering activities for cofferdams during bridge construction could be affected by increased frequency of
intense storms. Large storm events could overtop cofferdams. Pumping and treatment systems managed under
normal weather conditions could be inundated by large storms and result in untreated discharge to surface
waters. MnDOT will require cofferdams to be constructed to a certain elevation based on hydraulic modeling to
minimize the risk of overtopping. Water pumped from the cofferdams would be treated prior to discharge as
identified in the SWPPP.
Surface Waters
Wetlands - Describe any anticipated physical effects or alterations to wetland features such as draining, filling,
permanent inundation, dredging and vegetative removal. Discuss direct and indirect environmental effects from
physical modification of wetlands, including the anticipated effects that any proposed wetland alterations may
have to the host watershed, taking into consideration how current Minnesota climate trends and anticipated
climate change in the general location of the project may influence the effects. Identify measures to avoid (e.g.,
available alternatives that were considered), minimize, or mitigate environmental effects to wetlands. Discuss
whether any required compensatory wetland mitigation for unavoidable wetland impacts will occur in the same
minor or major watershed and identify those probable locations.
Eight wetland basins of differing types would be impacted by the proposed project, totaling 0.35 acres of
permanent cut or fill impacts. All impacts to wetlands are assumed to be permanent at this time. The specific
nature of the proposed wetland impacts will be studied further as engineering progresses into final design.
Temporary impacts to wetlands will be determined during final design and permitting for the Hwy 243 Osceola
Bridge Project. Details regarding wetland impacts and their locations can be found in APPENDIX G (Wetland
Assessment & Two-Part Finding). Indirect effects to the host watershed may include altered hydrological
patterns and changes in vegetation within the project construction limits. Climate trends such as increased
precipitation and intensifying droughts could exacerbate the aforementioned effects. To minimize impacts to
the host watershed, standard best management practices (BMPs) would be used to prevent project site runoff
from entering adjacent wetland areas, and only clean fill would be placed in wetland areas to construct the
project. Native seed mixes would be utilized, as appropriate, to restore areas of temporary impact to pre-project
conditions.
Alternatives
The Alternatives Analysis process, which is detailed in APPENDIX C (Alternatives), evaluated the following
concepts:
• No Build Alternative
• Build Concept A – Rehabilitation
• Build Concept B – Existing Alignment
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• Build Concept C – North Alignment
• Build Concept D – South Alignment
• Build Concept E – 2nd Avenue Alignment
• Build Concept F – New Alignment
The proposed project considered a variety of different bridge alternatives designed to meet the project’s
primary need, bridge condition. Identified secondary needs include walkability/bikeability, with maintenance of
traffic during construction, Osceola Landing considerations, stormwater management, regulatory requirements,
and ecological connectivity identified as additional considerations. Three build alternatives were advanced for
further study in Step 3 of the alternative analysis process, including: Build Alternative B (existing alignment),
Build Alternative C (north alignment), and Build Alternative D (south alignment). Impacts to aquatic resources,
among other factors, were evaluated during this analysis. The Preferred Alternative, Build Alternative B (existing
alignment), results in the least amount of wetland impacts and was selected as the Preferred Alternative.
Minimization and Mitigation Measures
Wetlands and watercourses are afforded protection under the Clean Water Act (Section 404, Executive Order
11990 – Protection of Wetlands). The USACE regulates wetlands in both states. In Minnesota, the WCA regulates
wetlands. MnDOT is the authority administering WCA for wetlands located in MnDOT right of way and Chisago
County is the authority administering WCA for wetlands beyond MnDOT ROW. Wetlands and waterbodies
identified as MnDNR Public Waters are regulated by the MnDNR. The MPCA also regulates wetlands in
Minnesota through water quality requirements. In Wisconsin, the WisDNR regulates wetlands and
watercourses. Laws protecting wetlands and aquatic resources require projects to perform “sequencing” by
evaluating practicable methods of avoiding, minimizing, and lastly mitigating, through compensatory wetland
credit replacement, any impacts to aquatic resources.
It was not feasible to completely avoid all wetland impacts resulting from the proposed project. Wetland
impacts that are unavoidable have been minimized to the extent practicable without compromising safety. The
following design measures were used to minimize these impacts.
• Steeper inslopes (1:4 or steeper)
• Utilizing guardrail if necessary and meets design standards.
• Narrow shoulders (unless needed for bikes or pedestrians).
• Reduced design speed.
• Reconstruction along the existing bridge alignment.
• Urban section roadway (curb and gutter) along Minnesota and Wisconsin approach roadways.
Replacement of lost wetlands will be in accordance with Section 404 of the Clean Water Act, Executive Order
11990: Protection of Wetlands, and all state wetland protection regulations. The purpose of the wetland
compensatory mitigation plan will be to replace lost wetland functions and restore wetland area to fulfill the
regulatory mitigation requirements. Compensatory wetland replacement is planned at a minimum replacement
ratio of 2:1 for wetlands that are regulated by the Minnesota WCA. In Minnesota, compensatory mitigation
would be achieved through the withdrawal of wetland credits from an established MnDOT wetland bank in the
same wetland bank service area as the proposed permanent impacts, bank service area 6. In Wisconsin,
compensatory mitigation would be achieved through withdrawal of wetland credits from a WisDOT wetland
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bank at a minimum 1:1 replacement ratio in accordance with WisDNR and USACE requirements. The particular
banks used for impacts in each state will be decided during the permitting process.
Wetland vegetation would also be restored to preconstruction conditions as feasible using appropriate native
seed mixes. Wetland mitigation requirements would be further defined as detail design progresses and wetland
impacts are more accurately quantified and reported in the required wetland permit applications.
This project will require work in and adjacent to the St. Croix River, which is a National Wild and Scenic River.
This project will likely require a USACE Section 404 Individual Permit, as the Transportation Regional General
Permit generally does not authorize regulated activities which may affect or are located in a designated portions
of the National Wild and Scenic River System unless the appropriate Federal agency with direct management
responsibility for the river, has determined in writing that the proposed activity will not adversely affect the Wild
and Scenic River designation.
Other Surface Waters - Describe any anticipated physical effects or alterations to surface water features (lakes,
streams, ponds, intermittent channels, county/judicial ditches) such as draining, filling, permanent inundation,
dredging, diking, stream diversion, impoundment, aquatic plant removal and riparian alteration. Discuss direct
and indirect environmental effects from physical modification of water features, taking into consideration how
current Minnesota climate trends and anticipated climate change in the general location of the project may
influence the effects. Identify measures to avoid, minimize, or mitigate environmental effects to surface water
features, including in-water Best Management Practices that are proposed to avoid or minimize
turbidity/sedimentation while physically altering the water features. Discuss how the project will change the
number or type of watercraft on any water body, including current and projected watercraft usage.
Removal of the existing bridge and reconstruction of the new Hwy 243 Bridge over the St. Croix River is
challenging given the physical terrain and relatively shallow depth of water in the river. Review of construction
methods has been completed and identified the need for temporary causeways to be constructed from both
sides for up to two construction seasons. Several causeway configurations have been explored to meet the
construction needs while meeting regulatory requirements for flooding, boat access, and channel velocities. The
final configuration is likely to include a large opening for the navigation channel to allow passage of boats along
with minor openings in the causeway to balance the flood levels, velocities, and access.
Channel impacts are also expected within the St. Croix River and Osceola Creek as part of this project. New fill,
totaling 0.88 acres, would be placed in the river for the replacement bridge piers and the temporary earthen
causeways required for construction of the new bridge. The expected duration of in-water construction is
approximately 24 months. During construction, the existing bridge piers would be removed, and river bottom
habitat would be restored in these locations once construction is complete.
The confluence of Osceola Creek with the St. Croix River is on the north side of the Hwy 243 Bridge. An earthen
causeway would be constructed at Osceola Creek along the Wisconsin shoreline to allow for removal of the
existing bridge and construction of the new bridge. A new bridge pier would be constructed adjacent to the
Osceola Creek confluence along the Wisconsin shoreline. The outlet of Osceola Creek would be re-aligned to the
north, and the north side of this pier would be armored with rip-rap material to prevent erosion and scouring at
the pier as Osceola Creek discharges to the St. Croix River. The new outlet of Osceola Creek will be designed to
match existing dimensions, slope, and velocities. A staging plan will be developed in final design for construction
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of the outlet, including methods for maintaining Osceola Creek flow during construction with the temporary
causeways and construction of the new outlet. Erosion control best practices will be used along the Wisconsin
shoreline to control sediment discharge to the St. Croix River. The temporary impacts to Osceola Creek at the
confluence with the St. Croix River and final design of the new outlet will be approved by WisDNR as part of the
WisDOT/WisDNR Cooperative Agreement process.
Avoidance, Minimization, and Mitigation Measures
Causeways would be used in order to meet all the necessary requirements of working within the St. Croix River.
Barges and cofferdams would also be used, in order to minimize construction impacts in the river. After
construction is complete, the temporary fill for the causeways would be removed to restore preconstruction
contours and preconstruction soil conditions, which includes the alleviation of any soil compaction that is caused
by construction and river bottom restoration.
Construction of temporary causeways, as discussed in Section 4.1.6, is proposed on the west and east sides of
the bridge on the Minnesota and Wisconsin approaches which would extend into the navigation channel. Piers
would be removed down to the base such that navigation is not impaired. The shoreline would be stabilized and
restored prior to the completion of construction. In-water pollution prevention measures would be established,
documented, and followed as part of the project SWPPP.
The cofferdams would be removed when the pier structures have been constructed. Water pumped out of
cofferdams could contain high concentrations of suspended solids. Adequate sediment control and treatment of
water affected by construction activity would be completed before the pumped water is released. This includes
filtered sump pits or other appropriate dewatering systems. Dewatering systems must be inspected frequently
and repaired or replaced if sediment buildup recurs or if the system does not function as designed. The
accumulated sediment that is removed from a dewatering mechanism must be spread onsite and stabilized,
used as fill, or disposed of at an approved disposal site. Dewatering discharge may be pumped directly to a
settling basin or other treatment pond.
Recurring examinations of erosion control practices will be required. Appropriate in-water pollution prevention
measures like flotation silt curtains would be utilized to contain the active construction area within the river. The
SWPPP will provide further details on best management practices to alleviate turbidity and sedimentation in the
waterway.
Temporary and permanent impacts within the St. Croix River would be under the jurisdiction of the MnDNR or
the WisDNR, and USACE. Permanent impacts that result from pier construction may be mitigated, in part, by the
removal of the existing piers. Aquatic resource mitigation requirements would be further defined as final design
progresses and impacts can be more accurately quantified and disclosed in the required aquatic resource permit
applications. Permitting authorization for the Hwy 243 Osceola Bridge Project is subject to an affirmative Section
7(a) evaluation and determination from NPS.
Prior to construction, a detailed survey would be conducted to confirm the existing topography within wetlands
and watercourses. When construction is completed, the temporary fill for the causeways would be removed to
pre-construction contours as much as practicable. Vegetation within the wetlands would also be restored to
preconstruction conditions as feasible using appropriate native seed mixes.
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4.1.13 Contamination/Hazardous Materials and Wastes
4.1.13.1 Pre-project site conditions
Describe existing contamination or potential environmental hazards on or in close proximity to the project site
such as soil or ground water contamination, abandoned dumps, closed landfills, existing or abandoned storage
tanks, and hazardous liquid or gas pipelines. Discuss any potential environmental effects from pre-project site
conditions that would be caused or exacerbated by project construction and operation. Identify measures to
avoid, minimize or mitigate adverse effects from existing contamination or potential environmental hazards.
Include development of a Contingency Plan or Response Action Plan.
Early coordination between MnDOT and WisDOT began in 2017 and continued through 2020. Following early
coordination, an environmental review of corridor contamination risks was completed by SEH Inc. in Spring 2023
to summarize the existing and potential footprint of contaminated materials within approximately 500 feet of
the project area (Hwy 243 between MN-95 and WIS-35). All properties, public ROW areas, and intervening
waterways within 500 feet of the project area were evaluated and ranked according to perceived risk of
encountering contaminated materials from current and/or former land-uses and the potential presence of
contamination. The SEH Environmental Review Report and other related documentation (e.g., Phase I and Phase
II Environmental Site Assessment (ESAs)) will be available upon request from the MnDOT Project Manager.
The western portion of the project corridor in Franconia Township, Minnesota, west of the St. Croix River, has
been primarily occupied by agricultural or forestland with farmsteads and private residences. By the early 1950s,
an aggregate sand and gravel surface mine was located approximately one quarter mile northwest of the project
corridor. The mine has expanded in subsequent decades.
The eastern portion of the project corridor in Osceola, Wisconsin, east of the St. Croix River, has been developed
with industrial, commercial, and residential properties since at least the mid-1800s. A railroad corridor bisects
the eastern portion of the corridor. Industrial properties historically surrounded the railroad corridor, including
lumber and flour mills, bulk oil facilities, grain elevators, and produce and livestock product warehouses.
Downtown Osceola has been developed with commercial stores and restaurants. A hospital/clinic was
constructed in downtown Osceola in the approximate early 1970s.
From the Spring 2023 Environmental review of corridor contamination risks, a total of 25 sites of potential
environmental concern were identified in the land-based area of interest and four sediment sampling sites were
identified in the St. Croix River. The risk ranking system for the land-based areas in Minnesota and Wisconsin
generally involved assigning an initial baseline ranking of “high,” “medium,” or “low” risk and are described
further below.
Land-Based Risk Evaluations
The land-based rankings were determined based on current and/or former land-use factors and the potential
presence of environmental impairments. In both Minnesota and Wisconsin, known remediation sites with
ongoing investigations are considered “active” or otherwise considered “closed” by a governing regulatory
agency. In Minnesota, contamination may remain on a “closed” site but the “closed” designation signifies no
need for further cleanup actions. In Wisconsin, sites may be “closed” or “closed with continuing obligations”
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where disturbances of remaining contaminated soil or dewatering of impacted groundwater may require
additional remediation. The land-based risk ranking assignments are as follows:
• High risk: In general, sites with high environmental risk are properties that have documented releases of
chemicals or hazardous or regulated substances (e.g., active and inactive state and federal cleanup sites,
active and inactive dump sites, and active leaking underground storage tank sites), historical evidence of
industrial or commercial land use that could result in undetected contamination, or storage of large
volumes of petroleum or other chemicals (e.g., bulk storage tank facilities).
• Medium risk: Sites of medium environmental risk are properties associated with historical or current
land use that is perceived to carry a lower threat to public health or the environment. Medium risk sites
may share some characteristics of high-risk sites but the known or potential magnitude of chemical or
petroleum releases are generally less significant. Medium risk sites are generally regulated under State
or local government jurisdictions and not at the Federal level. Closed sites, such as closed leaking
underground storage tank sites, are considered medium risks because residual soil or groundwater
contamination may remain after initial investigations or remediation of the sites.
• Low risk: Low environmental risk sites include properties where minor volumes of chemicals or
hazardous materials have been used or stored (e.g., hazardous waste generators, and possibly some
farmsteads and residences).
The location of identified high, medium, and low risk sites are tabulated and illustrated in APPENDIX I
(Contaminated Properties).
St. Croix River Sediment Investigation
During the Summer of 2023, sediment screening and sampling were added to the geotechnical drilling in the St.
Croix River to evaluate dredging and disposal requirements. MnDOT will hire an environmental consultant in to
support additional investigations and construction monitoring.
The sediment investigation consisted of analysis of sediments obtained from four of the six geotechnical soil
borings (see APPENDIX I (Contaminated Properties) for more on locations and boring depth). Sediments were
sampled following MPCA guidance. Sediment was analyzed for grain size and hydrometer analysis, polycyclic
aromatic hydrocarbons, polychlorinated biphenyls, oil and grease, metals, phosphorous, nitrogen, and organic
carbon. Analysis found that there were no field indicators of contamination in sediment; however, arsenic was
detected in two sediment samples above the MPCA commercial/industrial soil reference value and a nitrogen
compound was detected above the Minnesota Department of Agriculture cleanup goal.
Impact Evaluation
No Build Alternative
Under the No Build Alternative, the Hwy 243 Osceola Bridge Project would not be constructed. Since the project
would not be constructed, there would be no temporary construction-related impacts to identified
contaminated properties.
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Preferred Alternative
The Preferred Alternative is anticipated to impact at least one land-based contaminated property with a high-
high or high-unknown ranking, which indicates a high probability for petroleum and non-petroleum-based
contaminated properties to have an impact on future ROW acquisition and construction activities. Construction
of the Preferred Alternative may also present risk of encountering unknown contamination.
Avoidance, Minimization, and/or Mitigation Measures
To understand more about the contaminated property risks to the project, a Phase II ESA investigation is
planned. The purpose of the Phase II ESA is to verify the presence of contamination and to conduct an initial
characterization of the extent and magnitude of contamination within MnDOT and WisDOT ROW areas. The
Phase II ESA also identifies any restrictions in potential soil reuse, based on MPCA and WisDNR guidance. If
contaminated materials are identified, a plan would be developed to properly handle and treat any
contaminated materials encountered during project construction in accordance with applicable state and
federal regulations. It is not anticipated that liability protections are needed as MnDOT will not acquire
additional ROW and WisDOT will acquire any property they need on the Eastern half of the project.
Correspondence related to contamination investigations is located in APPENDIX J (Agency Correspondence).
Drilling work plans would be completed for investigations of the soil and groundwater to establish the presence
of and the magnitude of chemical impacts to the environment. This information will be used in conjunction with
the construction design plans to write specific contract special provisions and a contaminated materials
management plan for handling known contaminated soils, dredged sediments, and groundwater that would be
encountered during construction.
Unknown materials may also be encountered during construction that were not identified during the initial site
investigations. A Construction Contingency Plan would be written and incorporated within the contaminated
material management plan, and would discuss how to handle unknown conditions that are encountered.
MnDOT will hire an environmental construction oversight contractor to help manage contaminated and
regulated materials in both Minnesota and Wisconsin to make sure that these materials are handled in
accordance with all appropriate federal, state, and local regulations.
4.1.13.2 Project related generation/storage of solid wastes
Describe solid wastes generated/stored during construction and/or operation of the project. Indicate method of
disposal. Discuss potential environmental effects from solid waste handling, storage and disposal. Identify
measures to avoid, minimize or mitigate adverse effects from the generation/storage of solid waste including
source reduction and recycling.
All solid wastes, soils, and sediments generated by construction of the proposed project would be disposed of
properly in a permitted, licensed solid waste facility. Solid wastes that require temporary stockpiling would be
covered or managed in a way that prevents any release to the environment. Project demolition of concrete,
steel, asphalt, and other potentially recyclable construction materials would be directed to the appropriate
storage, crushing, or renovation facility for recycling.
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4.1.13.3 Project related use/storage of hazardous materials
Describe chemicals/hazardous materials used/stored during construction and/or operation of the project
including method of storage. Indicate the number, location and size of any new above or below ground tanks to
store petroleum or other materials. Indicate the number, location, size and age of existing tanks on the property
that the project will use. Discuss potential environmental effects from accidental spill or release of hazardous
materials. Identify measures to avoid, minimize or mitigate adverse effects from the use/storage of
chemicals/hazardous materials including source reduction and recycling. Include development of a spill
prevention plan.
No above ground or below ground storage tanks are planned for permanent use in conjunction with this project.
Temporary storage tanks for petroleum products may be located in the project area for refueling construction
equipment during construction. Other chemicals used during construction would be stored as required by
respective state law in which the storage takes place.
Appropriate measures would be taken during construction to avoid spills that could contaminate soil,
groundwater or surface water in the project area. If a spill of hazardous or toxic substances should occur in
Minnesota during or after construction of the proposed project, it is the responsibility of the contractor (during
construction) or transport company to notify the Minnesota Department of Public Safety, Division of Emergency
Services, to report corrective actions. Any contaminated spills or leaks that occur during construction in
Minnesota are the responsibility of the contractor, who would immediately implement containment procedures,
notify the Minnesota Duty Officer, and work with the MPCA to contain and remediate contaminated
soil/materials in accordance with state and federal standards. In Wisconsin, any contaminant spills or leaks that
occur during construction are the responsibility of the contractor, who would immediately implement
containment procedures and notify WisDNR through the spill reporting hotline. They shall also notify the
WisDOT Environmental Coordinator and work with WisDNR to contain and remediate any contaminated
soil/materials in accordance with state and federal standards.
Spills that occur on the highway and the Hwy 243 Bridge after construction will be managed following MnDOT’s
spill cleanup permit special provisions (e.g., MnDOT Spills Cleanup Standard Conditions and MnDOT Standard
Spills Procedure. Information regarding spill cleanup is on the MnDOT webpage at
https://www.dot.state.mn.us/environment/contaminatedmaterials/spills.html.
4.1.13.4 Project related generation/storage of hazardous wastes
Describe hazardous wastes generated/stored during construction and/or operation of the project. Indicate
method of disposal. Discuss potential environmental effects from hazardous waste handling, storage, and
disposal. Identify measures to avoid, minimize or mitigate adverse effects from the generation/storage of
hazardous waste including source reduction and recycling.
Removal of the existing bridge and associated structures within the site is not anticipated to generate new
hazardous waste. Toxic or hazardous waste to be stored within the site during construction would include the oil
necessary to operate heavy construction equipment, and during operations may include commercial cleaning
supplies. Regulated materials that may require special handling include treated wood, potential asbestos
culverts, traffic signals/lighting, potential lead paint, lead plates, and electronics. Regulated materials/wastes
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would be managed on this project in accordance with MnDOT and WisDOT special provisions. Areas of
hazardous waste contaminated soil would be excavated and managed by appropriately trained contractors. Any
hazardous wastes generated from the project would be managed through each state’s representative hazardous
and universal waste disposal contract.
4.1.14 Fish, Wildlife, Plant Communities, and Sensitive Ecological Resources (Rare Features)
4.1.14.1 Describe fish and wildlife resources as well as habitats and vegetation on or in near the site.
The project area is within the St. Croix Moraine ecological subsection as defined by the MnDNR Ecological
Classification System Field Guide. The project area is also within the WisDNR’s Western Plains Ecological
Landscape and the MnDNR’s St. Croix Outwash Plain and Stagnation Plains Ecoregion. The project area within
Minnesota is adjacent to multiple MnDNR Native Plant Communities with outstanding biodiversity. Near the
western limit of the project, north and south of Hwy 243, there are Mesic Hardwood Forest Systems that
contain red oak (Quercus rubra), sugar maple (Acer saccharum), Basswood (Tilia americana), and bitternut
hickory (Carya cordiformis). North of Osceola Landing, across from Hwy 243, is a Floodplain Forest System with
silver maple (Acer saccharinum) and Virginia creeper (Parthenocissus quinquefolia).
The Hwy 243 Bridge spans over the St. Croix River, a Wild and Scenic River which flows between Minnesota and
Wisconsin. It provides ecological value that is unique to the region and is considered an Outstanding Resource
Water by both Minnesota, Wisconsin, and the National Park Service. It is comprised of shallow, warm water fish
habitats which supports a diverse fishery. Osceola (also known as Cascade) Creek drains to the St. Croix River
from Wisconsin and is a cool/cold water resource that supports both a warm water and cold water fish habitat.
Fish and Wildlife Species
The warm water fishery within the St. Croix River includes more than 60 fish species that includes the
recreationally important walleye (Sander vitreus), sauger (Sander canadense), northern pike (Esox lucius),
muskellunge (Esox masquinongy), smallmouth bass (Micropterus dolomieu), largemouth bass (Micropterus
salmoides), white bass (Morone chrysops), bluegill (Lepomis macrochirus), black crappie (Pomoxis
nigromaculatus), channel catfish (Ictalurus punctatus), and flathead catfish (Pylodictis olivaris). Additionally,
various state listed species are present in the St. Croix River, including the crystal darter (Crystallaria asprella),
black buffalo (Ictiobus niger), blue sucker (Cycleptus elongatus), river redhorse (Moxostoma carinatum),
pugnose shiner (Notropis anogenus), paddlefish (Polyodon spathula), and shoal chub (Macrhybopsis hyostoma).
These recreationally important and rare species, and numerous others (e.g., various redhorse species,
freshwater drum (Aplodinotus grunniens), etc.), can be presumed to occur within the project area.
Fish that are classified as aquatic invasive species are also found in this stretch of the St. Croix River. These
include grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix), and bighead carp
(Hypopthalmichthys nobilis).47 Additionally, invasive carp have been identified by the USCG in the St. Croix River
47 National Park Service. NPSpecies (Information on Species in National Parks). Accessed in March 2024 and available at
https://irma.nps.gov/NPSpecies/Search/SpeciesList/SACN.
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south of Taylors Falls. The USCG have also found zebra mussels (Dreissena polymorpha) and Eurasian milfoil
(Myriophyllum spicatum) downstream of the project study area in Lake St. Croix.
