6. Discussion on Bliss addition stormwater studySC DILA
Staff Report
Date of Meeting: June 6, 2018
To: City Council
From: Neil Soltis, Administrator
Re: Bliss Addition Stormwater Study
Background: At the discussion regarding stormwater issues at the May Work Session Staff was
directed to investigate whether the Carnelian -Marine Watershed District has previously prepared a
stormwater plan for the Bliss addition and to pursue a plan for stormwater treatment that would
result in improvements to water quality.
The Watershed District cannot locate a previous stormwater plan for the Bliss Addition. City
Engineer Ryan Goodman has submitted the following regarding the development of a plan.
Below are some preliminary thoughts. I am assuming that flood control is the primary
goal, but water quality BMPs will also be included as well.
Assumptions:
1) We will require detailed survey (not included below/need to have survey
coordinator review the agreed upon area prior to preparing an estimate) to understand
the minor changes in surface topography that may be leading to the flooding condition
and or to conclude directional flows.
2) Water quality will be a goal of the stakeholders and will be included in plan
development.
3) High level costs will be required based on preliminary design, but final design
and final costs will be competed at a future date.
Preliminary Scope:
• Meetings — $2,000 - $3,000
o Assume one kickoff meeting and one additional stakeholder meeting.
• Hydraulic and Hydrologic Modeling - $4,000 - $6,000
o Existing and proposed conditions
• Develop Preliminary Solutions for Flood Mitigation - $4,000 - $5,000
o Assume up to 3 preliminary solutions.
• Develop Preliminary Solutions for Water Quality - $2,500 — $4,000
o Assume up to 6 BMP locations with preliminary design.
• Water Quality Modeling - $2,000 — $3,000
• Report - $5,000 - $7,000
o Summary report.
o Hydraulics and water quality summary.
o Preliminary cost estimate.
Estimated Cost: $19,500 - $28,000
Survey could be $10,000+, until they find out what control exists and until boundaries
are finalized difficult to prepare an estimate at this time.
The range is wide because there are a number of unknowns. Survey of the area will be
critical and hydraulic modeling will need to also be very detailed to best understand the
nuances of the drainage areas. It is understood that Big Marine Lake is a high priority
resource for the Watershed District and City. Therefore, water quality could become an
important component of the project. I recommend we assemble a group of
stakeholders and meet to finalize a scope. If this meeting determines that the City
should simply address the flooding conditions and a report is not necessary, than the
costs could be even lower.
Attached is the last study we completed in Forest Lake for Rice Creek Watershed
District/Clear Lake Association as an example.
BOLTON
Real People. Real Solutions.
Submitted by:
Bolton & Menk, Inc.
2035 County Rd D East
Maplewood, MN 55109
P: 651-704-9970
F: 651-704-9971
W"'hfA RCW D
RICE CREEK WATERSHED DISTRICT
Forest Lake
+S GOOD AS IT SOUNDS
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Table of Contents
EXECUTIVE SUMMARY..................................................................................................................... 1
I. BACKGROUND INFORMATION...............................................................................................2
II. 11TH AVENUE WATERSHED DESCRIPTION.............................................................................. 3
III. HYDRAULIC MODELING.......................................................................................................... 5
IV. PRELIMINARY WATER QUALITY BEST MANAGEMENT PRACTICES ......................................... 5
V. PARTNERSHIPS AND FUNDING.............................................................................................12
VI. RECOMMENDATIONS...........................................................................................................12
Table 1: Summary of water quality results at 11th Avenue Sampling Location (Clear Lake
Diagnostic Study and Management Plan, RCWD, Feb 2012, Pg. 2-9) .............................................. 2
Table 2: Summary of land use in 11th Avenue watershed.............................................................. 3
Table 3: Summary of existing conditions hydraulics....................................................................... 5
Table 4: Summary stormwater reuse of irrigation results.............................................................. 8
Table 5: Summary of water quality for irrigation........................................................................... 8
Table 6: Opinion of probable costs for stormwater capture and reuse for irrigation .................... 9
Table 7: Summary of water quality improvements for IESF.........................................................10
Table 8: Opinion of probable costs for IESF..................................................................................10
Exhibits
Exhibit 1: Residential rain gardens target areas. (Clear Lake Diagnostic Study and Management
Plan, RCWD, Feb 2012, Figure 5.2, Pg. 5-6)..................................................................................... 3
Exhibit 2: Exhibit from 2013 showing current extents of irrigated area.........................................4
Exhibit 3: Floating island technology. Photo courtesy of BioHaven Floating Wetlands.