Non-fish aquatic species are also present within the St. Croix River, including aquatic macroinvertebrates and
freshwater mussels. Data and guidance from the USFWS, MnDNR, WisDNR, MnDOT, and WisDOT regarding the
project indicates there are populations of state and federally endangered/threatened species of mussels in the
project area. Mussel surveys were required prior to the construction of the project and were completed in 2020
and 2023. Federally listed and proposed species collected during these surveys include snuffbox (Epioblasma
triquetra), spectaclecase (Cumberlandia monodonta), and salamander mussel (Simpsonaias ambigua). State
(Minnesota and Wisconsin) listed species collected included mucket (Actinonaias ligamentina), purple wartyback
(Cyclonaias tuberculata), pistolgrip (Tritogonia verrcuosa), butterfly (Ellipsaria lineolata), spike (Eurynia dilatata),
monkeyface (Theliderma metanevra), among other non-listed species.
A relocation of freshwater mussels from the in-stream work area will occur prior to the start of project
construction. Further detailed results of the completed surveys are detailed in the next section of this EAW
question (4.1.14.2 Rare Features) and in APPENDIX K (Biological Assessment).
Mammalian species are abundant in or near the project area, due to the high-quality habitats that the St. Croix
National Scenic Riverway provides. Among those species include but are not limited to the white-tailed deer
(Odocoileus virginianus), eurasian elk (Alces alces), coyotes (Canis latrans), the common gray fox (Urocyon
cinereoargenteus) and red fox (Vulpes vulpes), black bears (Ursus americanus), and the federally threatened
(MN)/endangered (WI) gray wolf (Canis lupus).42 Bats also reside in the project area, which are described in the
following section (4.1.14.2 Rare Features).
The St. Croix National Scenic Riverway provides habitat for numerous bird species, including the golden winged
warbler (Vermivora chrysoptera) (under Federal review) and whooping crane (Grus americana) (experimental
non-essential population).
Amphibian and reptilian species are also abundant in or near the project area. These include several species of
frogs and salamanders, as well as snakes and turtles.42 The project area contains the Minnesota and Wisconsin
state-listed wood turtle (Glyptemys insculpta) (threatened) and the Minnesota state-listed and Wisconsin special
concern Blanding’s turtle (Emydoidea blandingii) (threatened), which are detailed further in the following
sections.
The project area is also known to harbor two rare insect species; the federally-endangered rusty-patched
bumble bee (Bombus affinis) and the candidate monarch butterfly (Danaus plexippus). As the monarch is known
to occur in the project area, and the project is within a rusty-patched bumblebee High Potential Zone (HPZ),
both species are assumed present in the project area.
Wildlife Management Areas
No Wildlife Management Areas are directly adjacent to or within the project area.
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Migratory Birds and Bald Eagles
A review for migratory birds was completed to address migratory and non-migratory bird use of the bridge
structure as well as the surrounding habitats. Bird use is defined as actual use of the structural components of
the bridge for perching, roosting, nesting, hovering, and other behaviors. Protected bird species nests (likely
from American robins (Turdus migratorius)) were present on the Hwy 243 Bridge during a 2023 inspection.
MnDOT OES completed a bald eagle (Haliaeetus leucocephalus) nest survey of the project study area in
December 2021. No bald eagle nests were observed within the vicinity of the project. A bald eagle nest is on the
north side of Hwy 243 in Minnesota; however, this nest is estimated to be more than 1,000 feet from the
highway. An additional bald eagle survey is planned prior to construction of this project.
4.1.14.2 Rare Features
Describe rare features such as state-listed (endangered, threatened or special concern) species, native plant
communities, Minnesota Biological Survey Sites of Biodiversity Significance, and other sensitive ecological
resources on or within close proximity to the site. Provide the license agreement number (LA- ) and/or
correspondence number (MCE ) from which the data were obtained and attach the Natural Heritage Review
letter from the DNR. Indicate if any additional habitat or species survey work has been conducted within the site
and describe the results.
Federally Listed Species
A list of federally threatened, endangered, proposed and candidate species, and designated and proposed
critical habitat that overlaps with the action area, was requested via the USFWS Information for Planning and
Consultation (IPaC) web application. Based on this list, the project is within the range of the following species:
• Gray wolf (Canis lupus) – Federally Threatened in Minnesota, Federally Endangered in Wisconsin -
habitat found in northern forests.
• Tricolored bat (TCB) (Perimyotis subflavus) – Proposed Federally Endangered - known to hibernate in
caves, mines, and tunnels. Roosts in live or dead trees, buildings, culverts, and bridges. Forages along
forested edges over waterways.
• Northern long-eared bat (NLEB) (Myotis septentrionalis) – Federally Endangered – known to hibernate in
caves, mines, and tunnels. Roosts in live or dead trees, buildings, and occasionally on bridges or culverts.
Forages along forested edges over waterways. According to the Minnesota Department of Natural
Resources Natural Heritage Information System and information provided by the Wisconsin Department
of Natural Resources, there are two hibernacula with documented NLEB and TCB use within 5 miles of
the project area, including one within the project’s action area.
• Whooping crane (Grus americana) – Non-essential Experimental Population - utilizes a variety of
habitats, including coastal marshes and estuaries, inland marshes, lakes, open ponds, shallow bays, salt
marsh and sand or tidal flats, upland swales, wet meadows and rivers, pastures, and agricultural fields.
• Higgins eye pearlymussel (Lampsilis higginsii) – Federally Endangered - habitats in the Mississippi and St.
Croix Rivers.
• Snuffbox (Epioblasma triquetra) – Federally Endangered - habitats in the Mississippi and St. Croix Rivers.
• Spectaclecase (Cumberlandia monodonta) – Federally Endangered - habitats in the Mississippi and St.
Croix Rivers.
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• Winged mapleleaf (Quadrula fragosa) - Federally Endangered - habitats in the Mississippi and St. Croix
Rivers.
• Salamander mussel (Simpsonaias ambigua) – Proposed Federally Endangered and proposed Critical
Habitat – habitats in the Mississippi and St. Croix Rivers.
• Rusty patched bumble bee (RPBB) (Bombus affinis) – Federally Endangered – habitats found in
grasslands with flowering plants from April through October, underground and abandoned rodent
cavities or clumps of grasses above ground as nesting sites, and undisturbed soil for hibernating queens
to overwinter. Due to the presence of known RPBB populations near the project area and the project
area being partially within a mapped High Potential Zone for the species, RPBB presence is assumed
present in the project area. A RPBB habitat assessment was conducted by MnDOT ecologists, which can
be found in APPENDIX K (Biological Assessment).
• Monarch butterfly (Danaus plexippus) – Candidate Species – found in grassland habitats where
milkweed (Asclepias spp.) and flowers are present.
The reach of the St. Croix River within the project are under review by the USFWS to be designated as Critical
Habitat for the snuffbox mussel (Epioblasma triquetra), spectaclecase mussel (Cumberlandia monodonta), and
the salamander mussel (Simpsonaias ambigua).
Wisconsin Listed Species & Wisconsin Endangered Resources Review
A Wisconsin Endangered Resources Review (ERR) request was submitted to identify known occurrences of rare
plant and animal species in and around the project area in Wisconsin. The Wisconsin ERR identified twenty (20)
known occurrences of rare species within or adjacent to the study area. See APPENDIX J (Agency
Correspondence) for the WisDNR Initial Response Letter.
These included the state-threatened river redhorse (Moxostoma carinatum), the state-endangered crystal
darter (Crystallaria asprella), the state-threatened black buffalo (Ictiobus niger), the state-threatened blue
sucker (Cycleptus elongatus), the state-threatened shoal chub (Macrhybopsis hyostoma), the state-threatened
northern long-eared bat (Myotis septentrionalis), the state-threatened big brown bat (BBB) (Eptesicus fuscus),
the state-threatened tricolored bat (Perimyotis subflavus), and the state-threatened little brown bat (LBB)
(Myotis lucifugus).
Eleven of the rare species were species of mussels. These included the state-endangered elephant ear (Elliptio
crassidens), The state-endangered spectaclecase (Cumberlandia monodonta), the state-endangered snuffbox
(Epioblasma triquetra), the state-threatened wartyback (Quadrula nodulata), the state-threatened fawnsfoot
(Truncilla donaciformis), the state-threatened monkeyface (Theliderma metanevra), the state-endangered
butterfly (Ellipsaria lineolata), the state-endangered winged mapleleaf (Quadrula fragosa), the state threatened
buckhorn (Tritogonia verrucosa), the state-endangered Higgins eye (Lampsilis higginsii), and the state-
threatened wood turtle (Glyptemys insculpta).
Several Wisconsin state species of special concern were also identified in the ERR as occurring within or near the
project area. These include lake sturgeon (Acipenser fulvescens), American eel (Anguilla rostrata), elktoe
(Alasmidonta marginata), the bat hibernaculum (special concern) which is near the project area, and the
Blanding's turtle (Emydoidea blandingii).
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Minnesota Listed Species
The Minnesota Natural Heritage Information System (NHIS) database was queried by MnDOT to identify
element occurrences of any rare plant or animal species, native plant communities, or other significant natural
features within a 1-mile buffer of the project area in Minnesota. MnDOT has a liaison with the DNR who
performs reviews internally; therefore, there is no applicable License Agreement (LA) or Ecosystems Research
and Development Bureau (ERDB) number. The letter is included in APPENDIX J (Agency Correspondence).
Minnesota Species of Special Concern that reside in the project area include the tri-colored bat (Perimyotis
subflavus), big brown bat (Eptesicus fuscus), and little brown bat (Myotis lucifugus). These bats tend to hibernate
in caves, mines, and tunnels during the winter, and roost in trees and bridges structures near water sources
when not in hibernation.
Occurrences of Minnesota-listed fish species are known to occur within the St. Croix River including the state-
special concern lake sturgeon (Acipenser fulvescens), the state-special concern gilt darter (Etheostoma
microperca), and the state-special concern American eel (Anguilla rostrata).
Minnesota state-listed threatened species include the wood turtle (Glyptemys insculpta) and the Blanding’s
turtle (Emydoidea blandingii), as well as the plains spotted skunk (Spilogale interrupta) and the Eastern spotted
skunk (Spilogale putorius). The wood turtle is largely aquatic and prefers small to medium sized rivers and
streams with adjacent coniferous and deciduous forests.48 Typical Blanding’s turtle habitat includes wetland
complexes and nearby sandy uplands, as well as calm and shallow waters associated with rivers and streams
that are home to rich aquatic vegetation.49 Striped skunks live and thrive in rural and urban environments
throughout Minnesota. Eastern spotted skunks are generally found in open lands that have riparian woodlands,
shelterbelts, thickets, and brush. In agricultural areas they prefer cover made by humans, including outbuildings,
corncribs, trash piles, rock piles and haystacks.50
Minnesota threatened plant species include bog bluegrass (Poa paludigena), which is a native, cool-season grass
that typically thrives in wet, shady places such as swamps, bogs, and forested seeps.
The only fish species that is state-listed in Minnesota as endangered and occurs within the project area is the
crystal darter (Crystallaria asprella). This species prefers in medium to large rivers, typically with clean sand and
gravel river bottoms and moderate to fast currents.51
Minnesota state-listed fish species that are listed as threatened and occur within the project are the black
buffalo (Ictiobus niger), pugnose shiner (Notropis anogenus), and paddlefish (Polyodon spathula).
48 MnDNR. Rare Species Guide. Accessed in March 2024 and available at
https://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=ARAAD02020
49 MnDNR. Rare Species Guide. Accessed in March 2024 and available at
https://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=ARAAD04010
50 MnDNR. Living with skunks. Accessed in March 2024 and available at https://www.dnr.state.mn.us/livingwith_wildlife/skunk.html
51 MnDNR. Rare Species Guide. Accessed in March 2024 and available at
https://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=AFCQC01010
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Minnesota state-listed threatened species include mucket (Lampsilis abrupta), spike (Elliptio dilatate),
monkeyface (Quadrula sparsa), elktoe (Alasmidonta marginata), wartyback (Plethobasus cicatricosus),
fawnsfoot (Truncilla donaciformis), butterfly mussel (Ellipsaria lineolata), and fluted-shell (Lasmigona costata).
Mussel species that are state-listed as endangered are Higgins eye pearlymussel (Lampsilis higginsii), snuffbox
(Epioblasma triquetra), spectaclecase (Cumberlandia monodonta), winged mapleleaf (Quadrula fragosa),
salamander mussel (Simpsonaias ambigua), pistolgrip/buckhorn (Tritogonia verrucosa), elephant ear (Elliptio
crassidens), and purple wartyback (Cyclonaias tuberculata). These mussels generally occur in medium to large
rivers, which contain rock, gravel, and sand, along with a swift current, making the St. Croix River an optimal
habitat for freshwater mussels.
Mussel surveys were conducted in 2020 and 2023 for the St. Croix River within the project area. Five-hundred
and twenty-one (521) live individuals of 23 species were collected during the 2023 survey effort for this project.
The following federal and state-listed species were either collected during this survey or their presence is
assumed likely based on the findings of past surveys within 1.0 mile of the project area in 2018 and 2020:
• Butterfly (Ellipsaria lineolata)
• Elktoe (Alasmidonta marginata)
• Fawnsfoot (Truncilla donaciformis)
• Fluted-shell (Lasmigona costata)
• Higgins eye pearlymussel (Lampsilis higginsii)
• Mucket (Lampsilis abrupta)
• Purple wartyback (Cyclonaias tuberculata)
• Salamander mussel (Simpsonaias ambigua)
• Snuffbox (Epioblasma triquetra)
• Spectaclecase (Cumberlandia monodonta)
• Spike (Elliptio dilatate)
• Winged mapleleaf (Quadrula fragosa)
Minnesota Biological Survey - Sites of Biodiversity Significance
Natural prairie remnants (railroad prairies) and rare/endangered plant species have not been identified within
MnDOT right of way at locations where potential work is proposed. However, within and adjacent to the areas
of proposed work, the general areas on both the north and south sides of Hwy 243 are not only classified as
native plants communities of various types (Southern Mesic Oak Basswood Forest, Southern Floodplain Forest,
Northern Bulrush-Spikerush Marsh), but they are also classified as sites of outstanding biodiversity significance
as determined by the Minnesota Biological Survey. Outstanding sites contain the best occurrences of the rarest
species, the most outstanding examples of the rarest native plant communities, and/or the largest, most
ecologically intact or functional landscapes. The Sites of Biodiversity Significance adjacent to the project area are
ranked as such for it’s outstanding vegetative composition.
4.1.14.3 Impact Evaluation
Discuss how the identified fish, wildlife, plant communities, rare features and ecosystems may be affected by the
project including how current Minnesota climate trends and anticipated climate change in the general location of
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the project may influence the effects. Include a discussion on introduction and spread of invasive species from the
project construction and operation. Separately discuss effects to known threatened and endangered species.
No Build Alternative
The No Build Alternative would not result in any impacts to identified fish, wildlife, plant communities, rare
features, and ecosystems.
Preferred Alternative
Possible effects to fish, wildlife, and known threatened and endangered species include possible noise and
vibration impacts and habitat impacts from construction and associated clearing of vegetation and trees.
Construction of the bridge would include direct and permanent impacts to the aquatic habitat within the
footprint of the existing and the proposed piers. The potential noise and vibrational impacts would be limited to
the period of bridge construction, see Section 4.1.19 Noise.
Bridge work, tree removals, and hibernacula impacts (rock cuts, roadway construction, percussives, vibration)
are anticipated to impact bat species that occur within the project area. Ground disturbances which include tree
and vegetation removal are anticipated to impact the rusty-patched bumble bee (RPBB) (Bombus affinis).
Habitat/wetland disturbances and active construction are anticipated to impact turtle species. In-stream work
including bridge demolition, causeway and pier construction, and barge utilization is anticipated to impact
mussel and fish species. However, conservation measures are proposed with the project to minimize or mitigate
impacts for all species (see Section 4.1.14.4 Avoidance, Minimization, and/or Mitigation).
Tree Clearing
While approximately 3.72 acres of tree removals are currently anticipated, up to 5.0 acres may be required due
to contractor access, constructability needs, and other unforeseen requirements. These tree removal estimates
differ slightly from the quantities developed during the alternatives analysis process which occurred from 2022
to 2023. These differences are due to the refined design which has since occurred for the Preferred Alternative
(Build Alternative B). These removals may indirectly impact federal and state protected bat species such as the
NLEB, TCB, LBB, and BBB. Most of the tree removal is anticipated to be within 100 feet of the existing roadway
and a small fraction (0.03 acre) is anticipated to be between 100 to 300 feet from the existing roadway. No tree
removal is anticipated to be greater than 300 feet from the roadway. Tree clearing will occur along the St. Croix
River at the bridge abutments and along the Wisconsin bluff. The Biological Assessment in APPENDIX K
(Biological Assessment) includes a figure illustrating the anticipated tree removal. Among the trees anticipated
to be removed are oak and ash trees. Section 4.1.14.4 Avoidance, Minimization, and/or Mitigation discusses the
post-construction landscaping plan.
Ground Disturbance
Approximately 6.0 acres of total ground disturbance is anticipated with the project. Upland construction
activities include tree/vegetation removal, bluff impacts, equipment staging, and other general construction
activities. Some areas along the project where improvements are proposed will be cut/filled or retained with
retaining walls for the proposed bridge.
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In-Water Construction
In-water construction activities which would occur in the St. Croix River and may directly impact aquatic species
include:
• Construction of temporary causeways in the river
• Barge spudding and fleeting
• Dredging of the river bottom
• Installation of cofferdams
• Operation of heavy equipment and general construction activities within the river for bridge demolition
and construction
In-water construction activities may indirectly affect aquatic species through:
• Temporary increases in turbidity and siltation because of construction activities that may impact mussel
feeding and respiration;
• Temporary altered hydraulic regimes and flow because of causeway installation and other in-stream
work activities that may result in riverbed scour, sedimentation, and other impacts to mussel habitat;
• Temporary alterations of fish host behavior because of in-stream work activities that may interfere with
mussel reproduction;
• Introducing or increasing populations of aquatic invasive species (e.g., zebra mussels (Dreissena
polymorpha)) in the area via inadequate construction equipment preventative measures prior to
equipment introduction to the waters of the St. Croix River.
During construction, an in-water impact area of at least 2.3 acres is anticipated, though the area could be as
large as 3.9 acres. The (up to) 3.9 acres of in-water area would include direct and indirect impacts. Details
regarding these areas can be found in the Constructability Report in APPENDIX E (Constructability Report) and
the Biological Assessment in APPENDIX K (Biological Assessment).
River velocities are anticipated to be impacted during construction of the project. Causeways will be used for
bridge demolition and construction and will narrow the area/opening of river flow, which would increase river
velocities compared to existing conditions. Increases in river velocities would impact the ability for fish species
to migrate through the project area and spawn upstream of the Hwy 243 Bridge. The project proposes a
minimum 90-foot gap between causeways with two additional 10-foot openings in the causeways to improve
river flow. A hydraulic analysis has been prepared for the bridge construction condition with two causeways in
the St. Croix River using a HEC-RAS 2D model. See the completed Temporary River Impact Analysis
Memorandum in APPENDIX H (Floodplain Assessment) or refer to Section 4.1.12.2 Describe effects from project
activities on water resources and measures to minimize or mitigate the effects below. Floodplains.
Initial 2D modeling results without scour indicate river velocities would increase by approximately 2 feet per
second (fps) compared to existing conditions for the baseline scenario during construction (i.e., summer median
event condition prior to overtopping). The baseline condition velocity with the two causeways with the 90-foot
center opening is projected to be 3.3 fps. In general, velocities greater than 3 fps can restrict fish movement
(depending upon species). Additional hydraulic analyses accounting for river scour with the causeways will be
completed and provided to MnDNR and WisDNR as part of the permitting process. Opportunities to minimize
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the increase in river velocities during construction to allow for fish passage will be evaluated in final design and
permitting.
The proposed Hwy 243 Bridge removes one pier from the St. Croix River compared to the existing structure.
River velocities at the Hwy 243 Bridge are expected to decrease compared to existing conditions, after
construction of the project. The proposed bridge would not create a permanent impact or barrier to fish passage
and migration. See the hydraulic analysis in APPENDIX H (Floodplain Assessment).
MnDNR maintains a hydroacoustic receiver in the St. Croix River downstream of the Hwy 243 Bridge. This
hydroacoustic receiver is used by MnDNR to track tagged fish in the river. The hydroacoustic receiver is within
the bridge construction work zone. MnDOT will coordinate with MnDNR prior to the start of construction to
relocate the hydroacoustic receiver downstream of the project. MnDNR will replace the hydroacoustic receiver
back to its original location following construction.
Federally Listed Species
MnDOT, on behalf of FHWA, requested concurrence from USFWS in a Section 7 Biological Assessment dated
February 23, 2024 (see APPENDIX K (Biological Assessment)). In this document, effect determinations were
made on 11 species of concern or critical habitats. The following determinations were made:
• Gray wolf (Canis lupus) – may affect, not likely to adversely affect.
• Tricolored bat (Perimyotis subflavus) – provisional determination of may affect, likely to adversely affect.
FHWA requested formal conferencing with the USFWS on the Tricolored bat. Not likely to jeopardize.
• Northern long-eared bat (Myotis septentrionalis) – may affect, likely to adversely affect.
• Whooping crane (Grus americana) – no effect.
• Higgins eye pearlymussel (Lampsilis higginsii) – may affect, likely to adversely affect.
• Snuffbox (Epioblasma triquetra) – may affect, likely to adversely affect.
• Spectaclecase (Cumberlandia monodonta) – may affect, likely to adversely affect.
• Winged mapleleaf (Quadrula fragosa) – may affect, likely to adversely affect.
• Salamander mussel (Simpsonaias ambigua) and proposed Critical Habitat – provisional determination of
may affect, likely to adversely affect. FHWA requested formal conferencing with the USFWS on the
Salamander mussel and proposed Critical Habitat. Not likely to result in adverse modification/destruction
of Critical Habitat.
• Rusty patched bumble bee (Bombus affinis) – may affect, likely to adversely affect.
• Monarch butterfly (Danaus plexippus) – candidate species; no jeopardy.
Avoidance, minimization, and mitigation measures related to federally protected species impacts are presented
in Section 4.1.14.4 Avoidance, Minimization, and/or Mitigation and in the Environmental Management Plan in
APPENDIX F (Environmental Management Plan).
Migratory Birds and Bald Eagles
The WisDNR identified this project as having the potential to impact migratory birds. Due to the evidence of
protected bird nests on the Hwy 243 Bridge, it is assumed that they may be impacted by the project. Based on
the scope of work and evidence of nests on the bridge, the alternatives evaluation process for this project
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included considerations for migratory birds. Conservation measures regarding migratory birds have been
identified based on standard commitments and are detailed in Section 4.1.14.4 Avoidance, Minimization, and/or
Mitigation and the Environmental Management Plan (see APPENDIX F (Environmental Management Plan) ).
Bald eagles (Haliaeetus leucocephalus) are protected by the Bald and Golden Eagle Protection Act. No bald eagle
nests are known within the project limits. An additional bald eagle survey is planned prior to construction of this
project. However, if a bald eagle nest is discovered during Project activities, the contractor will immediately
report Bald Eagle nests to the Department’s wildlife ecologist,
https://www.dot.state.mn.us/environment/wildlife.html.
Minnesota Listed Species
Though conservation measures are proposed to minimize impacts to Minnesota listed species, incidental take of
several Minnesota state-listed species is anticipated, including mussels, fish, turtles, and plant species. Incidental
take permits with the MnDNR will be applied for, as applicable. These include:
• Fish
o State-endangered crystal darter (Crystallaria asprella)
o State-threatened black buffalo (Ictiobus niger)
o State Special Concern gilt darter (Percina evides)
o State-threatened pugnose shiner (Notropis anogenus)
o State-threatened paddlefish (Polyodon spathula)
• Turtles
o State-threatened wood turtle (Glyptemys insculpta)
o State-threatened Blanding’s turtle (Emydoidea blandingii)
MnDOT reviewed the project area for two state-listed plant species: butternut (Juglans cinerea) and bog
bluegrass (Poa paludigena). Butternut was not observed in the project area and no impacts to this species are
anticipated. Bog bluegrass is not anticipated to occur in the project limits. Additional surveys for bog bluegrass
will be completed by MnDOT in summer 2024. If bog bluegrass is observed within the project limits, then survey
results will be provided to MnDNR and conservation measures will be identified. If necessary, MnDOT will apply
for an incidental take permit from MnDNR.
Wisconsin Listed Species
The mussel surveys conducted in 2020 and 2023 considered both Minnesota and Wisconsin listed species.
Incidental take of Wisconsin state-listed threatened or endangered mussel species is anticipated. Incidental take
permits will not be required for special concern species. The WisDNR’s Endangered Resources Review resulted in
possible impacts to the following threatened, endangered, or species of special concern:
• Bats
o State-threatened northern long-eared bat (Myotis septentrionalis)
o State-threatened big brown bat (Eptesicus fuscus)
o State-threatened tricolored bat (Perimyotis subflavus)
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o State-threatened little brown bat (Myotis lucifugus)
o Special concern bat hibernaculum
• Fish
o State-threatened river redhorse (Moxostoma carinatum)
o State-endangered crystal darter (Crystallaria asprella)
o State-threatened black buffalo (Ictiobus niger)
o State-threatened blue sucker (Cycleptus elongatus)
o State-threatened shoal chub (Macrhybopsis hyostoma)
o State special concern lake sturgeon (Acipenser fulvescens)
o State special concern American eel (Anguilla rostrata)
• Mussels
o State-endangered elephant ear (Elliptio crassidens)
o State special concern elktoe (Alasmidonta marginata)
o State-endangered spectaclecase (Cumberlandia monodonta)
o State-endangered snuffbox (Epioblasma triquetra)
o State-threatened wartyback (Quadrula nodulata)
o State-threatened fawnsfoot (Truncilla donaciformis)
o State-threatened monkeyface (Theliderma metanevra)
o State-endangered butterfly (Ellipsaria lineolata)
o State-endangered winged mapleleaf (Quadrula fragosa)
o State threatened buckhorn (Tritogonia verrucosa)
o State-endangered Higgins eye pearlymussel (Lampsilis higginsii)
o State-threatened wood turtle (Glyptemys insculpta)
• Turtles
o State special concern Blanding's turtle (Emydoidea blandingii)
The WisDNR identified the project area as a valuable wildlife corridor and requested that habitat connectivity be
addressed with the project, which is detailed in the Section 4.1.14.4 Avoidance, Minimization, and/or Mitigation.
An Endangered/Threatened Species Incidental Take Authorization is anticipated from the WisDNR prior to
construction. In completing the permit(s), appropriate compensatory mitigation measures would be developed.
It has not yet been determined if broad incidental take or individual take permits will be required; this will be
determined in consultation with WisDNR during the permitting process.
Minnesota Biological Survey - Sites of Biodiversity Significance
While there are areas within this project area that may not need direct protection, the MnDNR concern is that
soil disturbance, incidental herbicide exposure, hydrologic alterations, competition from non-native species, or
sod-forming grasses can all lead to degradation of these areas. Significant impacts are not anticipated at this
time, however, coordination on these environmentally sensitive areas will continue between various local, state,
and federal stakeholders, to ensure that no significant impacts result from the proposed project.
Invasive Species
Curly leaf pondweed (Potamogeton crispus) and Asiatic clams (Corbicula fluminea) are aquatic invasive species
that occur in the project, as identified by the WisDNR. Emarald ash borer (Agrilus planipennis) and oak wilt
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(Bretziella fagacearum) have also been identified as a WisDNR concern within the project area. Invasive carp
have been identified by the USCG in the St. Croix River south of Taylors Falls. The USCG have also found zebra
mussels (Dreissena polymorpha) and Eurasian milfoil (Myriophyllum spicatum) downstream of the project study
area in Lake St. Croix.
Noxious Weeds
Noxious weeds have been identified along the Hwy 243 corridor in the past, including wild parsnip, which can be
a safety concern to those working in the areas where it may be growing.
Climate Change Impacts
Natural resource impacts due to climate change are anticipated to vary between ecosystems, populations, and
species. Both positive and negative impacts are projected, and these impacts depend on the ecosystem,
population, or species. Fish, wildlife, and plant species that are more mobile may respond to climate change by
altering their ranges of where they occur based on adaptation and survival in changing conditions. Species that
are less mobile may not have the capacity to migrate, therefore other interventions may be needed (e.g.,
assisted migration). Protecting population refuges and movement/migration corridors will be of utmost
importance in the world of wildlife conservation, and efforts to increase landscape permeability (quality of
heterogeneous land area in providing passage for animals), are expected to be of key significance in a changing
climate.52
MnDOT seeks to maintain and enhance ecological connectivity on its projects through both programmatic
approaches, such as the standard use of wildlife passage benches under bridges spanning public waters, and
through project-specific designs components, such as multi-use structures and dedicated wildlife crossing
structures and fencing. Maintaining and enhancing ecological connectivity reduces the barrier effect roads have
on individual animals, populations, and ecosystems, which in turn improves natural resource resiliency. These
types of improvements are being integrated with this project and are detailed further in the following section.
4.1.14.4 Avoidance, Minimization, and/or Mitigation
Identify measures that will be taken to avoid, minimize, or mitigate the adverse effects to fish, wildlife, plant
communities, ecosystems, and sensitive ecological resources.
All of the following conservation measures that are proposed to avoid, minimize, and/or mitigate adverse
effects to fish, wildlife, and plant communities will also be documented and implemented through the
Environmental Management Plan for the project (see APPENDIX F (Environmental Management Plan)).
52 Jonathan R. Mawdsley, Robin O'Malley and Dennis S. Ojima. A Review of Climate-Change Adaptation Strategies for Wildlife
Management and Biodiversity Conservation. Accessed in April 2024 and available at https://www.jstor.org/stable/40419680.
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General Project Level Conservation Measures
All interested parties (e.g., MnDOT, WisDOT, USFWS, NPS, etc.) will be invited to attend preconstruction
meetings, joint site walks and inspections, and similar activities. These meetings will be scheduled as allowed
considering personnel availability and construction milestones.
All contractors will be required to attend an ‘environmental regulations’ training course ahead of the start of
construction.
The project commits to implementing and adhering to an erosion and sediment control plan that will outline
measures implemented to reduce construction site erosion, sedimentation, and subsequent discharges into the
St. Croix River. The erosion and sediment control plan may include, but is not limited to, a vegetation
management plan, SWPPP, spill prevention plan, and dust control plan. The erosion and sediment control plan
will be approved in consultation with the Minnesota Department of Natural Resources, Wisconsin Department
of Natural Resources, the U.S. Army Corps of Engineers, the Minnesota Pollution Control Agency, the MnDOT
Office of Environmental Stewardship, and other effected parties prior to start of construction.
Tree species native to the St. Croix River Valley will be replanted as part of the post-construction landscaping
plan. This is consistent with the intent of the Visual Quality Manual (VQM). The post-construction landscaping
plan will be implemented within two years after completion of construction.
Fisheries
The project anticipates that causeways extending from both the Minnesota and Wisconsin banks will be
required. The project will maintain a mid-channel opening in the causeway to maintain river flows and fish
passage and the causeways will include additional embedded culverts for additional water conveyance and fish
passage. The proposed causeway design includes a 90-foot-wide center opening with two additional 10-foot
openings. These measures are anticipated to address the potential slowing of Osceola Creek, as well as reduce
the deposition of sediment near the confluence of Osceola Creek and the St. Croix River.
Work in-water exclusion dates to allow for fish passage and migration range from March 15 to June 15 in
Minnesota and March 1 to June 15 in Wisconsin. It is anticipated that the project cannot entirely avoid in-water
work during these restriction dates and exemptions will be required from MnDNR and WisDNR. An
Endangered/Threatened Species Incidental Take Authorization is anticipated from the WisDNR prior to
construction. In completing the permit(s), appropriate compensatory mitigation measures would be developed.
It has not yet been determined if broad incidental take or individual take permits will be required; this will be
determined in consultation with WisDNR during the permitting process. Additional conservation measures for
fisheries, if necessary, will be identified in consultation with MnDNR and WisDNR in final design and permitting.
Freshwater Mussels
The project may result in impacts to mussels; however, the project will not result in jeopardy to the continued
existence or recovery of mussel species. Impacts to mussels have been minimized through the alternatives
evaluation process (i.e., construct on existing bridge alignment), bridge type selection (i.e., pier placement to
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avoid mussel habitat), in-water work considerations, and implementation of the conservation measures
described below.
The primary conservation measure used to minimize effects on freshwater mussels will be a systematic
relocation of all individuals from the area of temporary and permanent in‐stream impacts to a suitable Recipient
Site beyond the project’s impacts. Relocation efforts will occur ahead of construction; as construction is
anticipated to begin Fall 2026, relocation efforts are anticipated for Summer/Fall 2026, during low‐water
conditions. Relocation of mussels from within the in‐stream impact area will be accomplished by qualified
biologists and will follow a USFWS, MnDNR, and WisDNR – approved relocation plan. The Mussel Relocation
Plan will be submitted to the USFWS and will be approved prior to construction. The relocation plan will
incorporate a post‐construction freshwater mussel survey to assess the condition of individuals moved during
the relocation and to determine any post‐construction recolonization.
All mussels relocated from the in-water work area at the Hwy 243 Bridge will be relocated to another site
(recipient site) near the project area in the St. Croix River. The specific location for the recipient site will be
determined as part of the pre-construction relocation plan development. In general, the preferred location for
the recipient site is upstream of and as close to the project area as possible in an area of suitable mussel habitat.
Additional conservation measures regarding mussels, as outlined in the BA, include:
• Restoration of the St. Croix River streambed to original elevation where earthen causeways are
constructed.
• Project will implement to MnDNR best practices for preventing spread of aquatic invasive species per
the Project’ MnDNR Public Waters Work Permit
• All contractor(s) will be required to implement and adhere to an aquatic invasive species
management/decontamination plan to ensure that no aquatic invasive species are introduced into the
St. Croix River through construction equipment (e.g., barges, boats, heavy machinery, etc.).
• Contractors must submit the aquatic invasive species management/decontamination plan to MnDOT’s
Office of Environmental Stewardship and USFWS for approval prior to any in‐stream work.
• Stormwater runoff from the existing Hwy 243 Bridge and approach roadways are currently discharged
directly into the St. Croix River without any treatment. The proposed action includes construction of a
stormwater basin (i.e., wet pond) on the Minnesota side of the St. Croix River adjacent to the Osceola
Landing entrance. Stormwater runoff from the proposed bridge surface will be conveyed by curb and
gutter and storm sewer to this stormwater basin for treatment prior to discharge. The stormwater basin
will be designed to National Urban Runoff Program (NURP) standards and would help reduce pollutant
loading to the St. Croix River compared to existing conditions.
• To compensate for unavoidable impacts to a mussel bed with federally listed mussel species, the project
commits to transferring funds into a mussel in-lieu fee/pooled fund or other compensatory mitigation
program. The specific program to be used will be determined in consultation with the USFWS. Although
this measure will not minimize effects to mussel species within the project area, it will help offset those
consequences at suitable habitat elsewhere in the states of Minnesota and Wisconsin. This funding may
be used for mussel propagation, habitat creation or restoration, research, or other activities related to
freshwater mussel conservation. Funds transferred into the compensatory mitigation program will be
under the jurisdiction of USFWS and will be used in the St. Croix River.
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• The USFWS used a mussel bed density of 3.45 individuals/m2 based on previous mussel surveys in the
action area and the St. Croix River to calculate the compensatory mitigation required to offset adverse
impacts across 15,621 m2 of suitable in‐stream mussel habitat within the action area. FHWA/MnDOT will
work with the USFWS to use the most updated version of the mussel mitigation HEA model developed
by the USFWS to determine a funding amount.
• FHWA/MnDOT will work with the USFWS to develop a funding agreement.
• Within two years of the issuance of the Biological Opinion, and prior to the start of construction, MnDOT
will transmit payment based on the terms of the funding agreement, plus any administrative fees
associated with managing the funds.
More detailed information on freshwater mussel conservation measures can be found in Section 6 of the
Biological Assessment (see APPENDIX K (Biological Assessment)).
Bats
Inspection of buildings proposed for demolition and culvert replacements will occur for the northern long-eared
bat, the tricolored bat, the big brown bat, and the little brown bat following USFWS survey standards. For
WisDNR buildings and bridges, this means a yearly bi-yearly inspection, respectively. For USFWS buildings and
bridges, this means an inspection every two years for both.
Because the proposed project is within ¼ mile of a known bat hibernaculum with this species present, it is
recommended to proceed with the option that results in the least amount of tree removal and bluff disturbance.
If grading were to occur within 500 feet of the cave, that activity needs to be completed when bats are not
hibernating (May 10 - August 31) so potential collapses associated with work and vibrations do not affect the
bats. To avoid impacts to roosting bats outside of the cave, tree clearing will occur from November 15 –March
31, inclusive.
The need for a bat house will be determined in consultation with WisDNR as part of the WisDOT/WisDNR
Cooperative Agreement process.
The following conservation measures were identified as part of this project’s Biological Assessment for federally
listed bats and will benefit additional state listed and common bat species:
• All commitments will be included in the project’s Environmental Management Plan (see APPENDIX F
(Environmental Management Plan)).
• To the maximum extent practicable, the project has been designed to minimize the project footprint,
minimize habitat removal, utilize existing infrastructure and disturbed areas, and where possible, co-
locate project features (e.g., place trails adjacent to existing roads).
• All tree clearing and grubbing will occur during the winter months (November 15 to March 31,
inclusive). Tree removal will be limited to those specified in project plans and it will be ensured that
contractors understand tree clearing limits and how the limits are marked in the field (e.g., install bright
colored flagging/fencing prior to any tree clearing to ensure contractors stay within clearing limits).
o If the project schedule allows, tree clearing and grubbing may occur December 1 to February
28, inclusive to accommodate unseasonable warm fall and/or spring.
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• Impacts to bluffs within the project area will be minimized to the extent practicable.
• Impacts to bluffs will occur when bat species are not anticipated to be utilizing the hibernaculum (bluff
impacts allowed May 10 to August 31, inclusive), eliminating direct disturbances to hibernating bats.
• Impacts to bluff areas will be completed via ‘mechanical scaling’ the bluff face (e.g., reshaping bluff
face). No explosives will be used, limiting potential indirect impacts to bat hibernacula.
• While ‘mechanical scaling’ of the bluff face using an excavator bucket is the preferred method to
reshape the bluff face, hydraulic hammering may be required in areas of more resilient rock and will be
limited to the extent practicable.
• Existing bridge expansion joint glands will be sliced on the bridge in the spring ahead of bridge
demolition activities (e.g., before April 1) and ahead of the bat pupping season, to increase airflow and
moisture to modify the microclimate within the joints to deter bats from utilizing the joints ahead of
bridge demolition activities.
• On‐site personnel must use best management practices, secondary containment measures, or other
standard spill prevention and countermeasures to avoid spills and impacts to possible hibernacula.
• Where practicable, a 300‐foot buffer will be employed to separate fueling areas and other major
containment risk activities from caves, sinkholes, losing streams, and springs in karst topography.
• The project is not anticipating the removal of documented NLEB roost trees.
• The project will utilize properly muffled equipment to minimize noise impacts.
• Back‐up alarms on equipment (i.e., tweety‐bird alarms) will be muffled during the pupping season (June
1 to August 15, inclusive) and other safety measures will be used to minimize noise impacts.
• Installation of new or replacement of existing permanent lights must use downward‐facing, full cut‐off
lens lights (with same intensity or less for replacement lighting); or for those transportation agencies
using the BUG system developed by the Illuminating Engineering Society, be as close to 0 for all three
rating with a priority of “uplight” of 0 and “backlight” as low as practicable.
• Any temporary lighting used will be directed away from wooded areas during the bat active season
(April 1 to November 14, inclusive), or when bats are present.
• The contractors working in areas of known or presumed bat habitat will be made aware of all FHWA
environmental commitments, including all applicable avoidance and minimization measures (AMMs).
Bat sightings (including sick, injured, and/or dead bats) on the project must be reported to the MnDOT
OES wildlife ecologist (612‐741‐7678) and the Minnesota‐Wisconsin Ecological Services Field Office
(dawn_marsh@fws.gov; 612‐283‐8054) within 24 hours.
• Appropriate take permits will be acquired for impacts to Wisconsin-listed bat species.
• Bat house(s) may be installed near the bridge to encourage off-structure roosting.
Bees
The following conservation measures were identified as part of this project’s Biological Assessment (BA) for
federally listed bees and will benefit additional state-listed and common bee species:
• Revegetating a minimum of 4.0 acres with pollinator‐friendly native seed mixes (see Table 7 of the BA in
APPENDIX K for a list of preferred herbaceous plant species nectar sources by the RPBB in the Great
Plains States that are also present in the proposed seed mixes). Native seed mixes and acreages of each
mix will be determined during further design phases and will follow guidelines outlined in the 2023
MnDOT Seeding Manual (MnDOT, 2023). Proposed seed mixes include:
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o Native seed mixes appropriate for use in upland areas in full sun above the floodplain (e.g.,
MnDOT Seed Mix #35‐241 [Mesic Prairie General] or similar). This proposed seed mix is common
in areas of mesic soil conditions and includes seven species within Table 7 of the BA (APPENDIX
K).
o Native seed mixes appropriate for use in non‐wetland areas adjacent to the St. Croix River which
are likely to experience seasonal flooding (e.g., MnDOT Seed Mix #34‐261 [Riparian South and
West] or similar). This proposed seed mix contains both grasses/sedges (graminoids) and forbs,
including five species within Table 7 of the BA (APPENDIX K).
o Native seed mixes appropriate for use along the edges of stormwater facilities (e.g., MnDOT
Seed Mix # 33‐261 [Stormwater South and West] or similar). This proposed seed mix contains
two species within Table 7 of the BA (APPENDIX K).
• Temporary seeding must not include smooth brome or other similarly aggressive non‐native species that
may be detrimental to the future establishment of native vegetation.
• Local origin, or seed as closely related as possible, native seed mixes may be used.
• Project must include mowing and spot weed control to establish seeded vegetation, as described in the
MnDOT Seeding Manual.
• Requiring the Contractor to prepare and submit a noxious and invasive weed management plan to the
Project Engineer prior to the start of construction, which helps prevent the spread of noxious and
invasive weed species and maintains greater plant diversity. The plan must be reviewed and approved
by MnDOT OES Roadside Vegetation Management Unit prior to the start of construction.
• Requiring the contractor to apply herbicide, if used, in a targeted fashion (i.e., cut‐stem application,
hand applications, directly spraying targeted plant) using handheld sprayers to limit effects of herbicide
beyond targeted plant species.
• Prohibiting the use of neonicotinoid pesticides.
Turtles
Wildlife crossings are being implemented with the project on the Minnesota side of the St. Croix River, in order
to minimize impacts to wood turtles (Glyptemys insculpta) and Blandings turtles (Emydoidea blandingii). The
project is anticipating to construct two culverts under Hwy 243 west of the Osceola Landing entrance. These
culverts would function as wildlife crossings. Fencing is anticipated to be installed along Hwy 243 to channel
wildlife to these culverts. Access to Osceola Landing would be maintained when the wildlife crossing culverts are
installed. Two options for maintaining access to Osceola Landing include constructing the wildlife crossings after
bridge construction is complete. Access to Osceola Landing would be provided from Wisconsin to the east. A
second option includes maintaining traffic on one side of Hwy 243 with flagging operations while the culverts
are installed. A final decision regarding timing of wildlife crossing construction and methods (e.g., open-cut vs.
one side of the roadway at a time) will be made in final design.
Wildlife fencing is also proposed on the north side of the proposed stormwater basin in Minnesota (located east
of the Osceola Landing entrance), to prohibit movement from the basin to Hwy 243, thereby minimizing risk of
wildlife road mortality.
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Wood Turtle
Suitable habitat for the wood turtle (Glyptemys insculpta) appears to be present within 300 meters of the St.
Croix River. Therefore, to follow the Wood Turtle Broad Incidental Take Permit/Authorization (BITP/A) from the
WisDNR, the measures below will be followed:
• No ground disturbance, heavy equipment operation or supply/equipment storage within nesting habitat
(exposed sand or gravel areas within 200 feet of a suitable stream/river) during the nesting season (May
20 – September 18) unless herp exclusion fencing has been installed or the habitat has been made
unsuitable outside of these dates.
• Aggregate surfacing must be placed on all rip-rapped areas and slopes above the Ordinary High Water
Level (OHWL) to fill voids per MnDOT specifications and special provisions (2118). Project personnel
(individuals on site for project purposes rather than for the purpose of looking for turtles) must move
any turtles observed on site out of harm’s way.
• Land conversion activities (e.g., new development, road expansion, etc.) that permanently alter or
reduce habitat are not allowed unless avoidance measures are put into place.
• Active dates are updated frequently in the spring and fall and will be checked here:
https://dnr.wi.gov/topic/Wildlifehabitat/HerpRegulations.html.
The BITP/A for the wood turtle also includes a time of year restriction for in-stream work. In-stream work and
drawdowns during the maximum overwintering period (October 1-April 30) is not allowed. In-stream work
includes, but is not limited to, streambank/rip-rap installation, causeway installation and removal, open cut
trenching, barge spudding, and dredging. An incidental take permit for wood turtle will be acquired from
WisDNR prior to construction if the project cannot avoid in-water work during the time of year restriction dates.
Blanding’s Turtle
The WisDNR determined that Blanding’s turtle (Emydoidea blandingii) conservation measures are appropriate
for this project, which includes the following:
• Overwintering areas – Blanding’s turtles typically overwinter in wetlands or water bodies with standing
water at least three feet deep. Because this species can be found in these wetlands and water bodies
throughout the year, impacts to these wetlands and waterbodies should be minimized at all times.
• Non-overwintering areas – for wetlands/water bodies shallower than three feet at the deepest point,
work will be conducted outside of the Blanding’s turtle’s active season (March 5 – November 15). The
installation and maintenance of exclusion fencing using the WisDNR Amphibian and Reptile Exclusion
Fencing Protocol will be used during this period and the exclusion fencing will be installed between
November 16 and March 4. In order for work to be conducted within the fenced area at any time of
year, the fencing will be maintained.
• Upland nesting habitat – work will be avoided in suitable upland nesting habitat (sandy and/or well-
drained soils) within 275 meters (900 feet) of a wetland or water body during the Blanding’s turtle’s
nesting period (May 20 – October 15). The installation and maintenance of exclusion fencing using the
WisDNR Amphibian and Reptile Exclusion Fencing Protocol will be used during this period as and the
exclusion fencing will be installed between October 16 and May 19. In order for work to be conducted
within the fenced area at any time of year, the fencing will be maintained.
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Incidental take permits will be acquired from the MnDNR and WisDNR for impacts to threatened and
endangered species. During the permit approval process, additional mitigation measures (compensatory or
otherwise) will be developed, as needed.
Migratory Birds
The existing bridge is known to harbor nesting birds that may be protected under the Migratory Bird Treaty Act
(MBTA). MnDOT standard commitments for projects that may impact migratory birds will be followed.
Commitments may include:
• Contractor will cover soil stockpiles when any surface of a stockpile is not in use for 48 hours or longer.
• Contractor must prevent bird nesting by either covering that surface with fabric or tarps or by grading
that surface to a slope no steeper than 65 degrees.
• If a nest or nests are encountered that have eggs and/or live young, photograph the nest, avoid work in
that location and immediately contact the Department’s wildlife ecologist,
https://www.dot.state.mn.us/environment/wildlife.html.
• Contractor will prevent birds from establishing active nests (those containing eggs or live young) until
such time as the construction activities are completed, or no longer threaten the nests.
• Contractor will remove inactive nests from the previous nesting season and remove nests that are being
established but before they are active (i.e., before they have eggs or young).
o This action requires frequent inspections and nest removals to prevent nests from being
constructed and becoming active. Allow no more than two Calendar days between inspections
and removals. Daily inspections and removals may be needed in areas with frequent bird use.
Nest removal must start prior to April 15.
• If impacts to nesting birds are unavoidable, appropriate depredation permit(s) will be acquired from
USFWS ahead of construction.
Minnesota Biological Survey – Sites of Biodiversity Significance
All pertinent stakeholders will be closely consulted with to ensure that proper precautions are taken, where
necessary, to minimize impacts to sites of biodiversity significance and to ensure that proper and acceptable
restoration (methods and materials) of disturbed areas. Requirements pertaining to these environmentally
sensitive areas will be followed. Native seeds will be used in those locations where restoration or replacement is
required. Temporary fence will be place along the limits of construction (based on MnDOT Standard
Specification 2572.3A.1). Since the project will require the use of temporary fence, it will be clearly called for in
the construction plans, and the Standard Plan 5-297.302 will be included in the plan package.
Sites of Biodiversity Significance will be identified as an ‘Area of Environmental Sensitivity’ (AES) on plans. This
designation helps assure special protection during construction though MnDOT Standard Specifications for
Construction #1717 (Air, Land, and Water Pollution), #2573 (Stormwater Management), and #2575 (Establishing
Vegetation and Controlling Erosion). MnDNR AES best practices guidance (based on MnDOT Construction
Specification 2572.3) will be followed.
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Invasive Species
The St. Croix River will be identified as ‘designated infested waters’ on project plans and provisions. While
invasive carp are generally not an issue related to bridge construction activities, construction provisions shall be
written to state that all incoming equipment to be placed into or near the water must have documentation that
they have been cleaned prior to transport to the site. The MnDNR concern is to not introduce species such as
zebra mussels (Dreissena polymorpha), quagga mussels (Dreissena bugensis), New Zealand mudsnails (Perna
canaliculus), faucet snails (Bithynia tentaculata), or spiny waterfleas (Bythotrephes longimanus). See
https://files.dnr.state.mn.us/publications/ewr/invasives/ais/best_practices_for_prevention_ais.pdf for
decontamination of construction equipment will be followed prior to equipment arrival on-site.
In their review of the project, the WisDNR also included considerations of invasive species. This segment of the
St. Croix River contains populations of Curly-leaf Pondweed (Potamogeton crispus) and Asiatic Clams (Corbicula
fluminea), which are aquatic invasive species. The project also has the potential for spreading terrestrial
invasives such as the Emerald Ash Borer (EAB) (Agrilus planipennis) beetle. While it is legal to move ash debris or
wood throughout Wisconsin, it is a best management practice to prevent spreading the beetle to areas where it
is not yet established. Invasive carp have been identified by the USCG in the St. Croix River south of Taylors Falls.