(http://midwestfloatingisland.com/technology/).........................................................................11
Appendix
Appendix A: Figures
Appendix B: Met Council Reuse Calculator Output
Appendix C: MIDS Calculator Output
Prepared by: Bolton & Menk, Inc. Table of Contents
Clear Lake Water Quality Improvements I N13114978
EXECUTIVE SUMMARY
In February, 2012, RCWD released the Clear Lake Diagnostic Study and Management Plan that identified
the primary water quality concerns for Clear Lake and presented an implementation plan for meeting the
targeted water quality goals. The 11' Avenue SW culvert crossing was targeted as a sampling location in
the Diagnostic Study and was identified as having moderately high total phosphorus (TP) concentrations
and low total suspended solids (TSS) concentrations. Several best management practices (BMPs) were
identified to help meet the annual 140 pound phosphorus reduction goal.
This feasibility report is intended to serve as a foundation for future funding opportunities and grant
pursuits and should be considered an extension of the Clear Lake Diagnostic Study. A comprehensive
hydraulic model of the I I' Avenue SW drainage area was developed to understand the total inflow to the
MnDNR Public Water Wetland area and several stormwater ponds throughout the watershed. The
resulting hydrologic and hydraulic analyses served as a foundation for BMP placement.
The feasibility report identified several stormwater management and water quality improvement practices
to improve water quality to Clear Lake. These include the following.
• Stormwater capture and reuse for irrigation on the Elementary School site.
• Perched Iron enhanced sand filter (IESF) in conjunction with the stormwater reuse system.
• IESFs in strategic locations.
• Residential rain gardens.
• Modifications to the stormwater pond located just north of 11' Avenue SW.
The stormwater collection and reuse for irrigation project provides the most benefit in terms of
stormwater volume reduction, TP removal and groundwater savings. IESF filters strategically located
will also provide some beneficial TP removal, but offer additional challenges in terms of soils conditions,
depth to ground water and available space. RCWD identified rain gardens in the residential areas as an
option in the Clear Lake Diagnostic Study. Finally, the existing stormwater pond that currently serves the
apartment complex north of I I' Avenue SW may have an opportunity for improvement during the
reconstruction of 11' Avenue in 2022.
This feasibility study identifies viable opportunities for TP reduction into Clear Lake and summarizes
potential TP reductions and opinions of probable cost for a stormwater collection and reuse for irrigation
and IESFs. Residential rain gardens were summarized in the Clear Lake Diagnostic Study and
improvements to the 111' Avenue apartment pond will be further analyzed with future projects. The
summary table below identifies potential water quality improvements and opinions of probable costs for
the irrigation project and IESF.
Prepared by: Bolton & Menk, Inc.
Clear Lake Water Quality Improvements I N13114978
EXECUTIVE SUMMARY
Page 1
I. BACKGROUND INFORMATION
In February, 2012, RCWD released the Clear Lake Diagnostic Study and Management Plan that
identified the primary water quality concerns for Clear Lake and presented an implementation plan
for meeting the targeted water quality goals. The Executive Summary from the report described
nutrient loading in Clear Lake as follows.