The USCG have also found zebra mussels (Dreissena polymorpha) and Eurasian milfoil (Myriophyllum spicatum)
downstream of the project study area in Lake St. Croix.
See WisDNR Best Management Practices at https://dnr.wisconsin.gov/topic/Invasives/bmp to prevent the
introduction and spread of invasive terrestrial or aquatic species will be implemented, such as boat, gear, and
equipment decontamination and disinfections. These will be implemented to avoid the spread of invasive
species as outlined in Wis. Adm. Code NR 40 and MnDNR Operational Order 113.
WisDOT policy regarding preventing transmission of oak wilt will be followed.
Noxious Weeds
MnDOT Standard Specification 2575.J contains contractor requirements regarding weed control on all MnDOT
projects and will be followed.
4.1.15 Historic Properties
Describe any historic structures, archeological sites, and/or traditional cultural properties on or in close proximity
to the site. Include: 1) historic designations, 2) known artifact areas, and 3) architectural features. Attach letter
received from the State Historic Preservation Office (SHPO). Discuss any anticipated effects to historic properties
during project construction and operation. Identify measures that will be taken to avoid, minimize, or mitigate
adverse effects to historic properties.
Because federal funding sources from FHWA are being pursued for the Hwy 243 Osceola Bridge Project, the
project is considered a federal undertaking and must comply with Section 106 of the National Historic
Preservation Act of 1966 (Section 106) and its implementing regulations. Section 106 requires federal agencies
to consider the effects of their undertakings on historic properties. Historic properties are any building,
structure, object, site, or district that is considered eligible for or listed in the NRHP. The MnDOT Cultural
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Resources Unit (MnDOT CRU), in partnership with WisDOT Cultural Resources Team (WisDOT CRT), has taken
the lead in assisting FHWA in the Section 106 process.
FHWA, as the lead federal agency for the proposed project, has authority to:
• Initiate the Section 106 process by determining whether the action is an undertaking and notifying the
SHPO, Indian tribes, and other consulting parties.
• Identify historic properties by determining an area of potential effect (APE), conducting surveys and
evaluating properties under NRHP criteria.
• Assess the effects of the undertaking on historic properties by applying the criteria of adverse effect and
consulting with SHPOs, the Office of the State Archaeologist (OSA), the Minnesota Indian Affairs Council
(MIAC), Indian tribes, other consulting parties and the public.
• Resolve any adverse effects by continuing consultation with Section 106 consulting parties to explore
measures that avoid, minimize, or mitigate the adverse effects, and develop a Section 106 Agreement to
document the agreed-upon measures.
The following section summarizes the historic properties investigations conducted for the project including
consultation efforts, development of an area of potential effects, and initial results of investigations. Additional
information on these investigations is included in the following reports, which are available upon request from
the project manager:
• Archaeological Literature Search for the Hwy 243 Osceola Bridge Project, Franconia Township, Chisago
County, Minnesota and Osceola, Polk County, Wisconsin (February 2021)
• Phase I Archaeological Survey for the Hwy 243 Osceola Bridge Project, Franconia Township, Chisago
County, Minnesota (October 2022)
• Phase I Archaeological Survey for the Hwy 243 Osceola Bridge Project, Osceola, Polk County, Wisconsin
(November 2022)
• Draft Architecture/History Literature Review and Proposed Area of Potential Effect, Osceola Bridge over
the St. Croix River, Chisago County, Minnesota and Polk County, Wisconsin (March 2021)
• Phase I Architecture/History Survey for the Osceola Bridge over the St. Croix River, Franconia Township,
Chisago County, Minnesota and Osceola, Polk County, Wisconsin (March 2022)
4.1.15.1 Consultation
On behalf of FHWA, MnDOT and WisDOT notified tribes who expressed interest in projects in this geographical
area and invited their participation in the Section 106 process pursuant to 36 CFR § 800.2I(2)(ii). MnDOT CRU
and WisDOT CRT contacted the following tribes in 2020 and 2021 regarding the project:
• Fort Peck Tribes
• Leech Lake Band of Ojibwe
• Mille Lacs Band of Ojibwe
• Santee Sioux Nation
• Shakopee Mdewakanton Sioux Community
• Turtle Mountain Band of Chippewa
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• Upper Sioux Community
• Fond du Lac Band of Lake Superior Chippewa
• Prairie Island Indian Community
No responses were received from the Tribal Nations contacted in 2020 and 2021. In February 2021, the Ho-
Chunk Nation of Wisconsin contacted MnDOT CRU and requested that they remain a consulting party for the
project and requested copies of the project’s archaeological reports for their files. APPENDIX J (Agency
Correspondence) includes MnDOT CRU’s tribal notification forms and the Ho-Chunk Nation of Wisconsin
response.
Any tribe may request to enter into consultation at any point during the Section 106 review. MnDOT CRU and
WisDOT CRT will notify all tribes who have expressed an interest in this geographic area of the identification of
any historic properties that may be of significance to them. Prior to the start of construction, MnDOT CRU in
consultation with the WisDOT CRT would develop an unanticipated discovery plan to define the process that
would be followed in the event of the discovery of new historic properties, new effects to identified historic
properties, and human remains and/or burial-related objects during project construction activities. The plan
would include information on what tribes would be notified and how they will be notified in the event of such
discoveries. MnDOT CRU and WisDOT CRT would provide tribes with the opportunity to review and comment on
the plan prior to finalizing it.
NPS requested to become a Section 106 consulting party in a letter to the MnDOT Project Manager in May 2021.
MnDOT CRU responded in a letter to NPS in August 2021 acknowledging NPS’s status as a consulting party in the
Section 106 process for the Hwy 243 Osceola Bridge Project. The USACE is also a consulting party under the
terms of the Statewide Programmatic Agreement (PA).
The consulting parties in the Section 106 review of the Hwy 243 Osceola Bridge Project include:
• Minnesota SHPO
• Wisconsin SHPO
• USACE
• NPS
• Ho-Chunk Nation of Wisconsin
4.1.15.2 Area of Potential Effects (APE)
An APE is the geographical area or areas within which an undertaking may directly or indirectly cause alterations
in the character or use of historic properties, if any such properties are present. The APE is influenced by the
scale and nature of the undertaking and must account for both direct and indirect effects, including permanent
and temporary effects. The APE encompasses the Hwy 243 right of way limits from approximately 2,000 feet
west of the St. Croix River in Minnesota to the WIS-35 intersection in Osceola. The APE included a 300-foot
buffer around the existing Hwy 243 Bridge. In April 2024, the APE was expanded in Minnesota to include areas in
the NPS Osceola Landing site that would be used for construction staging and access to the St. Croix River.
Architecture/history and archaeology surveys are summarized below in Section 4.1.15.3 Existing Conditions.
Survey limits encompassed a broad project study area along Hwy 243 from MN-95 in Minnesota to WIS-35 in
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Wisconsin. Architecture/history and archaeology surveys included a broad project study area because the
surveys were initiated prior to the identification of the Preferred Alternative and preliminary construction limits
for the project. The APE described above is within the project study area for architecture/history and
archaeology surveys.
4.1.15.3 Existing Conditions
Cultural resources investigations included file searches for previously identified resources, documentary
research to identify potential unrecorded resources, and field survey. Results of architecture/history and
archaeology surveys are summarized below.
Architectural History
Minnesota Results
The Phase I Architecture/History Survey for the Osceola Bridge over the St. Croix River, Franconia Township,
Chisago County, Minnesota and Osceola, Polk County, Wisconsin (March 2022) identified four properties in
Minnesota. Three properties built before 1977 and located within the APE in Minnesota were previously
determined not eligible within the past ten years. MnDOT CRU has determined that the fourth property built
before 1977 and located within the APE in Minnesota, Hwy 243 (XX-ROD-120), is not eligible for the NRHP.
Minnesota SHPO concurred with MnDOT CRU’s determination that Hwy 243 (XX-ROD-120) is not eligible for the
NRHP (see Minnesota SHPO correspondence dated October 11, 2023 in APPENDIX J (Agency Correspondence)).
Wisconsin Results
The Phase I Architecture/History Survey for the Osceola Bridge over the St. Croix River, Franconia Township,
Chisago County, Minnesota and Osceola, Polk County, Wisconsin (March 2022) identified one property in
Wisconsin. One residence was inventoried in Wisconsin. This property was determined not eligible for the NRHP.
Wisconsin SHPO concurred with the determination that this residence is not eligible for the NRHP (see WisDOT
Form DT1635 Section 106 Review Archaeological/Historical Information in APPENDIX J (Agency
Correspondence)).
Archaeology
Minnesota Results
The Phase I Archaeological Survey for the Hwy 243 Osceola Bridge Project, Franconia Township, Chisago County,
Minnesota (October 2022) describes one previously identified archaeological site and two new archaeological
sites in Minnesota. MnDOT CRU concluded that two of the sites are not eligible for listing in the National
Register. The third site is beyond the archaeology APE and no further investigation was warranted.
No concerns regarding properties of cultural significance in this area were brought forward to MnDOT or
WisDOT during initial tribal consultation efforts. One tribe, the Ho Chunk Nation, requested to be a consulting
party on the project, and have been sent copies of the cultural resource reports. The Ho Chunk Nation have not
expressed any concerns that the identified archaeological sites in Minnesota may be culturally significant.
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Wisconsin Results
The Phase I Archaeological Survey for the Hwy 243 Osceola Bridge Project, Osceola, Polk County, Wisconsin
(November 2022) describes two previously identified archaeological sites. No new archaeological sites were
identified along Hwy 243 in Wisconsin with the Phase I survey. The two previously identified archaeological sites
are outside of the archaeology APE and are avoided by the Hwy 243 Osceola Bridge Project.
4.1.15.4 Section 106 Finding
No Build Alternative
The No Build Alternative would not result in any impacts to identified historic properties.
Build Alternative
Minnesota Results
MnDOT CRU submitted the results of architectural history and archaeological investigations to the Minnesota
SHPO on September 12, 2023. MnDOT CRU determined that there would be “no historic properties” affected by
the Hwy 243 Osceola Bridge Project. The Minnesota SHPO responded on October 11, 2023 and concurred with
the no historic properties finding. See MnDOT CRU and Minnesota SHPO correspondence in APPENDIX J (Agency
Correspondence).
Wisconsin Finding
WisDOT submitted a project description and information regarding cultural resources investigations to the
Wisconsin SHPO in December 2023, including a “no historic properties” (historical or archaeological) in the APE
finding. Wisconsin SHPO agreed with the no historic properties finding on February 5, 2024. See the WisDOT
Form DT 1635 in APPENDIX J (Agency Correspondence).
4.1.16 Visual
Describe any scenic views or vistas on or near the project site. Describe any project related visual effects such as
vapor plumes or glare from intense lights. Discuss the potential visual effects from the project. Identify any
measures to avoid, minimize, or mitigate visual effects.
A Visual Impact Assessment (VIA) was conducted for the proposed project. The purpose of this assessment is to
evaluate the project’s impact on the relationship between viewers and the environment. Viewers include
neighbors who can see the project and travelers who use the roadway; and environment includes the natural,
cultural (e.g., built or ‘fabricated’), and/or project related components (e.g., geometrics and/or structural). The
following sections summarize the VIA. See APPENDIX L (Visual Impact Assessment) for the complete VIA.
4.1.16.1 Existing Conditions
There are several visual resources located near the Hwy 243 Bridge. The Area of Visual Effect (AVE) for
the Project includes exemplary natural water features (the Lower St. Croix National Scenic Riverway),
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vegetation, and geology as well as unique cultural features such as Osceola Landing (National Park
Service), the Osceola Commercial Historic District (listed on the National Register of Historic Places), and
nearby parks and trails. Within the AVE, the terrain and settlement patterns define six unique landscape
units which were determined based on assessment of aerial mapping and field visits, see Figure 4-7.
Area of Visual Effect and Visual Landscape Units.
The affected population includes motorists, recreational users, and a limited number of residents. Several
common characteristics of the AVE influence the user’s visual experience. The primary hallmark of the Riverway
is its linear form and long-distance views framed by the adjacent landform that create an immersive experience.
The bluffs also provide dramatic vistas from higher elevations looking down on the Riverway but sometime
restrict views from certain vantage points.
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Figure 4-7. Area of Visual Effect and Visual Landscape Units
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4.1.16.2 Impact Evaluation
No Build Alternative
The No Build Alternative would not result in any visual impacts with the AVE.
Preferred Alternative
Fourteen key viewsheds were identified for an assessment of impacts of the Preferred Alternative. Visual
Compatibility and Viewer Sensitivity of the preferred alignment was evaluated within each of the fourteen
viewsheds, and the resulting impacts were rated as positive, neutral, or negative. Visual Compatibility is the
measure of how the project’s visual character will fit within the project environment’s visual character. The
Visual Quality project team assessed three primary criteria for Visual Compatibility - Scale, Form, and Materials.
Viewer Sensitivity is the measure of how users may perceive the project and effects on the environment based
on anticipated exposure and awareness. This measure accounts for the unique nature of static and dynamic
viewpoints and distance. The Visual Quality project team assessed three primary criteria for Viewer Sensitivity -
Natural Harmony, Cultural Order, and Project Coherence.
Reconstruction of the bridge and highway along the same established alignment is beneficial by minimizing
impacts to the immediately adjacent natural and cultural features. Based on the selected bridge type, and
compared to the existing bridge, the overall structure depth will be reduced, and there will be fewer piers,
thereby creating more visual openness from the river. In general, the Preferred Alternative would result an
overall neutral to positive degree of impact to key viewsheds in the project area. One viewshed, the Wisconsin
shoreline north of the bridge, received a neutral/negative overall degree of impact rating because of initial
impacts to vegetation. This impact would be temporary and will be addressed through the landscaping plan
described in the Visual Quality Manual (VQM) (see Section 4.1.16.3 Mitigation). The landscaping plan combined
with the regrowth of vegetation over time would result in a net neutral visual impact along the Wisconsin
shoreline north of the bridge.
The degree of visual quality impacts of the Preferred Alternative is documented in detail in Section 4.3 of the
VIA, in APPENDIX L (Visual Impact Assessment. Table 4-11. Summary of Visual Impacts summarizes the impacts
for the fourteen key viewsheds that were studied.
Table 4-11. Summary of Visual Impacts
Viewshed Landscape
Unit
Existing
Visual
Quality
Visual
Compatibility
Viewer
Sensitivity
Overall Degree
of Impact
Osceola
Landing Boat
Launch
A (River and
Shoreline) Moderate Neutral/Negative Positive/Neutral Neutral
Osceola
Landing Picnic
Area
A (River and
Shoreline) High Positive/Neutral Neutral Neutral
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Viewshed Landscape
Unit
Existing
Visual
Quality
Visual
Compatibility
Viewer
Sensitivity
Overall Degree
of Impact
Osceola
Landing
Peninsula
A (River and
Shoreline) High Neutral Neutral Neutral
Eagle Bluff
Trail
E (Wisconsin
Upland) High Neutral Neutral Neutral
WI Shoreline
North of
Bridge
C (Tributary
Ravines) Moderate Neutral/Negative Neutral/Negative Neutral/Negative
Ladd Overlook E (Wisconsin
Upland) Low Neutral Neutral Neutral
Minnesota
Hwy 243
Approach
D (Minnesota
Upland) Moderate Neutral/Negative Neutral Neutral
Wisconsin
Hwy 243
Approach
E (Wisconsin
Upland) Moderate Neutral/Negative Neutral Neutral
St. Croix
Riverway View
Upstream
A (River and
Shoreline) High Positive/Neutral Positive/Neutral Positive/Neutral
St. Croix
Riverway View
Downstream
A (River and
Shoreline) High Positive/Neutral Positive/Neutral Positive/Neutral
Cascade Falls
Overlook
F (Downtown
Osceola) Low Positive/Neutral Neutral Neutral
Downtown
Osceola
Cascade/2nd
F (Downtown
Osceola) Moderate Neutral Neutral Neutral
Cascade Falls
Trail East
C (Tributary
Ravines) High Positive/Neutral Neutral Neutral
MN Shoreline
North of
Bridge
A (River and
Shoreline) Moderate Neutral/Negative Positive/Neutral Neutral
4.1.16.3 Mitigation
The VIA has outlined recommended mitigation measures, which are subject to change based on agency and
public review of this document. The project team identified three categories of mitigation measures to preserve
visual quality in the project area: context sensitive bridge aesthetics, vegetation restoration, and trail wayfinding
signage.
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Context Sensitive Bridge Aesthetics
Even though the planned bridge reconstruction is the central feature of the Project, it was clear from early VQAC
input that the structure should intentionally try to draw less attention to itself compared to the unique natural
setting. Primary strategies developed for minimizing the visual effect of the bridge included: right-sizing the
scale of each required component (piers, abutments, wing walls, barriers, and railings), avoiding simulated stone
concrete textures, and employing color finishes that complement the natural materials inherent to the
Riverway.
Vegetation Restoration
As part of the bridge, roadway, and trail construction, there will inevitably be limited impacts to the existing
vegetation along the edges of the corridor and nearby shorelines. With the goal of ultimately allowing the
infrastructure to blend into the landscape visually, new vegetation will soften its hardened appearance as it
matures. In addition, new vegetation can provide shade for trail users, habitat and food sources for wildlife, and
mitigate stormwater runoff and soil erosion. As part of the visual quality design process, a conceptual vegetation
plan will be developed that restores areas of the landscape impacted by construction.
Trail Wayfinding Signage
The introduction of the pedestrian and bicycle trail to the corridor creates a new way to experience the river at
this location. The connection between Osceola Landing and the Village of Osceola will invite a greater diversity
of visitors to explore the river crossing that was previously only available through a car windshield. In order to
orient and guide visitors, nodes that provide maps and recreational destination information will support positive
experiences. New trail wayfinding signage will complement existing identity and interpretive signage.
Visual Quality Manual
MnDOT and WisDOT prepared a Visual Quality Manual (VQM) for the Hwy 243 Osceola Bridge Project. The VQM
identifies design features and mitigation measures to minimize impacts and enhance visual quality with the
project. The VQM includes recommended mitigation strategies for context-sensitive bridge aesthetics,
vegetation restoration (including a landscape plan), and trail wayfinding signage. The VQM was developed with
input from the Visual Quality Advisory Committee (VQAC). The VQAC consisted of federal, state, and local
agency representatives. The VQAC met five times from June through November 2023 during the development of
the VQM. A sixth VQAC meeting was hosted in May 2024 to present final VQM recommendations and conclude
the VQAC process. Final VQM recommendations were presented at a public meeting in June 2024. The VQAC
provided feedback on visual quality goals and reviewed aesthetic options for the Hwy 243 Bridge and other
supporting design features. The VQM is available upon request by contacting the MnDOT Project Manager (see
contact information in Section 4.1.2 Proposer).
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4.1.17 Air
4.1.17.1 Stationary source emissions
Describe the type, sources, quantities and compositions of any emissions from stationary sources such as boilers
or exhaust stacks. Include any hazardous air pollutants, criteria pollutants. Discuss effects to air quality including
any sensitive receptors, human health or applicable regulatory criteria. Include a discussion of any methods used
assess the project’s effect on air quality and the results of that assessment. Identify pollution control equipment
and other measures that will be taken to avoid, minimize, or mitigate adverse effects from stationary source
emissions.
No boilers, exhaust stacks, or any other stationary source emissions are proposed as part of the Hwy 243
Osceola Bridge Project.
4.1.17.2 Vehicle emissions
Describe the effect of the project’s traffic generation on air emissions. Discuss the project’s vehicle-related
emissions effect on air quality. Identify measures (e.g. traffic operational improvements, diesel idling
minimization plan) that will be taken to minimize or mitigate vehicle-related emissions.
The following section answers the above question for highway transportation projects and air quality.
National Ambient Air Quality Standards (NAAQS)
The project conforms to the state implementation plan. This project does not require an air quality analysis
because it is exempt from Environmental Protection Agency (EPA) National Ambient Air Quality Standards
(NAAQS) transportation conformity requirements in 40 CFR 93 (Exempt Projects in 40 CFR 93.126, 40 CFR
93.127, or 40 CFR 93.128) OR because the State of MN is in full attainment as of September 24, 2022, and no
longer has any maintenance areas for purposes of air quality conformity. Therefore, no air quality analysis
related to the NAAQS has been performed.
Carbon Monoxide
Carbon monoxide (CO) is the traffic-related pollutant that has previously been of concern in the Twin Cities
Metropolitan Area. In 1999, the EPA re-designated all of Hennepin, Ramsey, Anoka, and portions of Carver,
Scott, Dakota, Washington, and Wright Counties as a maintenance area for CO. This means the area was
previously classified as a nonattainment area but has now been found to be in attainment. The 20-year
maintenance period for the Twin Cities Metropolitan Area ended in November 2019 and a CO maintenance
plan/project-level conformity analysis is no longer required.
Projects may still be subject to anti-backsliding regulations under the Clean Air Act (CAA). Due to these anti-
backsliding requirements, a project may require a CO hot spot analysis if it is a federally funded project, if
intersection volumes exceed the benchmark average annual daily traffic (AADT) of 82,300 vehicles, or if a project
includes one or more of the intersections on MnDOT’s top 10 intersection list.
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CO evaluation is performed by evaluating the worst-operating (hot-spot) intersections in the project area. The
EPA has approved a screening method to determine which intersections need hot-spot analysis. The hot-spot
screening method uses a traffic volume threshold of 82,300 entering vehicles per day. Intersections with traffic
volumes above this threshold must be evaluated using EPA-approved emission and dispersion models.
Intersections with traffic volumes below this threshold are not expected to result in CO concentrations that
exceed state or federal standards, and detailed modeling is not required.
The highest forecasted (2045) daily volume roadway is MN-95 with approximately 9,000 vehicles per day.
Because this project is in a rural area with low volume roadways, no intersection within or near the project area
approaches the threshold for hot-spot analysis, therefore, quantitative analysis for CO is not required.
Mobile Source Air Toxics
A qualitative Mobile Source Air Toxics (MSAT) analysis has been prepared for the Hwy 243 Osceola Bridge
Project. Controlling toxic air emissions became a national priority with the passage of the CAA of 1990, whereby
Congress mandated that the EPA regulate 188 air toxics, also known as hazardous air pollutants. The EPA has
assessed this expansive list in their latest rule on the Control of Hazardous Air Pollutants from Mobile Sources
(Federal Register, Vol. 72, No. 37, page 8430, February 26, 2007), and identified a group of 93 compounds
emitted from mobile sources that are listed in their Integrated Risk Information System (IRIS).53 In addition, EPA
identified nine compounds with significant contributions from mobile sources that are among the national and
regional-scale cancer risk drivers or contributors and non-cancer hazard contributors from the 2011 National Air
Toxics Assessment (NATA).54 These are 1,3-butadiene, acetaldehyde, acrolein, benzene, diesel particulate matter
(diesel PM), ethylbenzene, formaldehyde, naphthalene, and polycyclic organic matter. While FHWA considers
these the priority mobile source air toxics, the list is subject to change and may be adjusted in consideration of
future EPA rules.
Motor Vehicle Emissions Simulator (MOVES)55
According to EPA, MOVES3 is a major revision to MOVES2014 and improves upon it in many respects. MOVES3
includes new data, new emissions standards, and new functional improvements and features. It incorporates
substantial new data for emissions, fleet, and activity developed since the release of MOVES2014. These new
emissions data are for light- and heavy-duty vehicles, exhaust and evaporative emissions, and fuel effects.
MOVES3 also adds updated vehicle sales, population, age distribution, and vehicle miles traveled (VMT) data. In
the November 2020 EPA issued “MOVES3 Mobile Source Emissions Model Questions and Answers”56 where EPA
states that for on-road emissions, MOVES3 updated heavy-duty diesel and compressed natural gas emission
running rates and updated heavy-duty gasoline emission rates. They updated light-duty emission rates for
53 EPA. Integrated Risk Information System (IRIS). Accessed in June 2024 and available at https://www.epa.gov/iris/.
54 EPA. National Air Toxics Assessment (NATA). Accessed in June 2024 and available at https://www.epa.gov/national-air-toxics-
assessment.
55 FHWA. January 30, 2023. Updated Interim Guidance on Mobile Source Air Toxic (MSAT) Analysis in National Environmental Policy Act
(NEPA) Documents. Accessed March 2023 and available at
https://www.fhwa.dot.gov/ENVIRonment/air_quality/air_toxics/policy_and_guidance/msat/.
56 EPA Office of Transportation and Air Quality. EPA Releases MOVES3 Mobile Source Emissions Model: Questions and Answers. Accessed
March 2023 and available at https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1010M06.pdf.
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hydrocarbon, CO, and nitrogen oxide, and updated light-duty particulate matter rates, incorporating new data
on Gasoline Direct Injection vehicles.
Using EPA’s MOVES3 model, as shown in Figure 4-8, FHWA estimates that even if VMT increases by 31 percent
from 2020 to 2060 as forecast, a combined reduction of 76 percent in the total annual emissions for the priority
MSAT is projected for the same time period.