"Nutrient loading to Clear Lake is predominantly from the watershed representing almost 75%
of the phosphorus load to the lake. Internal nutrient loading is less than 20% of the phosphorus
load with the remaining load coming from direct atmospheric deposition. In the RCWD
Watershed Management Plan (Houston Engineering, 2010), Clear Lake was identified as a Tier
I lake. Tier I lakes are defined in the Plan as routinely providing recreational opportunities,
and represent a high quality resource for fish and wildlife. RCWD has set relatively higher goals
for water quality in Tier I lakes; for deep lakes, the average total phosphorus concentration
goal is 31,ug/L as a summer average. Based on the response model meeting the 31,ug/L summer
average requires a 140 pound reduction in phosphorus loading. "
The 11' Avenue culvert crossing was targeted as a sampling location in the Diagnostic Study and
was identified as having moderately high total phosphorus (TP) concentrations and low total
suspended solids (TSS) concentrations. The average water quality results are summarized in Table
1 below.
Table]: Summary of water quality results at 11th Avenue Sampling Location (Clear Lake Diagnostic Study and Management
Plan, RCWD, Feb 2012, Pg. 2-9)
The Clear Lake Diagnostic Study identified a summer average phosphorus concentration goal of 31
µg/L, or an annual reduction of 140 pounds. This goal can be achieved by targeting the highest
contributing areas and assessing projects that would maximize reductions in phosphorus loading.
The Diagnostic Study identified projects in the 11th Avenue drainage area that included rain
gardens in the residential areas that would remove approximately 39 pounds per year phosphorus
reduction. Exhibit 1 is an excerpt from the Diagnostic Study that showed the neighborhoods where
rain gardens were targeted. Other recommended treatment methods for Clear Lake were generally
proposed outside of the 11th Avenue watershed.
The City of Forest Lake, in conjunction with RCWD and BWSR, has begun constructing water
quality improvement projects at City Hall and the Forest Lake High School that will greatly
contribute to the 140 pounds of phosphorus per year reduction goal. This study is intended to
develop:
Concept level project opportunities in the 11' Avenue watershed.
• Total Phosphorus (TP) load reduction estimates.
• Preliminary cost estimates for the improvements.
Prepared by: Bolton & Menk, Inc.
Clear Lake Water Quality Improvements I N13114978
BACKGROUND INFORMATION
Page 2
Exhibit 1: Residential rain gardens target areas. (Clear Lake Diagnostic Study and Management Plan, RCWD, Feb 2012, Figure
5.2, Pg. 5-6)
II. 11TH AVENUE WATERSHED DESCRIPTION
The l lt' Avenue watershed discharges approximately 122 acres of mixed land use into the north
side of Clear Lake. Table 2 describes the contributing land uses in the watershed. Soils are
primarily Hydraulic Soils Group B and B/D with low to moderate infiltration capacity. Drainage
patterns are generally north to south through city storm sewer system, stormwater management
ponds, wetland areas and open channels. Figure 1 describes the 11`' Avenue drainage area.
Table 2: Summary of land use in 11 th Avenue watershed.
�1Land Use
_t
Area (ac)
Assumed ',
Impervious
Impervious
Area (ac)
Single Family Residential
20.0
38%
7.6
Multi -Family Residential
17.1
65%
11.1
Institutional
66.5
25%
16.6
Retail/Commercial
9.2
85%
7.8
Preserve/Open Space
4.4
15%
0.7
Open Water
4.7
0%
0
Total
122
36%
44
Prepared by: Bolton & Menk, Inc. 11TH AVENUE WATERSHED DESCRIPTION
Clear Lake Water Quality Improvements I N13114978 Page 3
Forest Lake Area Schools irrigate Schumacher Baseball Field (southeast quadrant of 3' Avenue
SW and 8' Street SW) and the track area just south of the baseball field. Exhibit 2 is an aerial
photo of the site from 2013 that shows the current sparse irrigation coverage.
Exhibit 2: Exhibit from 2013 showing current extents of irrigated area.