Diesel PM is the dominant component of MSAT emissions, making up 36 to 56 percent of all priority MSAT
pollutants by mass, depending on calendar year. Users of MOVES3 will notice some differences in emissions
compared with MOVES2014. MOVES3 is based on updated data on some emissions and pollutant processes
compared to MOVES2014, and also reflects the latest Federal emissions standards in place at the time of its
release. In addition, MOVES3 emissions forecasts are based on slightly higher VMT projections than
MOVES2014, consistent with nationwide VMT trends.
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Figure 4-8. FHWA Projected National MSAT Emission Trends 2020-260 For Vehicles Operating On Roadways Using EPA’s
MOVES3 Model
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MSAT Research
Air toxics analysis is a continuing area of research. While much work has been done to assess the overall health
risk of air toxics, many questions remain unanswered. In particular, the tools and techniques for assessing
project-specific health outcomes as a result of lifetime MSAT exposure remain limited. These limitations impede
the ability to evaluate how potential public health risks posed by MSAT exposure should be factored into
project-level decision-making within the context of NEPA.
Nonetheless, air toxics concerns continue to arise on highway projects during the NEPA process. Even as science
emerges, the public and other agencies expect FHWA to address MSAT impacts in its environmental documents.
The FHWA, EPA, the Health Effects Institute, and others have funded and conducted research studies to try to
define potential risks more clearly from MSAT emissions associated with highway projects. The FHWA will
continue to monitor the developing research in this field.
NEPA Context
NEPA requires, to the fullest extent possible, that the policies, regulations, and laws of the Federal Government
be interpreted and administered in accordance with its environmental protection goals, and that Federal
agencies use an interdisciplinary approach in planning and decision-making for any action that adversely impacts
the environment (42 U.S.C. 4332). In addition to evaluating the potential environmental effects, FHWA must also
consider the need for safe and efficient transportation in reaching a decision that is in the best overall public
interest (23 U.S.C. 109(h)). The FHWA policies and procedures for implementing NEPA are contained in
regulation at 23 CFR Part 771.
Incomplete or Unavailable Information for Project Specific MSAT Health Impacts Analysis
In FHWA’s view, information is incomplete or unavailable to credibly predict the project-specific health impacts
due to changes in MSAT emissions associated with a proposed set of highway alternatives. The outcome of such
an assessment, adverse or not, would be influenced more by the uncertainty introduced into the process
through assumption and speculation rather than any genuine insight into the actual health impacts directly
attributable to MSAT exposure associated with a proposed action.
The EPA is responsible for protecting the public health and welfare from any known or anticipated effect of an
air pollutant. They are the lead authority for administering the Clean Air Act and its amendments and have
specific statutory obligations with respect to hazardous air pollutants and MSAT. The EPA is in the continual
process of assessing human health effects, exposures, and risks posed by air pollutants. They maintain the
Integrated Risk Information System (IRIS), which is “a compilation of electronic reports on specific substances
found in the environment and their potential to cause human health effects”.57 Each report contains
assessments of non-cancerous and cancerous effects for individual compounds and quantitative estimates of
risk levels from lifetime oral and inhalation exposures with uncertainty spanning perhaps an order of magnitude.
57 EPA. Integrated Risk Information System (IRIS). Accessed in June 2024 and available at https://www.epa.gov/iris/.
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Other organizations are also active in the research and analyses of the human health effects of MSAT, including
the Health Effects Institute (HEI). Several HEI studies are summarized in FHWA’s Updated Interim Guidance on
Mobile Source Air Toxic Analysis in NEPA Documents. Among the adverse health effects linked to MSAT
compounds at high exposures are: cancer in humans in occupational settings; cancer in animals; and irritation to
the respiratory tract, including the exacerbation of asthma. Less obvious is the adverse human health effects of
MSAT compounds at current environmental concentrations 58 or in the future as vehicle emissions substantially
decrease.
The methodologies for forecasting health impacts include emissions modeling; dispersion modeling; exposure
modeling; and then final determination of health impacts – each step in the process building on the model
predictions obtained in the previous step. All are encumbered by technical shortcomings or uncertain science
that prevents a more complete differentiation of the MSAT health impacts among a set of project alternatives.
These difficulties are magnified for lifetime (i.e., 70 year) assessments, particularly because unsupportable
assumptions would have to be made regarding changes in travel patterns and vehicle technology (which affects
emissions rates) over that time frame, since such information is unavailable.
It is particularly difficult to reliably forecast 70-year lifetime MSAT concentrations and exposure near roadways;
to determine the portion of time that people are actually exposed at a specific location; and to establish the
extent attributable to a proposed action, especially given that some of the information needed is unavailable.
There are considerable uncertainties associated with the existing estimates of toxicity of the various MSAT,
because of factors such as low-dose extrapolation and translation of occupational exposure data to the general
population, a concern expressed by HEI.59 As a result, there is no national consensus on air dose-response values
assumed to protect the public health and welfare for MSAT compounds, and in particular for diesel PM. The EPA
states that with respect to diesel engine exhaust, “[t]he absence of adequate data to develop a sufficiently
confident dose-response relationship from the epidemiologic studies has prevented the estimation of inhalation
carcinogenic risk.”60
There is also the lack of a national consensus on an acceptable level of risk. The current context is the process
used by the EPA as provided by the Clean Air Act to determine whether more stringent controls are required in
order to provide an ample margin of safety to protect public health or to prevent an adverse environmental
effect for industrial sources subject to the maximum achievable control technology standards, such as benzene
emissions from refineries. The decision framework is a two-step process. The first step requires EPA to
determine an “acceptable” level of risk due to emissions from a source, which is generally no greater than
approximately 100 in a million. Additional factors are considered in the second step, the goal of which is to
58 Health Effects Institute (HEI). Special Report 16: Mobile-Source Air Toxics: A Critical Review of the Literature on Exposure and Health
Effects (2007). Accessed in June 2024 and available at https://www.healtheffects.org/publication/mobile-source-air-toxics-critical-
review-literature-exposure-and-health-effects.
59 HEI. Special Report 16, 2007. Mobile-Source Air Toxics: A Critical Review of the Literature on Exposure and Health Effects. Accessed in
June 2024 and available at https://www.healtheffects.org/publication/mobile-source-air-toxics-critical-review-literature-exposure-
and-health-effects.
60 EPA. IRIS – Diesel Engine Exhaust, Section II.C. Accessed in June 2024 and available at https://www.epa.gov/iris/.
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maximize the number of people with risks less than 1 in a million due to emissions from a source. The results of
this statutory two-step process do not guarantee that cancer risks from exposure to air toxics are less than 1 in a
million; in some cases, the residual risk determination could result in maximum individual cancer risks that are
as high as approximately 100 in a million. In a June 2008 decision, the U.S. Court of Appeals for the District of
Columbia Circuit upheld EPA’s approach to addressing risk in its two-step decision framework. Information is
incomplete or unavailable to establish that even the largest of highway projects would result in levels of risk
greater than deemed acceptable.61
Because of the limitations in the methodologies for forecasting health impacts described, any predicted
difference in health impacts between alternatives is likely to be much smaller than the uncertainties associated
with predicting the impacts. Consequently, the results of such assessments would not be useful to decision
makers, who would need to weigh this information against project benefits, such as reducing traffic congestion,
accident rates, and fatalities plus improved access for emergency response, that are better suited for
quantitative analysis.
Qualitative MSAT Analysis
A qualitative analysis provides a basis for identifying and comparing the potential differences among MSAT
emissions, if any, from the various alternatives. The qualitative assessment presented below is derived in
part from a study conducted by FHWA entitled A Methodology for Evaluating Mobile Source Air Toxic
Emissions Among Transportation Project Alternatives.62
According to FHWA guidance, a highway widening project is considered minor if the design year traffic is
predicted to be less than 140,000 – 150,000 vpd. Forecast (year 2045) annual average daily traffic (AADT)
volumes range from 7,400 to 9,000 within the project corridor. Because the design year (2045) Build
Alternative projection for average daily traffic (ADT) would not exceed 150,000 vpd within the project
corridor, a qualitative MSAT analysis, rather than a quantitative MSAT analysis, is warranted for the project.
For each alternative in the project, the amount of MSATs emitted would be proportional to the average
daily traffic volumes, or ADT, assuming that other variables such as fleet mix are the same for each
alternative. The ADT estimated for the Build Alternative is higher than that for the No Build Alternative
because the additional capacity increases the efficiency of the roadway and attracts rerouted trips from
elsewhere in the transportation network. This increase in ADT would lead to higher MSAT emissions for the
preferred action alternative along the highway corridor, along with a corresponding decrease in MSAT
emissions along the parallel routes. The emissions increase is offset somewhat by lower MSAT emission
rates due to increased speeds; according to the EPA’s MOVES3 model, emissions of all the priority MSAT
61 US Court of Appeals, District of Columbia Circuit. Natural Resource Defense Council and Louisiana Environmental Action Network v.
Environmental Protection Agency and the American Chemistry Council. Accessed in June 2024 and available at
https://www.cadc.uscourts.gov/internet/opinions.nsf/284E23FFE079CD59852578000050C9DA/$file/07-1053-1120274.pdf.
62 FHWA. A Methodology for Evaluating Mobile Source Air Toxic Emissions Among Transportation Project Alternatives. Accessed in June
2024 and available at https://www.fhwa.dot.gov/ENVIRONMENT/air_quality/air_toxics/research_and_analysis/
mobile_source_air_toxics/msatemission4.cfm.
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decrease as speed increases. The estimated ADT with the Hwy 243 Osceola Bridge Project under each of
the Build alternatives does not vary, it is expected there would be no appreciable difference in overall
MSAT emissions among the various alternatives (apart from the No Build Alternative). It is expected that
overall MSAT emissions would be marginally higher for the Hwy 243 Osceola Bridge Project though
increases will likely be countered (by some magnitude) by advances in technology and regulations.
Regardless of the alternative chosen, emissions will likely be lower than present levels in the design year
because of EPA's national control programs that are projected to reduce annual MSAT emissions by over 76
percent between 2020 and 2060 (Updated Interim Guidance on Mobile Source Air Toxic Analysis in NEPA
Documents, Federal Hwy Administration, January 18, 2023). Local conditions may differ from these
national projections in terms of fleet mix and turnover, ADT growth rates, and local control measures.
However, the magnitude of the EPA-projected reductions is so great (even after accounting for ADT
growth) that MSAT emissions in the study area are likely to be lower in the future in nearly all cases.
4.1.17.3 Dust and odors
Describe sources, characteristics, duration, quantities, and intensity of dust and odors generated during project
construction and operation. (Fugitive dust may be discussed under item 17a). Discuss the effect of dust and
odors in the vicinity of the project including nearby sensitive receptors and quality of life. Identify measures that
will be taken to minimize or mitigate the effects of dust and odors.
Dust would be generated because of construction activities associated with the project. Dust generated during
construction will be minimized through standard dust control measures such as applying water to exposed soils
and limiting the extent and duration of exposed soil conditions. Construction contractors will be required to
control dust and other airborne particulates in accordance with the contract specifications. After construction is
complete, dust levels are anticipated to be minimal because all soil surfaces exposed during construction will be
in permanent cover (i.e., paved or re-vegetated areas).
The proposed project would not generate substantial odors during construction. Potential odors would likely
include exhaust from diesel engines and fuel storage.
4.1.18 Greenhouse Gas (GHG) Emissions/Carbon Footprint
4.1.18.1 GHG Quantification
For all proposed projects, provide quantification and discussion of project GHG emissions. Include additional rows
in the tables as necessary to provide project-specific emission sources. Describe the methods used to quantify
emissions. If calculation methods are not readily available to quantify GHG emissions for a source, describe the
process used to come to that conclusion and any GHG emission sources not included in the total calculation.
Minnesota’s position near the center of North America subjects us to an exceptional variety of extreme
weather. During the course of a single year, most Minnesotans will experience both blizzards and
heatwaves, windstorms, strong thunderstorms, and heavy rains.
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The conditions, however, have changed rapidly, and an overwhelming base of scientific evidence projects
that Minnesota’s climate will see additional significant changes through the end of the 21st century.63 Over
the last several decades, the state has experienced substantial warming during winter and at night, with
increased precipitation throughout the year, often from larger and more frequent heavy rainfall events.
These changes alone have damaged buildings and infrastructure, limited recreational opportunities,
altered our growing seasons, impacted natural resources, and affected the conditions of lakes, rivers,
wetlands, and our groundwater aquifers that provide water for drinking and irrigation. The years and
decades ahead in Minnesota will bring even warmer winters and nights, and even larger rainfalls, in
addition to other climatic changes not yet experienced in the state.
In the years and decades ahead, winter warming and increased extreme rainfall will continue to be
Minnesota’s two leading symptoms of climate change. Climate models used in the 2017 National Climate
Assessment also project that Minnesota will have a greater tendency toward extreme heat, especially by
the middle of the 21st century.64 The future drought situation in Minnesota is less clear and appears to
depend on how much greenhouse gas emissions increase by mid-century.
GHG’s are gases that warm the atmosphere and surface of the planet. Human activity has been increasing
the amount of GHG’s in the atmosphere, leading to changes in the earth’s climate. The primary GHG’s are
carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), sulfur hexafluoride (SF6), and two classes of
compounds called hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs).
The most recent GHG emissions inventory from the MPCA showed that transportation overtook the
electricity generation sector to become the number one source of GHG emissions in Minnesota starting in
2016.65 This is consistent with trends in other states, and changes in both sectors and trends (electricity
decreasing, transportation increasing) are expected to continue in the future.
A GHG analysis was completed for this project using the Minnesota Infrastructure Carbon Estimator (MICE),
version 2.1.66 MnDOT evaluates GHG emissions from projects due to concerns about current and future impacts
of climate change in Minnesota. GHGs from transportation (carbon dioxide, methane and nitrous oxide)
contribute to warming of the atmosphere, which leads to effects in Minnesota that include increases in heavy
precipitation, increased flooding, and more episodes of extreme heat.
Because the project will not change traffic, operational greenhouse gas emissions are not expected to change.
Construction greenhouse gas emissions will result from production and transportation of construction materials,
and from fuel used in construction equipment. Pond construction and other drainage improvements that are
not culverts or storm sewer are not covered by the MICE tool and are therefore not included in this GHG
63 MPCA. Adapting to Climate Change in Minnesota. Accessed in February 2024 and available at
https://www.pca.state.mn.us/sites/default/files/p-gen4-07c.pdf.
64 US Global Change Research Program. Impacts, Risks, and Adaptations in the United States: Fourth National Climate Assessment,
Volume II. Accessed in February 2024 and available at https://nca2018.globalchange.gov/downloads/NCA4_Ch21_Midwest_Full.pdf.
65 MnDOT. Sustainability and Public Health. Accessed in February 2024 and available at https://www.dot.state.mn.us/sustainability/
66 MnDOT. Minnesota Infrastructure Carbon Estimator Tool. Accessed in December 2023 and available at
http://www.dot.state.mn.us/project-development/subject-guidance/greenhouse-gas-analysis/process.html.
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analysis. Table 4-12. MnDOT Greenhouse Gas Analysis Summary summarizes the planning-level greenhouse gas
emissions which were calculated using the MICE tool.
Table 4-12. MnDOT Greenhouse Gas Analysis Summary
Construction CO2e Emissions (Total over Construction Period) CO2e, Metric Tons (total)
Build Alternative 1,519
4.1.18.2 GHG Assessment
Describe any mitigation considered to reduce the project’s GHG emissions.
MnDOT has identified several practices that can help reduce emissions from projects. These practices directly
reduce emissions through decreased fuel use, or indirectly through materials reuse (i.e. less processing and
transport of new materials). The project is still under design, so the emissions reductions (per mile) for all of
these practices has not yet been determined.
Describe and quantify reductions from selected mitigation, if proposed to reduce the project’s GHG emissions.
Explain why the selected mitigation was preferred.
Two standard mitigation practices applied to all projects include the switch from diesel to soybean-based fuel
(to reflect state biofuel requirements) and alternative snow removal strategies (snow fencing, wing plows).
Additional mitigation practices that are expected for this specific project are existing roadway concrete and
bituminous pavement recycling. Total GHG emissions reductions from these practices are estimated to be
approximately 40 metric tons of CO2e. This includes reductions in materials, transportation, construction, and
maintenance.
Quantify the proposed projects predicted net lifetime GHG emissions (total tons/#of years) and how those
predicted emissions may affect achievement of the Minnesota Next Generation Energy Act goals and/or other
more stringent state or local GHG reduction goals.
Assuming a lifetime of 20 years for the project, the total net lifetime GHG emissions are 1,519 metric tons CO2e
for the build alternative construction emissions, plus 15 metric tons per year associated with land use changes,
which equals 1,819 total metric tons CO2e.
MnDOT was the first state agency to apply the Next Generation Energy Act GHG reduction goals to all agency
operations, including fleet fuel use and electricity. Minnesota was also the first state in the country to create
GHG reduction goals for the state highway construction program.67 While this project may not directly
contribute to the achievement of the Minnesota Next Generation Energy Act, the project will eliminate GHG
emissions associated with transportation inefficiencies, mobility, and crashes. As mentioned previously, MSAT
emissions are also projected to decrease over time due to increased speeds in the project area and from the
67 MnDOT. Sustainability and Public Health. Accessed in February 2024 and available at https://www.dot.state.mn.us/sustainability/
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EPA’s national control programs which are projected to reduce annual MSAT emissions by over 90 percent
between 2010 and 2050 (Updated Interim Guidance on Mobile Source Air Toxic Analysis in NEPA Documents,
Federal Hwy Administration, October 12, 2016). MnDOT is also dedicated to other state legislation. Executive
Order 19-27 requires MnDOT to report and make progress on six sustainability goals, one of which is reducing
GHG emissions. In 2022, MnDOT formulated seven actions to increase understanding of sustainable pavement
opportunities, all of which have potential to reduce GHG emissions.68
While agencies will need to search for a multitude of ways to reduce emissions, the net effect of the effort to
meet the Minnesota Next Generation Energy Act goals may be increased innovation, collaborative
opportunities, and public/private partnerships. Quantifying emissions by activity is the first step in meeting
these goals.
Summary of GHG Discussion
This section summarizes the GHG emissions associated with construction of the proposed project, and vehicle
traffic associated with the project. It does not include an assessment of the potential climate effects of those
emissions. In the case of GHGs and climate change, climate is driven by global cumulative changes of GHG
concentrations in the atmosphere; the changes in emissions from one individual project are simply too small to
justify calculation of resulting changes in temperature, sea level, precipitation, and other significant cumulative
climate effects. However, estimation of emissions is still useful to the public and decisionmakers so that they can
understand whether projects are contributing to progress in mitigating climate change.
Assessing GHG emissions from transportation projects is one of several strategies that MnDOT is pursuing to
address the issue of climate change. Other strategies that MnDOT is pursuing include intermodal transportation,
electric vehicle incentives and infrastructure, clean vehicle standards, and alternative fuels. The agency is also
developing a process for evaluating flood risk to MnDOT bridges, large culverts, and pipes. Studying the
performance of infrastructure under predicted extreme events will help MnDOT gain knowledge and better
assess the impacts of climate changes to plan, design, build, and maintain assets for resilience. More
information regarding MnDOT’s efforts to address climate change can be found at Sustainability at
https://www.dot.state.mn.us/sustainability/
4.1.19 Noise
Describe sources, characteristics, duration, quantities, and intensity of noise generated during project
construction and operation. Discuss the effect of noise in the vicinity of the project including 1) existing noise
levels/sources in the area, 2) nearby sensitive receptors, 3) conformance to state noise standards, and 4) quality
of life. Identify measures that will be taken to minimize or mitigate the effects of noise.
Construction activities associated with the proposed project would result in increased noise levels relative to
existing conditions. These impacts would primarily be associated with construction equipment and pile driving.
Table 4-13 shows peak noise levels monitored at 50 feet from several types of construction equipment. This
68 MnDOT. MnDOT 2022 Sustainability Report. Accessed in February 2024 and available at https://www.dot.state.mn.us/sustainability/
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equipment is usually used during site grading, site preparation, and roadway construction which is usually the
loudest phase of the roadway construction process.
Source: United States EPA and FHWA.
Elevated noise levels are to a degree unavoidable for this type of project. MnDOT will require that construction
equipment be properly muffled and in proper working order. While MnDOT and its contractor(s) are exempt
from local noise ordinances, it is the practice to require that the contractor(s) comply with applicable local noise
restrictions to the extent possible. Advance notice will be provided to affected communities for any abnormally
loud construction activities. However, construction will be limited to daytime hours as much as possible. This
project is anticipated to be under construction for two construction seasons.
Any associated high-impact equipment noise such as pile driving, pavement sawing, or jack hammering will be
unavoidable with construction of the Preferred Alternative. Pile driving noise is associated with any sheet piling
necessary for bridge construction and any retaining wall construction. The use of pile drivers, pavement sawing,
and jack-hammering equipment will be prohibited during nighttime hours.
Elevated noise levels would be temporary (i.e., limited to the construction of phase of the project) and
minimized to the extent practicable as described above. The proposed project would not contribute to traffic
growth, does not include additional highway capacity, and maintains the Hwy 243 Bridge along its existing
alignment. The proposed project would not permanently change traffic noise levels compared to the No Build
Alternative.
Noise is defined as any unwanted sound. Sound travels in a wave motion and is measured as a sound pressure
level. This sound pressure level is commonly measured in decibels. Decibels (dB) represent the logarithm of the
ratio of a sound energy relative to a reference sound energy. For highway traffic noise, an adjustment, or
weighting, of the high-and low-pitched sound is made to approximate the way that an average person hears
sound. The adjusted sound levels are stated in units of “A-weighted decibels” (dBA). A sound increase of 3 dBA is
barely noticeable by the human ear, a 5 dBA increase is clearly noticeable, and a 10 dBA increase is heard as
twice as loud. For example, if the sound energy is doubled (i.e., the amount of traffic doubles), there is a 3 dBA
Table 4-13. Typical Construction Equipment Noise Levels at 50 Feet
Equipment Type Manufacturers Sampled Total Number of
Models in Sample
Peak Noise
Level (dBA)
Range
Peak Noise
Level (dBA)
Average
Backhoes 5 6 74-92 83
Front Loaders 5 30 75-96 85
Dozers 8 41 65-95 85
Graders 3 15 72-92 84
Scrapers 2 27 76-98 87
Pile Drivers N/A N/A 95-105 101
4.1.19.1 Existing Noise Levels/Sources in the Area
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increase in noise, which is just barely noticeable to most people. On the other hand, if traffic increases by a
factor of ten times, the resulting sound level will increase by about 10 dBA and be heard to be twice as loud.69
Existing noise sources in the project area include traffic noise from Hwy 243, as well as traffic entering and
exiting Osceola Landing in Minnesota. Other noise sources include operations at Osceola Landing and activities
on the St. Croix River, such as motorized boats. Ambient noise levels are anticipated to be low due to the rural
nature of the project and the low volumes of vehicles on Hwy 243. There is also a railway just south of the
project area in Wisconsin, which intermittently contributes existing noise levels in the area.
4.1.19.2 Nearby Sensitive Noise Receptors
Because the project is within the St. Croix National Scenic Riverway, much of the project consists of
undeveloped MnDNR or NPS land. Noise sensitive receptors within the immediate vicinity of the project include
Osceola Landing in Minnesota and two recreational trails that exist beneath the Hwy 243 Bridge on the
Wisconsin side of the river. These trails are Cascade Falls Trail and Eagle Bluff Trail.
Other noise sensitive receptors are beyond the project area. Several noise sensitive receptors reside in the
Village of Osceola, Wisconsin, which begin approximately 125 feet from the eastern project limit. A residential
property resides approximately 1,500 feet west of the western project limit.
4.1.19.3 Conformance to the State Noise Standards
The Minnesota state noise standards are located in Minnesota Rules Chapter 7030. The MPCA is the state
agency responsible for enforcing state noise rules. In 2016, the Commissioners of the MPCA and MnDOT agreed
that the traffic noise regulations and mitigation requirements from the FHWA are sufficient to determine
reasonable mitigation measures for highway noise. By this agreement, existing and newly constructed segments
of highway projects under MnDOT’s jurisdiction are statutorily exempt from the Minnesota State Noise Standard
(Minnesota Rules Chapter 7030) if the project applies the FHWA traffic noise requirements. As a result, the
traffic noise analysis conducted for the project has followed FHWA criteria and regulations only. This project is
not required to address Minnesota Rules Chapter 7030.
Traffic noise impacts in Minnesota are evaluated by measuring and/or modeling the traffic noise levels that are
exceeded 10 percent and 50 percent of the time during the hours of the day and/or night that have the loudest
traffic scenario. These numbers are identified as the L10 and L50 levels, respectively. The L10 value is the noise
level that is exceeded for a total of 10 percent, or 6 minutes, of an hour. The L50 value is the noise level that is
exceeded for a total of 50 percent, or 30 minutes, of an hour.
Wisconsin requirements for traffic noise follow the FHWA’s traffic noise regulation in 23 Code of Federal
Regulations (CFR) Part 772 (Procedures for Abatement of Hwy Traffic Noise and Construction Noise).
69 MnDOT. Hwy Traffic Noise and Noise Barriers. Accessed in February 2024 and available at
https://www.dot.state.mn.us/environment/noise/pdf/Noise%20BrochureV4_FINAL_no%20contact%20for%20web.pdf.
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The Hwy 243 Osceola Bridge Project is not a Type I project and is not anticipated to contribute to traffic growth
or any other permanent changes to traffic noise, therefore a detailed traffic noise analysis was not completed.
Documentation of reasoning for this determination is provided below. This documentation was discussed and
agreed upon with MnDOT’s Noise and Air Quality Program Supervisor.
• Horizontal alignment. The centerline of the proposed bridge/roadway shifts by approximately 11-12
feet to the south compared to the existing bridge. The north edge of the proposed bridge matches the
north edge of the existing bridge. The proposed bridge includes a 12-foot wide shared-use path on the
north side of the bridge. The travel lanes are shifted to the south by 11-12 feet to accommodate the
shared-use path.
o The nearest noise sensitive receptor on the north side of the bridge is a home along the WI
shoreline. The bridge isn’t moving closer to this residence and does not change the line of sight
to this residence.
o The nearest noise sensitive receptor on the south side of the bridge on the MN side is Osceola
Landing. The 11-12 foot shift in the travel lanes does not halve the distance.
o The nearest noise sensitive receptor on the south side of the bridge on the WI side is a public
access/dock (operated by Village of Osceola). The 11-12 foot shift in travel lanes does not halve
the distance. A trail is perpendicular to the bridge and crosses underneath along the WI
shoreline. The proposed bridge does not vertically or horizontally halve the distance to this trail.
• Vertical alignment. The elevation of the existing bridge at the WI abutment is 741.4 feet (from original
plans). The elevation of the proposed bridge at the WI abutment is 741.6 feet. There is no substantial
change in vertical alignment of the bridge.
• Lanes. No additional thru lanes or capacity is being added to the bridge or the surrounding roadway
network.
4.1.19.4 Quality of Life
Quality of life is not anticipated to be permanently impacted by the proposed project.
4.1.20 Transportation
Describe traffic-related aspects of project construction and operation. Include: 1) existing and proposed
additional parking spaces, 2) estimated total average daily traffic generated, 3) estimated maximum peak hour
traffic generated and time of occurrence, 4) indicate source of trip generation rates used in the estimates, and 5)
availability of transit and/or other alternative transportation modes.
Discuss the effect on traffic congestion on affected roads and describe any traffic improvements necessary. The
analysis must discuss the project’s impact on the regional transportation system. If the peak hour traffic
generated exceeds 250 vehicles or the total daily trips exceeds 2,500, a traffic impact study must be prepared as
part of the EAW. Use the format and procedures described in the Minnesota Department of Transportation’s
Access Management Manual, Chapter 5 (available at:
http://www.dot.state.mn.us/accessmanagement/resources.html) or a similar local guidance
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This project is a transportation improvement project that has a purpose to maintain a highway connection over
the St. Croix River in the Hwy 243 corridor. The project does not add highway capacity (i.e., does not add lanes
to Hwy 243) and does not change traffic volumes compared to the No Build Alternative. The project does not
affect traffic congestion on Hwy 243 and would not generate additional traffic to and/or from the project area.
Therefore, a traffic impact study was not prepared as part of this EA/EAW.
The Hwy 243 Bridge would be fully closed to traffic during construction. US Hwy 8 is the recommended detour
route for the Hwy 243 Bridge closure that will occur during construction of the project. A Transportation
Management Plan (TMP) for construction is being developed for the project. The TMP included an assessment of
existing and proposed peak queueing conditions at the US Hwy 8 and MN-95 intersection in Taylors Falls, MN.
For the purposes of this analysis, the existing condition represents when the Hwy 243 Bridge is open and
proposed conditions represent the Hwy 243 Bridge closure. Traffic operations at US Hwy 8 and MN-95 during
construction, including metrics such as traffic delays, queuing, and LOS. LOS is a qualitative measure of the
effect of traffic flow factors, such as speed and travel time, interruption, freedom to maneuver, driver comfort
and convenience, and indirectly, safety and operating costs.70
Several scenarios were evaluated to assess traffic delay and LOS at US Hwy 8 and MN-95 during the proposed
Hwy 243 Bridge closure. These three scenarios included: 1) existing lane configuration on the US Hwy 8 bridge
(two westbound lanes, one eastbound lane) with the Hwy 243 Bridge open; 2) re-striping the US Hwy 8 bridge to
include one westbound lane and two eastbound lanes with the Hwy 243 Bridge closed; and 3) re-striping the US
Hwy 8 bridge to four lanes (two lanes in each direction) with the Hwy 243 Bridge closed. Traffic operations were
modeled for Friday, Saturday, and Sunday peak hours. Figures A4-1 through A4-9 in APPENDIX A (Figures)
illustrate the findings of this traffic operations analysis. The four-lane configuration on the US Hwy 8 bridge
would result in the least magnitude of delay and shortest traffic queues at the US Hwy 8/MN-95 intersection
during Hwy 243 Bridge closure.
The US Hwy 8 bridge will be temporarily re-striped to four lanes to accommodate higher volumes of traffic
during the Hwy 243 Bridge closure. Figure A5 in APPENDIX A (Figures) shows the existing and proposed lane
configuration for the US Hwy 8 bridge during construction of this project.
The Hwy 243 approach roadways in Minnesota and Wisconsin would be closed to traffic during construction.
Hwy 243 from MN-95 to the Osceola Landing entrance in Minnesota would remain open during construction for
public access to the Osceola Landing site. Hwy 243 from the St. Croix River up the Wisconsin bluff to WIS-35
would be closed to traffic. The existing four-way stop at Hwy 243 and WIS-35 would be temporarily converted to
a two-way stop condition during construction.
MnDOT and WisDOT met with emergency service providers on August 20, 2024 to discuss the project and
closure of the Hwy 243 Bridge during construction. Osceola Fire (Wisconsin) currently responds to incidents on
the St. Croix River and at Osceola Landing. Osceola Fire uses Osceola Landing for boat access to the river. Shafer
Franconia Fire & Rescue (Minnesota) will act as the primary responder to Osceola Landing during construction.
70 MnDOT. Information and resources. Accessed in April 2024 and available at https://www.dot.state.mn.us/information/glossary.html.
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MnDOT and WisDOT will continue to coordinate with emergency service providers as part of the TMP
development.
Any construction traffic mitigation measures implemented for this project would be temporary in nature;
therefore, these measures do not need to be analyzed for traffic noise impacts as part of the Hwy 243 Osceola
Bridge Project. “Temporary” means that the facilities off the mainline construction will be returned to their pre-
project state no later than 90 days after the contractor is demobilized from the mainline construction project. If
weather conditions make it impossible to return temporary improvements to the original condition within the
90-day period, then the temporary work will be returned to pre-project conditions within 90 days of April 15 of
the next calendar year or when season striping operations begin, whichever comes first.
4.1.20.1 Parking
Additional parking spaces are not proposed; however, the project will reconstruct existing parking areas within
the Minnesota wayside rest (north side of Hwy 243) and within Osceola Landing (south of Hwy 243). The
wayside rest area would be relocated to the west with the project and is estimated to be approximately 10
parking spaces or less. The Osceola Landing north parking lot would be used for staging and construction of the
Hwy 243 Bridge replacement. The Osceola Landing north parking lot would be reconstructed to be outside of
existing MnDOT right of way and a design coordinated with the National Park Service.
4.1.20.2 Total average daily traffic generated
The proposed project would not generate any additional traffic to the area. However, existing roadways
experience daily traffic and are anticipated to experience gradual traffic growth between now and 2040. Table
4-14. Daily Traffic Volumes (Existing and Forecasted) tabulates existing and forecasted daily traffic volumes for
existing roadways within or near the project area.
Table 4-14. Daily Traffic Volumes (Existing and Forecasted)
Roadway/Location Existing Volume (2022) 2040 No Build
Alternative
2040 Build Alternative
Hwy 243 Bridge 5,690 7,400 7,400
MN-95 6,650 9,100 9,100
WIS-35 9,500 13,000 13,000
Note: Existing AADT volumes for Minnesota roadways were retrieved from MnDOT’s Traffic Mapping Application. Traffic volumes for
WIS-35 are north of the Hwy 243 intersection in the Village of Osceola.
4.1.20.3 Estimated Maximum Peak Hour Traffic Generated and Time of Occurrence
Traffic volumes on the Hwy 243 Bridge have a distinct directionality during the peak hours of the day. Traffic
flow in the morning is predominately destined westbound whereas traffic flow in the afternoon is
predominately destined eastbound. Table 4-15 tabulates forecast peak hour traffic volumes on the Hwy 243
Bridge.
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Table 4-15. Hwy 243 Peak Hour Traffic Volumes
Peak Eastbound Westbound Total (both directions)
AM 300 440 740
PM 490 370 860
Note: The AM Peak generally represents the 7:00 am to 8:00 am hour and the PM Peak generally represents the 4:00 pm to 5:00 pm
hour.
4.1.20.4 Source of Trip Generation Rates used in Estimates
The Met Council’s Activity Based Model (ABM) is the travel demand forecasting model for the Twin Cities
Metropolitan Area, and includes Polk, St. Croix, and Pierce counties in Wisconsin. The ABM was first used to
develop traffic forecasts for the Hwy 243 Osceola Bridge Project to predict travel patterns at the regional level.
Travel movements for the project study area were extracted from the ABM and used to develop traffic forecasts
at the project level.
4.1.20.5 Availability of Transit and/or other alternative transportation modes
There are no existing transit facilities or services within the project area in either the Village of Osceola or
Franconia Township and no transit is planned. Polk County offers non-emergency medical transport to senior
citizens or people with disabilities to meet their healthcare needs 71 but this is not considered public transit.
Arrowhead Transit services parts of Chisago County, but not within the project area. Alternative transportation
modes like medical transport and school bus routes would be impacted by the Hwy 243 Bridge closure and
would be routed to the US Hwy 8 detour to the north of the project area. Coordination with transport service
and school bus operators will occur prior to construction and closure of the Hwy 243 Bridge.
4.1.21 Cumulative Potential Effects
(Preparers can leave this item blank if cumulative potential effects are addressed under the applicable EAW
Items)
4.1.21.1 Describe the geographic scales and timeframes of the project related environmental effects
that could combine with other environmental effects resulting in cumulative potential effects.
Minnesota Rules, Part 4410.0200, subpart 11a and 40 CFR Part 1508.7 define cumulative impacts as impacts on
the environment that result from the incremental impact of the action when added to other past, present, and
reasonably foreseeable future actions regardless of what agency or persons undertake such actions. The
objective of cumulative potential effects analysis is to identify impacts that may be minimal, and therefore,
neither significant nor adverse when examined within the context of the proposed action, but that may
accumulate and become significant and adverse when combined with other actions.
71 Polk County, Wisconsin. Transportation in Polk County. Accessed in February 2024 and available at
https://www.polkcountywi.gov/residents/transportation_in_polk_county.php.
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The geographic areas considered for cumulative potential effects are those areas directly adjacent to or near the
Hwy 243 Osceola Bridge Project, as well as areas near the detour route for the bridge closure. Past actions in the
project vicinity include decades of agricultural, residential, institutional, industrial, and commercial development
and transportation infrastructure improvements. All the past actions have resulted in the current built
environment surrounding the Hwy 243 Bridge, which is generally undeveloped near the bridge but urban
development to the east in the Village of Osceola, Wisconsin. The current limit of comprehensive planning
efforts for the project area is the year 2030. These efforts can be used as the basis for future cumulative impacts
from projects planned within this time frame.
Project related environmental effects that could combine with other environmental effects resulting in
cumulative potential effects and proposed mitigation are tabulated in Table 4-16. Project Related Environmental
Effects and Geographic Extent.
Table 4-16. Project Related Environmental Effects and Geographic Extent
Reference Topic Environmental
Effects
Geographic
Extent
Mitigation Plan
Section
4.1.11.2 (EAW
Item 11)
Soils and
Topography
(Erosion and
Sedimentation
Control)
Disturbed
ground/soils
during project
construction.
Throughout the
project area
NPDES and WPDES permits and
SWPPP would be developed
prior to construction.
Section 4.1.12
(EAW Item 12)
Water Resources Increase in
impervious
surface of 1.1
acres across the
entire project
(MN and WI
areas combined).
Impacts to
wetland basins:
0.35 acres
Impacts to
aquatic
resources: 0.88
acres
Throughout the
project area
Water resources impacts have
been minimized to the extent
practicable with sequencing
methodology throughout
project development.
Compensatory mitigation will
be completed for unavoidable
wetland impacts. Cofferdams
and barges will be used during
construction to reduce river
bottom and sedimentation
impacts within the St. Croix
River. River bottom restoration
will be completed once the
causeways are removed.
Section 4.1.13
(EAW Item 13)
Contaminated
and Regulated
Wastes
Twenty-five (25)
contaminated
sites were
identified within
or near the
Throughout the
project area
Hazardous materials and
regulated waste encountered
as part of the proposed and
future actions would be
handled and disposed of
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Reference Topic Environmental
Effects
Geographic
Extent
Mitigation Plan
project area. according to applicable state
and federal rules and
regulations.
Section 4.1.14
(EAW Item 14)
Fish, Wildlife, and
Plant
Communities
Aquatic habitats
and communities
are anticipated to
be impacted by
the project
during the
entirety of
construction.
Throughout the
project area
Addressed via permanent
stormwater management,
implementation of a SWPPP,
date restriction on construction
activities to minimize light,
noise, wildlife habitat impact,
revegetation of disturbed soil
would include native seed
mixes. Conservation measures
will be implemented to
minimize impacts to bats. Two
wildlife crossings will be
constructed in Minnesota, west
of Osceola Landing. Rip rap
along the St. Croix will be
constructed to avoid small
openings (for small wildlife
protections). Wildlife fencing is
planned near the proposed
Minnesota stormwater pond
near Osceola Landing. Mussels
will be relocated from the
project area to an approved
relocation site. A Mussel
Relocation Plan will be
approved by USFWS prior to
the start of construction. Post-
relocation monitoring will be
completed per the Mussel
Relocation Plan. The earthen
causeways include a 90-foot
center opening and two
additional 10-foot-wide
openings for fish passage
during construction.
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Reference Topic Environmental
Effects
Geographic
Extent
Mitigation Plan
Section 4.1.18
(EAW Item 18)
GHG
Emissions/Carbon
Footprint
Greenhouse gas
distribution
changes due to
detour route
during
construction.
Throughout the
project area and
along the project
detour route
In the long-term, the Build
Alternative is not anticipated to
affect VMT relative to the No
Build Alternative.
Section 4.1.19
(EAW Item 19)
Construction
Noise
Areas adjacent to
or near the
project would
experience noise
from equipment
and activities
during
construction, see
Section 4.1.19.
Throughout the
project area
Advance notice will be provided
to affected communities for
any abnormally loud
construction activities. Any
associated high-impact
equipment noise such as pile
driving, pavement sawing, or
jack hammering will be
unavoidable with construction
of the Preferred Alternative.
The use of pile drivers,
pavement sawing and jack-
hammering equipment will be
prohibited during nighttime
hours.
Section 4.1.20
(EAW Item 20)
Transportation Construction of
the bridge would
require the
closure of the
Hwy 243Bridge
for multiple years
and as such there
would be long-
term traffic
diversions that
may result in a
temporary
increase in
vehicle miles
traveled.
Throughout the
project area and
along the project
detour route
Traffic management planning
would be conducted prior to
construction. Public outreach
would continue prior to and
throughout construction to
provide advance notice of
transportation impacts.
Section 4.2.7
(Additional
Federal Issues)
Section 4(f)
Resources
De Minimis
impacts to the St.
Croix National
Throughout the
project area
Several protection and
mitigation measures are
proposed for the Riverway,
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Reference Topic Environmental
Effects
Geographic
Extent
Mitigation Plan
Scenic Riverway
and temporary
occupancy of the
State Water Trail
and the Cascade
Falls Trail.
Section 4(f)
documentation
can be found in
APPENDIX N
(Section 4(f)
Involvement – De
Minimis
Determination
and Temporary
Occupancies).
based on each outstandingly
remarkable value that is
anticipated to be impacted.
River navigation within the
Riverway and the State Water
Trail will be periodically opened
to recreational users
throughout construction, with a
focus on peak visitation times.
A detour is proposed for the
temporary closure of the
Cascade Falls Trails along the
Wisconsin shoreline. Other
protection and mitigation
measures are described in
detail in Table 2 of the De
Minimis Determination Notice
of Intent Request located in
APPENDIX N (Section 4(f)
Involvement – De Minimis
Determination and Temporary
Occupancies).
4.1.21.2 Describe any reasonably foreseeable future projects (for which a basis of expectation has
been laid) that may interact with environmental effects of the proposed project within the
geographic scales and timeframes identified above.
MnDOT’s 2024-2033 Capital Hwy Investment Plan (CHIP), MnDOT’s 2024-2027 State Transportation
Improvement Program (STIP), Chisago County 2016-2026 Comprehensive Plan, Chisago County 2024-2027
Capital Improvement Plan, Village of Osceola 2009-2029 Comprehensive Plan, and WisDOT’s Northwest Region
Hwy Projects and Studies website were reviewed to identify reasonably foreseeable future projects near the
Hwy 243 Osceola Bridge Project area and the US Hwy 8 detour route. As noted in the BA, potential cumulative
effects of this project could include the effects of future non-federal state, local, or private activities that are
reasonably certain to occur adjacent to or within the project area. Projects for which no timeframe is
determined are routine roadway and bridge maintenance (e.g., snow and ice control), and routine bridge
inspections. The following programmed projects were identified, see Table 4-17.
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Table 4-17. Reasonably Foreseeable Projects Near the Project Area and Detour Route
Timeframe Agency Location Project Description
2026 MnDOT Hwy 243 and MN-95 Construct roundabout
2026 MnDOT MN-95 and Pleasant
Valley Rd
Construct dedicated right and left turn lanes, drainage work,
install lighting
2028-2029 NPS Osceola Landing north
parking lot
Osceola Landing Phase 2 Improvements - reconstruction of
the northern parking lot and river access points/boat
launches
2028-2029 WisDOT US Hwy 8 - MN/WI
State Line to Glacier
Rd
Mill and overlay existing pavement and other incidentals
necessary
2030 MnDOT US Hwy 8 and the St.
Croix River
Replace US Hwy 8 bridge over the St. Croix River
2033 MnDOT Hwy 36 and the St.
Croix River
Resurface Hwy 36 bridge over the St. Croix River
4.1.21.3 Discuss the nature of the cumulative potential effects and summarize any other available
information relevant to determining whether there is potential for significant environmental effects
due to these cumulative effects.
Environmental effects that would result from the proposed project are summarized in Table 4-16. Project
Related Environmental Effects and Geographic Extent. Each of the reasonably foreseeable projects near the
project or detour route, shown in Table 4-17, could influence the following environmental topics:
• Fish, Wildlife, Plant Communities, and Sensitive Ecological Resources (Rare Features): foreseeable
future actions are anticipated to be on or within existing facilities and would not expand capacity or
substantially change existing alignment, thus impacts to wildlife habits are anticipated to be limited.
Foreseeable future projects are expected to occur within previously disturbed areas. Foreseeable future
projects that are granted federal funding will undergo separate Section 7 review and/or consultation, if
needed, which will result in specific project-level conservation measures to avoid, minimize, and
mitigate impacts on these natural resources. No other foreseeable future project involves in-water work
within the St. Croix River. The most significant project which would affect fish, wildlife, plant
communities, and rare features is the Hwy 243 Osceola Bridge Project. The Preferred Alternative for this
project results in the least amount of in-water impacts and least number of impacts to the surrounding
natural environment compared to all other alternatives considered. Formal consultation with the
USFWS, as well as direct coordination with the MnDNR and WisDNR, is occurring with the proposed
project. A multitude of conservation measures are proposed with the Hwy 243 Osceola Bridge project
and will be implemented during construction with an Environmental Management Plan (APPENDIX F
(Environmental Management Plan)).
• Noise: future construction projects that occur simultaneously with the Hwy 243 Osceola Bridge Project
may contribute to construction noise. This could potentially lead to additional localized increases in
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noise levels. All projects, including the Hwy 243 Osceola Bridge Project and future projects, will be
required to comply with applicable local and state noise requirements.
• Transportation: The cumulative impact of the foreseeable future projects would result in improved
traffic conditions and an overall better experience for transportation users. Future development is taken
into consideration as part of the Traffic Management Plan and other traffic analysis completed for the
Hwy 243 Osceola Bridge Project. Construction of the proposed project would occur from late 2026 to
the summer of 2029 and would require a detour north to US Hwy 8 to cross the St. Croix River. The
Preferred Alternative of this project results in the shortest duration of overall construction compared to
other build alternatives that were evaluated, therefore minimizing traffic impacts to the extent
practicable. MnDOT and WisDOT would coordinate with local agencies to ensure the detour route and
adjacent roads would not conflict vehicle, transit, or pedestrian traffic with future construction projects.
• Section 4(f) Resources: impacts to the St. Croix National Scenic Riverway are not anticipated to be
permanent or substantial, due to the high-level of communication and coordination with NPS, the
Official with Jurisdiction (OWJ) over the Riverway, as well as the inclusion of a robust set of protection
and mitigation measures with the Hwy 243 Osceola Bridge Project. Coordination of this project’s effects
on the St. Croix National Scenic Riverway began in 2021, are ongoing, and will continue through
construction. The proposed project will restore Section 4(f) resources to a condition at least as good as
prior to construction, if not a better condition compared to existing. The Osceola Landing Phase 2
Improvements will be constructed by MnDOT and WisDOT in coordination with NPS following
completion of bridge construction. Therefore, substantial cumulative effects are not anticipated. See
APPENDIX N (Section 4(f) Involvement – De Minimis Determination and Temporary Occupancies) for the
De Minimis Determination and documentation for the St. Croix National Scenic Riverway.
Based on the information known through the development of this EA/EAW, there is little potential for
substantial cumulative impacts to the resources directly or indirectly impacted by the project. Existing regulatory
controls and mitigation measures proposed through the environmental review process will minimize impacts (as
much as practicable) and restore the resources, therefore, no cumulative potential effects are anticipated to
resources affected by this project.
4.1.22 Other Potential Environmental Effects
If the project may cause any additional environmental effects not addressed by Sections 4.1.1 to 4.1.21, describe
the effects here, discuss the how the environment will be affected, and identify measures that will be taken to
minimize and mitigate these effects.
Section 4.2 Additional Federal Issues discusses other potential environmental effects. (APPENDIX F
(Environmental Management Plan) includes the Environmental Management Plan (i.e., conservation measures,
mitigation commitments, and enhancements) for the Hwy 243 Osceola Bridge Project. The project will be
reviewed and coordinated with WisDNR through the WisDOT/WisDNR Cooperative Agreement process.
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4.1.23 RGU CERTIFICATION
(The Environmental Quality Board will only accept SIGNED Environmental Assessment Worksheets for public
notice in the EQB Monitor.)
I hereby certify that:
The information contained in this document is accurate and complete to the best of my knowledge.
The EAW describes the complete project; there are no other projects, stages or components other than those
described in this document, which are related to the project as connected actions or phased actions, as defined
at Minnesota Rules, parts 4410.0200, subparts 9c and 60, respectively.
Copies of this EAW are being sent to the entire EQB distribution list.
Signature Date______________
Assistant Engineering Services Division Director
Title
Lynn Clarkowski Digitally signed by Lynn
Clarkowski
Date: 2024.11.15 15:35:07 -06'00'
Environmental Assessment Worksheet was prepared by the staff of the Environmental Quality Board at the
Minnesota Department of Administration, Office of Geographic and Demographic Analysis. For additional
information, worksheets or for EAW Guidelines, contact: Environmental Quality Board, 658 Cedar St., St. Paul,
MN 55155, 651-201-2492, or http://www.eqb.state.mn.us
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4.2 Additional Federal Issues
Discussed below are the federal issues not discussed in the EAW.
4.2.1 Social Impacts
The following social impacts were evaluated for the Hwy 243 Osceola Bridge Project:
• Travel patterns and access
• Accessibility
• Community facilities and public services
• Community and neighborhood cohesion
• Transportation sensitive communities
4.2.1.1 Travel Patterns and Access
Existing Hwy 243 intersections and MN-95 and WIS-35 will not change with the project. Access to NPS’s Osceola
Landing will not change and will be maintained with the project. However, Hwy 243 between Minnesota and
Wisconsin will be temporarily closed during construction. Hwy 243 is expected to be closed for two years (24
months). The primary detour route during project construction will use MN-95 and WIS-35 to the US Hwy 8
Bridge over the St. Croix River between Taylors Falls, Minnesota and St. Croix Falls, Wisconsin. Figure 2-4 in
Section 2 illustrates the anticipated primary detour route. This detour route would increase travel times and
distances between Franconia Township and Village of Osceola. It is anticipated that trips destined to/from the
Village of Osceola and the Twin Cities Metropolitan Area will likely divert to the MN-36/WI-64 crossing at Oak
Park Heights, Minnesota and Town of St. Joseph, Wisconsin.