As seen in Figure 1, the l lt' Avenue watershed contains storm sewer conveyance, wetland areas,
open water wetlands/lakes and stormwater ponds. Much of the developed portions of the
watershed, including nearly all of the impervious surface, is discharged through a dedicated
stormwater facility prior to discharging into the Unnamed Public Water (PWI) lake or the large
wetland complex on the south side of the School property. The primary surface storage and
conveyance features include the following.
• Stormwater Pond 1
• Stormwater Pond 2
• DNR Public Water Wetland
• Wetland Complex
• Open Ditch
• Stormwater Pond 3
Drainage continues through an open channel section between the multi -family residential area and
Prepared by: Bolton & Menk, Inc. 11TH AVENUE WATERSHED DESCRIPTION
Clear Lake Water Quality Improvements I N13114978 Page 4
V'
area of 36.4 acres and a total impervious area of 18.2 acres. Stormwater Pond 1 and the DNR
Public Water Wetland collect the rest of the storm water, with drainage areas of 13.5 acres
and 27.5 acres, respectively. Much of the runoff to Stormwater Ponds 2 and 3 are a result of
runoff from the elementary school property itself. This project envisions utilizing the
Elementary Ponds for collection and storage of stormwater for ball field irrigation. A total of
8 scenarios were addressed that include combinations of the following.
• Utilize Stormwater Pond 1 and the DNR Public Water Wetland for potential
stormwater storage and irrigation. These two basins are hydraulically connected via
an overland flow channel.
• Utilize all three potential irrigation sources including Stormwater Pond 1, Stormwater
Pond 2, and the DNR Public Water Wetland. It is assumed that the ponds included in
each scenario would be hydraulically connected with each other such that the storage
volume in the DNR Public Waters Wetland would be available for stormwater
flowing into either of the other two ponds.
• Assumptions for 0.5" and 1" per week irrigation demand.
• Irrigation areas of 11.4 acres (current irrigation use) and 18.0 acres (maximum
potential irrigated area).
Table 4 indicates the approximate existing pond storage volumes available for irrigation
water supply. The entire pond volume is not available for irrigation due to physical limits for
draining the pond and aesthetic concerns. These volumes were used to determine the
irrigation potential depending on the ponds utilized and targeted irrigation rate. Table 4 also
illustrates the percentage of weeks that the stormwater reuse would be able to supply enough
water to meet the demand of the specified irrigation area. Each pond individually is not
capable of meeting the current irrigation demand of 11.4 acres, but if all three ponds were
hydraulically connected, then there would be enough stormwater supply and storage to meet
and exceed the current irrigation demand of 11.4 acres.
1. Irrigated Areas
The 11.4 acre area shown in Figure 2 is currently irrigated. It is proposed to upgrade the
existing system to provide better irrigation coverage. If water appropriations allow,
additional irrigated acreage could be added to the south which would require additional
irrigation infrastructure. As much as 18 acres of turf grass could be irrigated if the
distribution system were expanded. It is proposed to utilize the existing irrigation system
water supply to supplement the stormwater supply during dry periods when water reuse is
restricted.
2. Required Irrigation System Elements
The storm water reuse systems will utilize existing surface water storage features to the
maximum extent practicable and new pump stations and piping to convey the reuse water
to the irrigation areas. The project will incorporate retrofits to the existing irrigation
system to expand the irrigated areas, as well as improve the performance of the current
system. Each pump station will include pumps and controls that will monitor flow and
pressure and adjust the pumping rate to meet the demand. The pump stations will also
include a treatment unit and self -flushing filter to provide water quality which allows
normal sprinkler system operation. The reuse water will be treated to address any fecal
coliform or other health concerns related to use of reuse water on the ball fields.