Students on the Minnesota side of the St. Croix River attend school in the Village of Osceola, Wisconsin. School
buses will cross the St. Croix River at Hwy 243 to access Village of Osceola schools. Closure of Hwy 243 during
project construction will increase travel times and distances for students in Minnesota to access schools in
Wisconsin. School bus trips using the detour route to US Hwy 8 in Taylors Falls/St. Croix Falls will need to
account for additional travel time at the start and end of the school day to reach their destinations.
There are no transit routes that use the Hwy 243 Bridge that would be temporarily or permanently impacted by
the project.
Once project construction is complete and the Hwy 243 Bridge is open to traffic, existing travel patterns and
access across the St. Croix River between Franconia Township and Village of Osceola will be restored.
4.2.1.2 Accessibility
The proposed shared-use path on the north side of Hwy 243 would be located within public right of way. Design
and construction of all shared-use path and sidewalk facilities associated with the Hwy 243 Osceola Bridge
Project will comply with the provisions established by the ADA of 1990.
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4.2.1.3 Community Facilities and Public Services
Community facilities (schools and churches) within a half-mile radius of the project area are listed below. These
community facilities would not be impacted by the proposed project.
• Osceola United Methodist Church (306 River St, Osceola WI 54020)
• Trinity Evangelical Lutheran Church (300 Seminole Ave, Osceola WI 54020)
• Osceola Village Hall (310 Chieftain St, Osceola WI 54020)
• Housing Authority (403 2nd Ave, Osceola WI 54020)
Village of Osceola emergency service providers (e.g., fire, ambulance) rely on the Hwy 243 Bridge for
transportation and use the bridge to respond to calls on the Minnesota side of the St. Croix River. Emergency
service providers from Wisconsin also use Osceola Landing to access the St. Croix River and respond to incidents
on the Riverway.
Access to community facilities in the Village of Osceola will be maintained for Wisconsin residents throughout
construction. Minnesota residents accessing community facilities in the Village of Osceola would have to travel
longer distances during construction with closure of the Hwy 243 Bridge. The Contractor will be required to
maintain a boat ramp in the north parking lot at Osceola Landing for emergency services access to the Riverway.
Emergency vehicle access across the St. Croix River at the Hwy 243 Bridge and access to community facilities in
the Village of Osceola for Minnesota residents will be restored following completion of the project. A pull-off
area will be constructed on the south side of Hwy 243 near the Wisconsin abutment for emergency service
providers to use when responding to incidents on nearby trails and on the Riverway.
4.2.1.4 Community and Neighborhood Cohesion
The project would not displace any residents or businesses, change any access to Hwy 243 or local roadways, or
result in any permanent roadway closures. The project includes the reconstruction of an existing roadway and
bridge and would not create a new barrier to community or neighborhood cohesiveness. The proposed shared-
use path along the north side of Hwy 243 and the Hwy 243 Bridge would benefit the surrounding communities
by improving connectivity for non-motorized travel between the NPS’s Osceola Landing and Village of Osceola.
4.2.1.5 Transportation Sensitive Communities
Transportation sensitive communities that depend on public transportation, such as non-drivers, transit
dependent would not be impacted by the project. There are no transit routes that currently operate on the Hwy
243 Bridge. All pedestrians and bicyclists, including the elderly and handicapped, would benefit from the
proposed shared-use path between Osceola Landing and the Village of Osceola. The shared-use path and
sidewalks will be designed and constructed to meet ADA requirements. Landing areas will be constructed along
the shared-use path up the Wisconsin bluff to provide resting areas and mitigate for the greater than five
percent shared-use path grade.
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4.2.1.6 Mitigation
The project was designed to minimize impacts to travel patterns and accessibility, community facilities and
public services, and community and neighborhood cohesion. The social impacts, such as increased travel times
and altered access to community facilities, that would occur during construction of the project would be
mitigated by the creation of a Transportation Management Plan (TMP). This plan would help travelers
understand how to navigate the Hwy 243 Bridge closure during construction, access key destinations in the
project area (e.g., Osceola Landing, downtown Osceola). The TMP also would help ensure that communities
along detour routes are not substantially impacted by increased traffic during construction. No temporary
improvements along the detour route are anticipated; however, project staff will monitor traffic operations
during construction and implement temporary traffic control measures if problems arise. Project staff will
collaborate with emergency service providers to ensure access is maintained to resources throughout the area
to the extent possible and communicate upcoming closures and other changes to access.
4.2.2 Considerations Relating to Pedestrians and Bicyclists
Hwy 243 and the Hwy 243 Bridge do not have existing pedestrian or bicycle facilities. Pedestrian and bicycle use
is permitting on the roadway and bridge shoulders. Walkability/bikeability was identified as a secondary need
for the project. The NPS Osceola Landing and amenities in downtown Osceola include trip origins and
destinations for pedestrians and bicyclists, and the Hwy 243 Bridge is the only St. Croix River crossing connection
between these two locations. The narrow shoulders on the existing Hwy 243 Bridge create uncomfortable
conditions for most pedestrians and bicyclists. See the purpose and need statement in APPENDIX B (Purpose &
Need).
The project includes a 12-foot-wide shared-use path on the north side of Hwy 243 between the Wayside Rest
Area in Minnesota and the WIS-35 intersection in Wisconsin. The shared-use path would cross under the
proposed Hwy 243 Bridge, connecting with the north parking lot area in the Osceola Landing site. A 5-foot-wide
sidewalk will connect the shared-use path to a existing sidewalk in the northwest corner of the Hwy 243/WIS-35
intersection. The proposed design does not preclude a future crossing of Hwy 243 at the end of the shared-use
path in Osceola. This future crossing could connect to an existing local trail on the south side of Hwy 243 that
extends from the WIS-35 intersection into the Osceola Picnic Bluff property.
The Village of Osceola operates an existing trail under the Hwy 243 Bridge along the Wisconsin shoreline
(Cascade Trail). This trail connects recreational properties on both sides of Hwy 243. This trail connection will be
maintained with the project. A new trail connection will be constructed along the Wisconsin shoreline under the
proposed bridge. WisDOT will secure an agreement with the Village of Osceola following project construction to
permit the trail within highway right of way.
4.2.3 Environmental Justice
Executive Order 12898, Federal Actions to Address Environmental Justice in Minority Populations and Low-
income Populations, dated February 11, 1994, directed "each federal agency shall make achieving
environmental justice part of its mission by identifying and addressing, as appropriate, disproportionately high
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and adverse human health or environmental effects of its programs, policies, and activities on minority
populations and low-income populations in the United States…. The proposed project has federal funding and
federal permit requirements and is considered a federal project for purposes of compliance with the Executive
Order.”
FHWA Order 6640.23A FHWA Actions to Address Environmental Justice in Minority Populations and Low-Income
Populations establishes policies and procedures for the FHWA to use in complying with Executive Order 12898.
FHWA issued Order 6640.23A on June 14, 2012. For more information on the regulatory context of this subject
area, see the Environmental Justice (EJ) Standard Attachment (APPENDIX M (Environmental Justice Analysis)). A
summary is provided below.
4.2.3.1 EJ Study Area
The EJ study area is the geographic area where the proposed project has potential for human health or
environmental effects. A typical study area boundary consisting of the area approximately one-quarter mile
from the project area was applied for this analysis per MnDOT guidance.72 In addition, the temporary traffic
detour route north to Hwy 8 was included in the EJ study area, with the same one-quarter mile buffer from the
detour route. This analysis was completed in 2023, before separate MnDOT Metro guidance was released on
May 31, 2024. Therefore, this document relies on the quarter-mile buffer, rather than a 500-foot buffer which is
now included in Metro EJ guidance. All Census Block Groups that were partially or completely located within the
EJ study area were included in the analysis. The minority and low-income populations within these geographic
areas were included in the environmental justice analysis.
The EJ study area was investigated for the presence of readily-identifiable:
• minority and/or low-income populations residing in the EJ study area,
• community facilities in the EJ study area that serve minority and/or low-income populations, and
• businesses in the EJ study area that are owned by, employ, and/or serve minority and/or low-income
populations.
The investigation included review of demographic data, a desktop review using ArcGIS and American
Community Survey (ACS) 5-year data, consultation with knowledgeable local representatives, and public
outreach activities, as described below.
4.2.3.2 Minority Populations
Minority populations were identified from the American Community Survey Five-Year Estimates (2017-2021) at
the Census Block Group level. A minority community is generally defined as a community in which the minority
population is either 10 percentage points above the county average (Chisago County: 7.93%, Polk County:
5.62%), or at least 50 percent of the total geographic unit. Minority populations were determined by comparing
72 Minnesota Department of Transportation. Transportation Project Development Process (TPDP) Environmental Justice. Accessed in April
2024 and available at https://www.dot.state.mn.us/project-development/subject-guidance/environmental-justice/index.html.
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the percentage of the minority population for each Census Block Group in the EJ study area to that of Chisago or
Polk County, based on which county the block group is located within. No Census Block Group surpasses the
threshold to qualify as a minority/EJ population.
4.2.3.3 Low-Income Populations
Low-income populations were identified using income data for households collected from the 2017-2021
American Community Survey (ACS) at the Census Block Group level. For the purposes of this analysis, a low-
income community is defined as a community in which the low-income population is either 10 percentage
points above the county average (Chisago County: 6.55%, Polk County: 9.24%), or at least 50 percent of the total
geographic unit. The FHWA defines “low-income” geographies where the median household income is at or
below the Department of Health and Human Services (HHS) poverty guidelines. Poverty thresholds are updated
each year by the Census Bureau and vary based on family size and composition. The 2021 100% poverty
threshold for a family of four with two children was $26,500 according to the U.S. Department of Health and
Human Services (HHS).73 No Census Block Group surpasses the threshold to qualify as a low-income/EJ
population; however, the presence of a manufactured home park and other low-income/affordable housing
properties (located in the Village of Osceola, Polk County, WI) within the quarter-mile buffer indicate identifiable
EJ populations within the study area. These facilities are within the quarter-mile EJ study area but will not be
physically impacted by the proposed project.
4.2.3.5 Impacts
Executive Order 12898 requires that the proposed actions be reviewed to determine if there are
“disproportionately high and adverse” impacts on these populations. Disproportionately high and adverse effect
on minority and low-income populations means an adverse effect that:
• is predominately borne by a minority population and/or a low-income population, or
• will be suffered by the minority population and/or low-income population and is appreciably more
severe or greater in magnitude than the adverse effect that will be suffered by the non-minority
population and/or non-low-income population.
As described in this environmental document, the proposed action would have impacts on human health and
environment with regard to the following topics: social impacts, traffic impacts, construction noise impacts,
visual impacts, and air quality (dust/odor) impacts. Based on the analysis as discussed in (APPENDIX M
(Environmental Justice Analysis), there are no disproportionately high and adverse impacts to EJ populations in
the study area.
73 HHS. HHS 2021 Poverty Guidelines. Accessed in June 2024 and available at
https://www2.ed.gov/policy/highered/reg/hearulemaking/2021/povguid.pdf.
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4.2.3.6 Environmental Justice Finding
Readily identifiable low-income populations have been identified in the project area. However, after considering
mitigation, off-setting benefits, and public engagement, the adverse effects of the project will not be
predominately borne by a minority or low-income population, nor will they be appreciably more severe or
greater in magnitude than the adverse effect that will be suffered by the non-minority or non-low-income
population. Based on the nature, scale, and location of the Hwy 243 Osceola Bridge Project, the temporary
construction impacts (dust, odors, noise, and traffic detours) and visual impacts will be borne by all populations
near the proposed project. Therefore, the proposed action will not have disproportionately high and adverse
human health or environmental effects on any minority population or low-income population.
4.2.4 Economics
The project does not require right of way acquisition from any residence or business which would experience
economic impacts from additional property needs. Minor impacts to businesses/economic activity in the Village
of Osceola are anticipated to occur due to the temporary traffic detour which will result in delays and longer
travels times for those that would typically utilize the Hwy 243 Bridge to reach the Village of Osceola. Public
engagement would continue throughout construction to prepare and notify project-area residents, businesses,
and commuters for construction; listen to their concerns; and develop plans to reduce traffic detour impacts.
Temporary economic impacts during construction would be mitigated with the creation and implementation of
a Traffic Management Plan that would ensure motorists and other travelers are aware of construction timelines
and required detours to reach their destinations.
4.2.5 Relocation
The project does not require any relocations.
4.2.6 Right of Way
The project does not require any right of way or easements from adjacent property owners. A special use permit
will be acquired from the NPS for the use of Osceola Landing during construction.
4.2.7 Section 4(f) of the USDOT Act of 1966
Section 4(f) of the US Department of Transportation Act of 1966 is a federal law that protects publicly owned
parks, recreation areas, and wildlife and/or waterfowl refuges and publicly or privately owned significant historic
sites. Section 4(f) requirements apply to all transportation projects that require funding or other approvals by
the US Department of Transportation, including the FHWA. This law, commonly known as Section 4(f), is codified
in 23 USC Section § 138 and 49 USC Section § 303 and is implemented by the FHWA through the regulation in 23
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CFR Part 774. Additional guidance on the implementation of Section 4(f) is provided in the FHWA Section 4(f)
Policy Paper.74
4.2.7.1 Methodology
FHWA defines a Section 4(f) “use” as either a direct use or constructive use. A direct use occurs when land is
permanently incorporated into a transportation facility or when there is a temporary occupancy of land that is
adverse to a resource’s protection under Section 4(f). Constructive use occurs when a project's proximity
impacts are so severe that the protected activities, features, or attributes that qualify a resource for protection
under Section 4(f) are substantially impaired.
Before approving a project that "uses" a Section 4(f) resource, FHWA must find that there is no prudent and
feasible alternative and that the selected alternative minimizes harm to the resource. If there is a prudent and
feasible alternative that completely avoids Section 4(f) resources, it must be selected. If there is no prudent and
feasible alternative that avoids Section 4(f) resources, FHWA has some discretion in selecting the alternative
that causes the least harm to those resources.
In addition, FHWA regulations state that when a Section 4(f) use is anticipated, applicable regulations also
require consultations with the official having jurisdiction over the resource to verify the site’s significance and
coordinate conclusions on use of the land, including efforts to avoid or mitigate the impacts.
Section 4(f) resources were identified using of mapping and data sources for publicly owned lands in the project
area. Section 4(f) resources were reviewed with MnDOT, WisDOT, and FHWA to determine if these parcels had a
designated recreational use. FHWA is ultimately responsible for making the determination regarding the
applicability of Section 4(f) on any identified recreation and refuge resources.
4.2.7.2 Existing Conditions
Section 4(f) resources (recreational lands/parks/trails) identified within the general project vicinity are listed
below and shown in Figure 4-9. There is one historic property listed on the NRHP near the project area, known
as the Osceola Commercial Historic District. However, it is outside of the project area and will not be impacted
by the project; therefore, only recreational resources are reviewed in this section.
74 FHWA. Section 4(f) Policy Paper. Accessed in March 2024 and available at
https://www.environment.fhwa.dot.gov/legislation/section4f/4fpolicy.aspx.
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Figure 4-9. Section 4(f) Resources within the Project Area
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St. Croix National Scenic Riverway
The St. Croix National Scenic Riverway is a federally protected component of the wild and scenic rivers system
and a unit of the national park system administered by the National Park Service located northwest Wisconsin
and eastern Minnesota. The St. Croix National Scenic Riverway (Riverway) is known for its water quality, free
flowing condition, mussel diversity/ecology, human history, recreational opportunities, river conservation
history, geology, and scenery. As a wild and scenic river, the Riverway has Outstandingly Remarkable Values
(also known as ORVs) which guide it’s planning and management. The ORVs identified for the Lower St. Croix
River where the project is located are aquatic, cultural, geology, recreation, riparian, and scenic-aesthetic, in
addition to water quality and free-flowing condition. These are detailed further in APPENDIX N (Section 4(f)
Involvement – De Minimis Determination and Temporary Occupancies).
The proposed project is within the Lower St. Croix National Scenic Riverway, which includes Osceola Landing in
Franconia Township, Minnesota. The Riverway accommodates hiking, biking, picnicking, scenic viewing,
photography, bird watching, swimming, motorized and non-motorized boating, fishing, camping, snowmobiling,
cross-country skiing, and interpretive programs.
St. Croix River State Water Trail
The Minnesota State Water Trail system is a system of rivers and waterways located throughout Minnesota. The
Minnesota DNR manages the Minnesota State Water Trail system for canoeing, kayaking, boating, and camping.
The St. Croix River is part of the Minnesota State Water Trail system. The Hwy 243 Bridge crosses the St. Croix
River State Water Trail at river mile 45.5.
Osceola Picnic Bluff
The Osceola Picnic Bluff property is located along the Wisconsin shoreline on the south side of Hwy 243. The
Osceola Picnic Bluff property is owned by the Village of Osceola. The Osceola Picnic Bluff consists primarily of
undeveloped, open space with trails for hiking and snowshoeing.
Gristmill Park
The Gristmill Park property is located along the north side of Osceola Creek, near the Hwy 243 and Cascade
Street (WIS-35) intersection, in Wisconsin. It is located behind the Watershed Café. The Gristmill Park property is
owned by the Village Osceola. The Gristmill Park property consists primarily of undeveloped, open space with
trails for hiking and snowshoeing, as well as seating and tables for picnicking.
Cascade Falls/Wilke Glen
The Cascade Falls/Wilke Glen property is located along the Wisconsin shoreline on the north side of Hwy 243.
Osceola Creek bisects the Cascade Falls/Wilke Glen property. The confluence of Osceola Creek with the St. Croix
River is west of the Cascade Falls/Wilke Glen property along with St. Croix River shoreline. The Cascade
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Falls/Wilke Glenn property is owned by the Village of Osceola. The Cascade Falls/Wilke Glen property consists
primarily of undeveloped, open space with trails for hiking and snowshoeing.
Cascade Trail (Local Trail Along Wisconsin Shoreline)
Cascade Trail is along the Wisconsin shoreline crossing under the Hwy 243 Bridge. This trail connects the
Cascade Falls/Wilke Glen property on the north side of Hwy 243 with the Osceola Picnic Bluff property on the
south side of Hwy 243. A canoe landing and small dock is in the St. Croix River on the south side of the Hwy 243
Bridge in WisDOT right of way. River users can use this landing and dock and trails to access amenities in
downtown Osceola. Portions of Cascade Trail and the canoe landing were improved in 2014 with a Federal
recreational trail grant (see Wisconsin DNR correspondence in APPENDIX J (Agency Correspondence)). This trail
and dock is owned by the Village of Osceola. There is no current WisDOT State Hwy Connection Permit for the
trail and landing to be in highway right of way.
4.2.7.3 Section 4(f) Involvement
Properties within the project area protected by Section 4(f) were evaluated to determine if there would be a use
of the property, as defined in 23 CFR § 774.17. The project was evaluated for temporary occupancy, de minimis,
and constructive use of Section 4(f) resources within the project area. Definitions for each is provided in the
FHWA’s Section 4(f) Policy Paper.75
The project is located within MnDOT and WisDOT right of way and would not require permanent acquisition of
land from any of the Section 4(f) resources identified above. The following sections summarize Section 4(f)
involvement for the Hwy 243 Osceola Bridge Project.
St. Croix National Scenic Riverway
APPENDIX N (Section 4(f) Involvement – De Minimis Determination and Temporary Occupancies). includes the
Section 4(f) de minimis determination notice of intent request for the St. Croix National Scenic Riverway. The
OWJ for the St. Croix National Scenic Riverway is NPS. FHWA intends to make a determination that the project
meets the requirements for a Section 4(f) de minimis finding for the St. Croix National Scenic Riverway. MnDOT
has been coordinating closely with the NPS on impacts and associated mitigation to the Riverway. NPS
coordination since 2021 is documented in APPENDIX N (Section 4(f) Involvement – De Minimis Determination
and Temporary Occupancies), as well as proposed mitigation measures for minimizing impacts to the Riverway.
Section 4(f) mitigation measures will be included in this project’s Environmental Management Plan (APPENDIX F
(Environmental Management Plan)).
FHWA will request concurrence from NPS on the assessment of effects to the St. Croix National Scenic Riverway
following the public comment period on this EA/EAW. Any NPS agreement with the Section 4(f) de minimis
75 FHWA. Section 4(f) Policy Paper. Accessed in March 2024 and available at
https://www.environment.fhwa.dot.gov/legislation/section4f/4fpolicy.aspx.
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determination for the St. Croix National Scenic Riverway does not confer an affirmative Section 7(a)
determination. NPS will prepare a Section 7(a) evaluation and determination for the Hwy 243 Osceola Bridge
Project in accordance with the NWSRA.
Section 4.2.7.4 (Constructive Use) lists the situations addressed in 23 CFR 774.15(e) regarding constructive use.
The project does not constitute a Section 4(f) constructive use of the St. Croix National Scenic Riverway as
identified below.
• The project is not a Type I Project under 23 CFR 772.5. The project does not add highway capacity and
does not change traffic volumes compared to the No Build Alternative. The project includes
reconstruction of an existing highway and bridge along its existing alignment through the St. Croix
National Scenic Riverway. Therefore, there would be no projected noise increase attributable to the
project.
• The proposed project would not substantially impair the scenic/aesthetic features of the St. Croix
National Scenic Riverway. The project follows the existing highway and bridge alignment and will
remove one bridge pier from the Riverway. In general, reconstructing the highway and bridge along the
same established alignment is beneficial by minimizing impacts to the adjacent natural and cultural
features. The reduced structure depth of the proposed bridge and fewer piers will create more open
views along the St. Croix River compared to existing conditions. The Visual Quality Manual describes
guidelines for visual mitigation strategies, including minimizing the project footprint, minimal
constructed features, and use of natural materials and colors to blend into the environment. The NPS
participated in the Visual Quality Manual development as a member of the Visual Quality Advisory
Committee (VQAC).
• The project does not change or restrict access to the St. Croix National Scenic Riverway.
• The vibration impact from construction or operation of the project would not substantially impair the
use of the St. Croix National Scenic Riverway. There are no historic buildings in the St. Croix National
Scenic Riverway adjacent to the project that would be susceptible to vibrations. Buildings adjacent to
construction staging areas at the north end of Osceola Landing (e.g., pump house, comfort station)
would be protected during construction. Any physical damage would be restored. Operational traffic
induced vibrations are less than any known criteria for structural damage to buildings.
• The project would not substantially diminish the value of wildlife habitat or use of the St. Croix National
Scenic Riverway. The project avoids and minimizes impacts to adjacent wildlife habitat in the St. Croix
National Scenic Riverway by following the existing highway and bridge alignment. The proposed bridge
type was identified to avoid mussel habitat along the shorelines of the St. Croix River. Mussels will be
relocated from the work area prior to the start of construction. The river bottom will be restored after
construction with removal of earthen causeways. Section 4.1.14 (Fish, Wildlife, Plant Communities, and
Sensitive Ecological Resources) describes minimization and mitigation measures for permanent and
temporary impacts to wildlife, fisheries, and mussels. One of the mitigation measures includes
construction of a wildlife crossing under Hwy 243 west of Osceola Landing, improving wildlife
connectivity backwater shallow marshes and floodplains in the Riverway.
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St. Croix River State Water Trail
The St. Croix River State Water Trail crossing under the Hwy 243 Bridge would be periodically closed during
project construction. APPENDIX N (Section 4(f) Involvement – De Minimis Determination and Temporary
Occupancies ) includes correspondence between the Minnesota DNR and MnDOT regarding the St. Croix River
State Water Trail closure. Section 4(f) temporary occupancy conditions as identified in 23 CFR 774.13(d) are
listed in the correspondence with Minnesota DNR. FHWA concurs that the project meets the requirements for a
Section 4(f) temporary occupancy exception and does not constitute a Section 4(f) use of the St. Croix River
State Water Trail, including constructive use (See Section 4.2.7.4 Constructive Use).
Osceola Picnic Bluff
The project would not result in a Section 4(f) use of Osceola Picnic Bluff, including constructive use (see Section
4.2.7.4 Constructive Use). No new right of way would be acquired from Osceola Picnic Bluff. Preliminary
construction limits do not encroach into Osceola Picnic Bluff. Trails within the Osceola Picnic Bluff property
would remain open during project construction. Therefore, no Section 4(f) involvement is necessary.
Gristmill Park
The project would not result in a Section 4(f) use of Gristmill Park, including constructive use (see Section 4.2.7.4
Constructive Use). No new right of way would be acquired from Gristmill Park. Preliminary construction limits do
not encroach into Gristmill Park. Therefore, no Section 4(f) involvement is necessary.
Cascade Falls/Wilke Glen
The project would not result in a Section 4(f) use of Cascade Falls/Wilke Glen, including constructive use (see
Section 4.2.7.4 Constructive Use). No new right of way would be acquired from Cascade Falls/Wilke Glen.
Preliminary construction limits do not encroach into Cascade Falls/Wilke Glen. Trails within the Cascade
Falls/Wilke Glen property would remain open during project construction. Therefore, no Section 4(f)
involvement is necessary.
Cascade Falls Trail (Local Trail Along Wisconsin Shoreline)
The project would result in a temporary occupancy of the Cascade Falls Trail along the Wisconsin shoreline of
the St. Croix River. The portion of this trail that would be temporarily closed is beneath the Hwy 243 Bridge. No
new right of way would be acquired for temporary occupancy of this trail because it is within existing WisDOT
right of way. The OWJ of this property is the Village of Osceola APPENDIX N (Section 4(f) Involvement – De
Minimis Determination and Temporary Occupancies) includes correspondence between the Village of Osceola
and MnDOT regarding the Cascade Falls Trail closure. Section 4(f) temporary occupancy conditions as identified
in 23 CFR 774.13(d) are listed in the correspondence with the Village of Osceola. FHWA concurs that the project
meets the requirements for a Section 4(f) temporary occupancy exception and does not constitute a Section 4(f)
use of the Cascade Falls Trail, including constructive use (see Section 4.2.7.4 Constructive Use).
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4.2.7.4 Constructive Use
A constructive use occurs when a project does not incorporate land from a Section 4(f) resource, but the
project’s proximity impacts are so severe that the protected activities, features, or attributes that qualify the
resource for protection under Section 4(f) are substantially impaired. Substantial impairment only occurs when
the protected activities, features, or attributes are substantially diminished (23 CFR 774.15(a)).
23 CFR 774.15(e) describes the situations where FHWA has determined that constructive use would occur.
These situations do not apply to Section 4(f) resources in the project study area (i.e., St. Croix River State Water
Trail, Osceola Picnic Bluff, Gristmill Park, Cascade Falls/Wilke Glen, and Cascade Falls Trail) as described below.
• The projected noise level increase attributable to the project substantially interferes with the use and
enjoyment of a noise-sensitive of a property protected by Section 4(f).
The Hwy 243 Osceola Bridge Project is not a Type I project as established in 23 CFR 772.5. Therefore, the
project requires no analysis for highway traffic noise impacts. The project does not involve a highway on
a new location, added capacity, construction of new through lanes or auxiliary lanes, or substantial
changes in the horizontal or vertical alignment of the roadway that exposes noise sensitive land uses to
an existing highway noise source (see Section 4.1.19 Noise).
• The proximity of the proposed project substantially impairs aesthetic features or attributes of a property
protected by Section 4(f), where such features or attributes are considered important contributing
elements to the value of the property.
The project does not substantially impact aesthetic features or attributes of a Section 4(f) property.
Table 4-11 in Section 4.1.16 (Visual) summarizes the visual impacts of the project by key viewsheds in
the project area. In general, the overall degree of impact on visual compatibility and viewer sensitivity at
key viewsheds is neutral. Visual mitigation strategies, including context-sensitive bridge aesthetics,
vegetation restoration, and trail wayfinding signage will be implemented as identified in the Visual
Quality Manual.
• The project results in a restriction of access which substantially diminishes the utility of a significant
publicly-owned park, recreation area, or a historic site.
The project does not result in a restriction or change in access to Section 4(f) properties.
• The vibration impact from construction or operation of the project substantially impairs the use of a
Section 4(f) property, such as projected vibration levels that are great enough to physically damage a
historic building or substantially diminish the utility of the building, unless the damage is repaired and
fully restored consistent with the Secretary of the Interior’s Standards for the Treatment of Historic
Properties.
Construction-related, vibration-causing activities of the project would not substantially impair the use of
Section 4(f) properties. Construction-related, vibration-causing activities of the project include pile
driving, compaction, and rock scaling along the Wisconsin bluff. The project will not include blasting.
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These activities are temporary and would be limited to the construction period. There are no buildings
on Section 4(f) properties adjacent to the project that would be physically damaged or diminished with
construction of the project.
Vibration impacts from operation of the project would not substantially impair the use of Section 4(f)
properties. There are no buildings on Section 4(f) properties adjacent to the project that would be
physically damaged or diminished with highway-induced traffic vibrations.
MnDOT CRU determined that there would be “no historic properties” affected by the Hwy 243 Osceola
Bridge Project. The Minnesota SHPO and Wisconsin SHPO concurred with the no historic properties
finding.
• The ecological intrusion of the project substantially diminishes the value of wildlife habitat in a wildlife
and waterfowl refuge adjacent to the project, substantially interferes with the access to a wildlife and
waterfowl refuge when such access is necessary for established wildlife migration or critical life cycle
processes, or substantially reduces the wildlife use of a wildlife and waterfowl refuge.
None of the Section 4(f) properties adjacent to the project are designated wildlife or waterfowl refuges.
These properties function primarily for park/recreational area purposes and do not function primarily as
a refuge.
4.2.8 Section 6(f)/Land and Water Conservation Fund Act
Section 6(f) of the Land and Water Conservation Fund Act (LWCF) requires that any resource which has received
LWCF funds be protected from conversions to non-recreation uses. Property subject to LWCF protection cannot
be converted to non-recreation uses unless approved by a state’s DNR and/or NPS, and replacement land of at
least equal fair market value and reasonably equivalent usefulness is provided. This project was reviewed and no
properties subject to Section 6(f) requirements are located within the project limits.
4.2.9 Noise
The project would not result in substantial horizontal or vertical alignment alteration and does not add capacity
to an existing roadway. The project also does not add a new or substantially alter a weigh station, rest stop, ride-
share lot, or toll plaza. The proposed project meets the definition of a Type III project; therefore, it does not
require a traffic noise analysis under 23 CFR 772. See agency correspondence in APPENDIX J (Agency
Correspondence). Section 4.1.19 Noise provides additional detail on noise.
Construction noise for the duration of the project is anticipated to affect the project area and surrounding
community. Advance notice will be provided to affected communities for any abnormally loud construction
activities. Any associated high-impact equipment noise such as pile driving, pavement sawing, or jack
hammering will be unavoidable with construction of the Preferred Alternative. The use of pile drivers, pavement
sawing, and jack-hammering equipment will be prohibited during nighttime hours. Measures regarding
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construction noise will be included in this project’s Environmental Management Plan (APPENDIX F
(Environmental Management Plan)).
4.2.10 Farmland Protection Policy Act
The Farmland Protection Policy Act (FPPA) was enacted as a subtitle of the 1981 Farm Bill to minimize the extent
to which deferral programs contribute to the unnecessary conversion of farmland to non-agricultural uses (P.L.
97-98, Sec. 1539-1549; 7 U.S.C. 4201, et seq.). FPPA requires federal agencies to examine the impact of projects
that convert farmland to non-agricultural uses. If a federal agency, or its representative, determine that a
project will impact agricultural lands, a Farmland Conversion Impact Rating Form (Form AD-1006) is completed
to rate the relative impact of the project.
The project is not anticipated to cause any adverse impact to prime farmlands, unique farmlands, farmlands of
statewide or local importance, or agricultural land or operations. No agricultural land will be acquired and no
farm will be severed or triangulated. The project will not have a significant effect upon agricultural production in
Chisago County, Minnesota or Polk County, Wisconsin.
4.2.11 Section 7 of the Endangered Species Act
Section 7 of Endangered Species Act of 1973, as amended, requires each federal agency to review any action
that it funds, authorizes, or carries out to determine whether it may affect threatened, endangered, or proposed
species or listed critical habitat. Federal agencies (or their designated representatives) must consult with the
USFWS if any such effects may occur as a result of their actions. Consultation with the USFWS is not necessary if
the proposed action will not directly or indirectly affect listed species or critical habitat. If a federal agency finds
that an action will have no effect on listed species or critical habitat, it should maintain a written record of that
finding that includes the supporting rationale.
Section 4.1.14 Fish, Wildlife, Plant Communities, and Sensitive Ecological Resources (Rare Features) of this
document details state and federally protected species and contains additional information regarding impacts
and mitigation commitments. A Biological Assessment has been submitted for the project and the USFWS will
release a Biological Opinion (pending). The Biological Assessment can be found in APPENDIX K (Biological
Assessment).
4.2.12 Section 106 of the National Historic Preservation Act
Section 106 of the National Historic Preservation Act of 1966 requirements apply to projects that are considered
a federal undertaking (i.e., projects that include federal funding or require a federal permit). 36 CFR 800 codifies
regulations regarding the Section 106 review process. It is anticipated that construction of the Hwy 243 Osceola
Bridge Project will include federal funding and, therefore, the project is subject to Section 106 requirements.
These requirements are detailed in Section 4.1.15.4 Section 106 Finding. Correspondence regarding Section 106
from both MnDOT and WisDOT can be found in APPENDIX J (Agency Correspondence).
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MnDOT CRU determined that there would be “no historic properties” affected by the Hwy 243 Osceola Bridge
Project. The Minnesota SHPO and Wisconsin SHPO concurred with the no historic properties finding.
4.2.13 Section 7(a) of the National Wild and Scenic Rivers Act
The St. Croix National Scenic Riverway was established as a National Wild and Scenic River under the Wild and
Scenic Rivers Act of 1968 (16 USC 1271-1287, Public Law (PL) 90-542) (Act). The Lower St. Croix National Scenic
Riverway, from St. Croix Falls, Wisconsin to the confluence with the Mississippi River, was added to the system
in 1972. Section 7(a) of the Act directs federal agencies to protect the free-flowing condition, water quality, and
ORVs of wild and scenic rivers. NPS is responsible for making evaluations and determinations under Section 7(a)
of the Act. The Hwy 243 Osceola Bridge Project is subject to review by NPS under Section 7(a) of the Act.76
NPS is a Cooperating Agency for the Hwy 243 Osceola Bridge Project. NPS participated in Cooperating Agency
meetings and reviews of the alternatives evaluation report. NPS provided concurrence on identification of
Alternative B as the Preferred Alternative on June 21, 2023. MnDOT and WisDOT facilitated recurring meetings
with NPS to discuss project development, share information, and answer questions. MnDOT, WisDOT, and NPS
coordination meetings are listed in the Section 4(f) de minimis documentation in APPENDIX N (Section 4(f)
Involvement – De Minimis Determination and Temporary Occupancies).
NPS will evaluate the temporary and permanent impacts of the project with respect to the free-flowing
condition, water quality, and outstandingly remarkable values (ORVs) applicable to the segment of the St. Croix
River at the Hwy 243 Bridge. Riverway ORVs at the Hwy 243 Bridge include aquatic ORV, cultural ORV, recreation
ORV, riparian ORV, and scenic-aesthetic ORV. NPS will determine if the project would or would not result in a
direct and adverse effect on these characteristics of the St. Croix National Scenic Riverway.
NPS prepared an initial assessment of the Hwy 243 Osceola Bridge Project in support of this EA/EAW. APPENDIX
P (NPS Section 7(a) Correspondence) includes correspondence from NPS. The NPS will publish their Section 7(a)
evaluation and determination at the conclusion of the environmental review process for the project.
Coordination with NPS will continue through final design and permitting, including bi-weekly meetings as
needed. MnDOT will apply for a special use permit from NPS for use of Osceola Landing for construction staging.
MnDOT and NPS also will complete inter-agency agreements for project construction, including a cooperative
construction agreement for Osceola Landing improvements, funding for NPS visitor service assistant (VSA) staff
during construction, and replacement of St. Croix National Scenic Riverway highway signs. Coordination with
NPS will continue through project construction with implementation of mitigation measures (see APPENDIX F
(Environmental Management Plan)).
76 US Department of Interior. National Park Service. St. Croix National Scenic Riverway Foundation Document accessed April 2024 and
available at https://www.nps.gov/sacn/learn/management/foundation-document.htm.
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5. PUBLIC AND AGENCY INVOLVEMENT (AND
PERMITS/APPROVALS)
5.1 Informational Process
5.1.1 Public Engagement
5.1.1.1 Public Involvement Plan
A public involvement plan (PIP) was developed and implemented early in the project development process. This
plan has helped to establish communication between MnDOT and the public and has given MnDOT a better
understanding of the concerns that the public and agencies have about the proposed project. It has also given
the public and agencies knowledge about what it is that MnDOT is trying to accomplish with the project, and the
standards, procedures, and constraints that MnDOT needs to consider while developing the project. The PIP
documents the goals, strategies, and methods for engaging with the public. See below for the stakeholder
groups representing the PIP. Elements of the public involvement plan include public information meetings,
stakeholder meetings, passive engagement, pop-up events, virtual meetings, virtual office hours, interactive
surveys and maps, a project website, project email and phone, and written and virtual
comments/communications.
5.1.1.2 Stakeholder Groups
Several stakeholder groups were identified for the Hwy 243 Osceola Bridge Project. Stakeholders are staff and
officials from partner organizations that are affected by the project. Stakeholders are directly involved in the
steering, management, or development of the project. All stakeholders will be engaged throughout the project
process both through invitations to public meetings and through meetings of the project advisory groups. A brief
description of each stakeholder group and their role is listed below.
• Technical Advisory Committee (TAC): The Technical Advisory Committee is comprised of management
staff from MnDOT and partnering agencies. Its role is to be the technical project partner. The TAC’s
responsibilities include providing recommendations on project decision points/major milestones and
providing input in the development of the project.
o MnDOT
o WisDOT
o Consultant groups
o FHWA
• Local Advisory Committee (LAC): The Local Advisory Committee is comprised of local agency and
government leaders. The purpose of the LAC is to provide feedback on project approach, public
engagement, and project goals.
o MnDOT
o WisDOT
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o NPS
o Chisago County, MN
o Franconia Township, MN
o Polk County, WI
o St. Croix Falls, WI
o Consultant groups
o Taylors Falls, MN
o Town of Osceola, WI
o Village of Dresser, WI
o Village of Osceola, WI
• Visual Quality Advisory Committee (VQAC): The VQAC will incorporate agency, stakeholder, and public
input. Visual quality planning will utilize a systematic Context Sensitive Solutions (CSS) process that
explores, documents, and illustrates consensus decision-making. The purpose of the VQAC is to provide
feedback on the visual quality planning process and develop the VQM.
o MnDOT
o WisDOT
o NPS
o Chisago County, MN
o Members of the public
o Osceola Chamber, WI
o Polk County, WI
o Taylors Falls, MN
o St. Croix Falls, WI
o Village of Dresser, WI
o Village of Osceola, WI
5.1.1.3 Public Meetings
Several public and agency meetings were held and newsletters sent out between March 2022 and June 2024.
See Table 5-1. Public Engagement Activities for a summary of Public Engagement Activities and the general
themes of public comments.
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Table 5-18. Public Engagement Activities
Engagement Activity Description
Virtual Public Meeting
March 3, 2022
Online
Over 100 residents attended the meeting (Total: 126). Seven people
viewed the online recording.
Meeting materials, including video recording of the virtual meeting
presentation, were posted to the project website. Members of the public
were able to access the materials online and provide comments through
the online questionnaire and comment portal. Hard copies of the
presentation and comment cards were placed at City Hall and the Library
in Osceola.
Fifty-three comments were received during this meeting. One hundred
twenty-seven total comments were gathered during the entirety of this
engagement period (March 2022). General themes of comments
received included:
• Alternatives design details
• Concerns about construction impacts on bridge
crossing/commutes
• Pedestrian and bicycle considerations
• Safety needs
• Noise concerns
In-person Public Meeting
May 10, 2023
Village of Osceola Township
offices
(Village of Osceola)
Over 100 people attended the meeting. Thirty individuals viewed the
online recording.
The meeting included a short presentation from the project team,
project information boards, and informal opportunities for the public to
ask questions and discuss with project representatives.
Six comments were received from comment cards, and another seven
comments were submitted online through the project website.
General themes of comments received included:
• Concerns about bridge closure timeframe
• Other alignment options
• Construction phasing techniques
• Pedestrian and bicycle facility needs
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Engagement Activity Description
In-person Public Meeting
June 25, 2024
Osceola High School (Large Group
Instruction Room)
(Village of Osceola)
More than 55 people attended the meeting.
The purpose of the meeting was to share information from the visual
quality management process and provide schedule updates. The meeting
included a short presentation by the MnDOT Project Manager, project
information boards, and informal opportunities for the public to ask
questions and discuss with project representatives. The presentation
was posted to the project website following the meeting.
General themes of comments received included:
• Hwy 243 and WIS 35 intersection in Osceola
• Project schedule and timing of construction
• Trail connectivity in Wisconsin
5.1.2 Project Management Team
A Project Management Team (PMT) was formed in November 2020 to help provide community input into the
project process and to encourage communication between the MnDOT and the affected communities. The PMT
held 38 meetings between November 2020 and January 2024. The PMT is composed of representatives from
each county, city and township directly affected by the proposed project. There are also members representing
the following organizations:
• FHWA
• MnDOT
• WisDOT
• Consultant groups
5.1.3 Agency Coordination
5.1.3.1 Cooperating and Participating Agencies
MnDOT, WisDOT and FHWA prepared an Agency Coordination Plan for the Hwy 243 Osceola Bridge Project. The
purpose of the Agency Coordination Plan is to guide DOT interactions with Cooperating and Participating
Agencies for the Hwy 243 Osceola Bridge Project. The Agency Coordination Plan describes agency roles and
responsibilities, agency expectations, concurrence points, and project milestones. Cooperating and Participating
Agency roles are summarized below. The Agency Coordination Plan is available for review from the MnDOT
Project Manager upon request (see contact information in Section 4.1.2 Proposer – Proposer).
Table 5-2. Cooperating and Participating Agencies lists the Cooperating and Participating Agencies of the Hwy
243 Osceola Bridge Project.
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Table 5-19. Cooperating and Participating Agencies
Joint Lead Agencies Cooperating Agencies Participating Agencies
• FHWA (lead federal agency)
(Minnesota and Wisconsin
Division Offices)
• MnDOT (lead state agency)
• WisDOT
• NPS
• USACE
• EPA
• USFWS
• USCG
• MnDNR
• WisDNR
• Village of Osceola
• Franconia Township
Four Cooperating and Participating Agency meetings were held during the development of this EA/EAW. The
focus of these meetings was to review the project needs, discuss the alternatives evaluation process and results,
and to solicit input from agency representatives. Cooperating and Participating Agency meetings will be on-
going through the conclusion of the environmental review process.
Cooperating Agencies
A Cooperating Agency is any federal agency that has jurisdiction by law or special expertise to assist with the
environmental process. Federally Recognized Tribes are Cooperating Agencies when project effects are on lands
of Tribal interest. Five Federal agencies accepted the invitation to be Cooperating Agencies for the Hwy 243
Osceola Bridge Project (see Table 5-2. Cooperating and Participating Agencies).
Cooperating Agencies provide input related to relevant areas of expertise during the evaluation of alternatives
and development of the EA/EAW. MnDOT, WisDOT and FHWA will request formal written agreement from
Cooperating Agencies at three milestone points in the project development process for Hwy 243 Bridge. These
milestones are referred to as “Concurrence Points.” Table 5-3. Hwy 243 Osceola Bridge Project Concurrence
Points lists the Hwy 243 Bridge concurrence points and current status.
Table 5-20. Hwy 243 Osceola Bridge Project Concurrence Points
Concurrence Point Description Status
Concurrence Point #1 Purpose and need statement and
evaluation criteria
Completed July 2021
Concurrence received from USACE,
NPS, and EPA
Concurrence Point #2 Alternatives evaluation and
identification of Preferred
Alternative
Completed June 2023
Concurrence received from
USFWS, NPS, and EPA
Concurrence Point #3 Mitigation measures and
enhancements
To be completed
Participating Agencies
Participating Agencies include federal, state, or local agencies or Federally Recognized Tribes that have an
interest in the Hwy 243 Osceola Bridge Project. Four state and local agencies accepted the invitation to be
Participating Agencies for the Hwy Osceola Bridge Project (see Table 5-2. Cooperating and Participating
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Agencies). Participating Agencies agree to identify issues of concern regarding the project’s potential impacts
and provide meaningful and timely input throughout the environmental review process.
5.1.3.2 Agency Coordination Meetings
MnDOT and WisDOT hosted agency coordination meetings throughout the environmental review process to
communicate project status and preliminary design development, discuss agency comments and feedback, and
to facilitate future permitting activities. Agency partners included the Cooperating and Participating Agencies
listed above. Representatives from MPCA attended meetings regarding stormwater management.
Representatives from Minnesota Board of Soil and Water Resources (BWSR), Chisago County, and Chisago Soil
and Water Conservation District (SWCD) were invited to participate in the wetland delineation review process.
NPS Coordination Meetings
More than 20 coordination meetings were hosted by MnDOT and WisDOT with NPS St. Croix National Scenic
Riverway staff during the environmental review for the Hwy 243 Osceola Bridge Project. The purpose of these
meetings was to provide project updates, share information, and discuss topics relevant to the NPS Section 7(a)
evaluation process under the NWSRA. Coordination meetings with NPS staff will be on-going through issuance of
the Section 7(a) determination and project construction.
USFWS/DNR Coordination Meetings
More than 15 meetings were hosted by MnDOT and WisDOT with USFWS, Minnesota DNR, and Wisconsin DNR
staff during the environmental review for the Hwy 243 Osceola Bridge Project. The purpose of these meetings
was to provide project updates, share information, discuss topics relevant to the Section 7 Endangered Species
Act process, and discuss potential impacts and mitigation for state-listed species. APPENDIX K (Biological
Assessment) includes the Biological Assessment. The USFWS Biological Opinion is in development and will be
issued prior to the NEPA decision document. Implementation of mitigation measures will be coordinated with
USFWS. Coordination with Minnesota DNR and Wisconsin DNR will be on-going through the permitting process
(e.g., state incidental take permitting).
5.2 Summary of Early Coordination Comments
5.2.1 Minnesota
These agencies and MnDOT functional groups responded and provided comments about the project after the
initial Early Notification Memo (ENM) in April 2020:
• United States Coast Guard – April 9, 2018
• MnDOT Contaminated Materials Management – April 17, 2020
• MnDOT Noise and Air/GHG – April 17, 2020
• MnDOT Rest Area Program – April 17, 2020
• MnDOT State Entrance Monument Program – April 17, 2020
• MnDOT Metro Traffic – April 20, 2020
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• MnDOT Right of Way Considerations – April 24, 2019
• MnDOT CRU – April 30, 2020
• NPS St. Croix National Scenic Riverway – May 18, 2020
• MnDOT OES Vegetation Review – May 21, 2020
• MnDOT OES Threatened and Endangered Species – June 17, 2020
• MnDOT Regulated Materials Management – July 2, 2020
• MnDNR Transportation Liaison Response – July 14, 2020
• MnDOT Wetlands and Protected Species – March 10, 2021
• MnDOT Wetlands Coordination – October 20, 2023
An ENM update was distributed for the project (which included the Preferred Alternative layout and preliminary
construction limits) in December 2023. The following MnDOT functional groups provided further comments:
• MnDOT OES Vegetation Review – December 19, 2023
• MnDOT Noise – December 21, 2023, January 2, 2024
• MnDOT State Entrance Monument Program – December 29, 2023
• MnDOT Bridge Projects – January 22, 2024
• MnDOT Regulated Materials – January 22, 2024
• MnDOT Contaminated Materials Management – January 31, 2024
• MnDOT CRU to MnSHPO APE correspondence – April 10, 2024
• MnSHPO correspondence to MnDOT CRU – May 7, 2024
All initial ENM responses that are still relevant, as well as ENM update responses can be found in APPENDIX J
(Agency Correspondence).
5.2.2 Wisconsin
These agencies responded and provided comments about the project:
• WisDNR DNR Initial Review – December 20, 2023
• WisDOT Section 106 Historical/Archaeological Review – February 5, 2024
See the Wisconsin DNR Initial Review Letter and Section 106 Review Form (DT1635) in APPENDIX J (Agency
Correspondence).
5.3 Public Comment Period and Public Hearing
Comments from the public and agencies affected by this project are requested during the public comment
period described in the transmittal letter distributing this Environmental Assessment. A combined public
informational meeting/public hearing will be held after this Environmental Assessment has been distributed to
the public and to the required and interested federal, Native American Tribes, state, and local agencies for their
review.
At the informational meeting/public hearing, preliminary design layouts for the alternatives under consideration
along with other project documentation will be available for public review. The public will also be given the
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opportunity to express their comments, ideas, and concerns about the proposed project. These comments will
be received at the hearing and during the remainder of the comment period and will become a part of the
official hearing record.
5.4 Report Distribution
Copies of this document have been sent to agencies, local government units, libraries, and others as per
Minnesota Rule 4410.1500 (Publication and Distribution of an EAW).
5.5 Process Beyond the Hearing
Following the comment period, MnDOT and the FHWA will make a determination as to the adequacy of the
environmental documentation. If further documentation is necessary it could be accomplished by preparing an
EIS, by revising the Environmental Assessment, or clarification in the Findings of Fact and Conclusion, whichever
is appropriate.
When the environmental documentation is determined adequate, MnDOT will choose a project alternative,
either the No Build or one of the alternatives under consideration.
If an EIS is not necessary, as currently anticipated, MnDOT will prepare a "Negative Declaration" for the state
environmental requirements. MnDOT will also prepare a request for a FONSI that will be submitted to the
FHWA. If the FHWA agrees that this finding is appropriate, it will issue a FONSI.
Notices of the federal and state decisions and availability of the above documents will be placed in the Federal
Register and the Minnesota Environmental Quality Boards (MEQB) Monitor. MnDOT will also distribute the
Negative Declaration and FONSI to the Environmental Assessment Worksheet distribution list and publish
notices in local newspapers announcing the environmental and project alternative decisions that were made.