Prepared by: Bolton & Menk, Inc. PRELIMINARY WATER QUALITY BEST MANAGEMENT PRACTICES
Clear Lake Water Quality Improvements I N13114978 Page 6
Gate control valves are recommended to further extend the available storage volume for
irrigation between rain fall events. OptiRTC offers fully automated gate control valves
that are remotely connected to weather forecasting. During dry periods, stormwater
runoff will be stored in the preferred storage areas and gate controls will maximize the
quantity of water stored. If rainfall is in the forecast, the gates will open and restore the
flood capacity of the basins. Not only does this gate operation maximize irrigation
volume, it also extends the detention time and opportunity for sediment and phosphorus
to settle in the basins.
The existing irrigation system at the Elementary School uses a well to supply
groundwater. Therefore, that system does not include filters and other stormwater
treatment features that might be used for treating stormwater in the reuse system. The
reuse system pump stations will include a treatment unit with self -flushing filters to
provide sufficient water quality to allow normal sprinkler system operation. The reuse
water will be treated using a UV water treatment system to address any health concerns
related to human contact with the reuse water on the ball fields.
3. Water Appropriation Regulations
A water use (appropriation) permit is required from the Minnesota DNR for all users
withdrawing more than 10,000 gallons of water per day or 1 million gallons per year.
The 10,000 gallon threshold is relatively low, equating to 1/3 -inches per day over 1.1
acres. Minnesota State Statues also include the following language regarding dry
weather periods.
In order to safeguard water availability for natural environments and downstream
higher priority users, Minnesota law requires the DNR to limit consumptive
appropriations of surface water under certain low flow conditions. Should conditions
warrant, DNR Waters may suspend surface water appropriation permits as determined
by its Surface Water Appropriation Permit Issuance and Suspension Procedures.
Because stormwater may be scarce during dry periods, and because the Minnesota DNR
may limit appropriations of surface water during low flow conditions, another source of
irrigation water will also be needed for use in those times when stormwater supply is
insufficient to meet demand. We are assuming that the Elementary School site already
has an irrigation well or additional source of water that can be used as a backup supply to
the stormwater reuse system.
4. Ground water savings
Table 4 lists the percentage of annual irrigation goals achieved by the reuse of
stormwater, and the volumes of potable water "saved." The Met Council Stormwater
Reuse Guide, Water Balance Tool was used to evaluate the potential reuse systems. The
tool was used to determine the expected percentage of weeks per growing season where
the irrigation goals can be achieved through the stormwater reuse system. Based on the
Met Council Reuse Tool's 31 year period of rainfall records, the reuse systems will be
expected to provide sufficient storm water to meet irrigation goals of 0.5" and 1" per
week, with no supplemental water required, in as many weeks as possible during the May
through September irrigation seasons. Output from the Met Council Water Balance Tool
can be found in Appendix B.
Prepared by: Bolton & Menk, Inc. PRELIMINARY WATER QUALITY BEST MANAGEMENT PRACTICES
Clear Lake Water Quality Improvements I N13114978 Page 7
Table 4: Summary stormwater reuse of irrigation results.
5. Water Quality Improvements
The Minimal Impact Design Standards for enhancing stormwater management in
Minnesota (MIDS) Calculator was used to estimate the annual pollutant loads and
removals for each of the reuse projects. Table 5 lists the expected annual load reductions
of Total Phosphorus and Total Suspended Solids of the stormwater reuse systems. Each
project can be expected to remove pounds of phosphorus from the stormwater runoff
each year. These pollutant reductions singly or combined will provide demonstrated
water quality benefits to Clear Lake. Output from the MIDS calculator can be found in
Appendix C.
Table 5: Summary of water quality for irrigation.
rershed
mpervious
Irrigation
Pond
Storage
Available
Irrigation
Reuse
Efficiency (%
time with no
Scenario
rea
(Acres)
Area
(Acres)
Rate
(in./week)
for reuse
(ac -ft)
Area
(Acres)
supplemental
water needed)
Area
Rate
Particulate
P load
Dissolved
P load
Load
load
Scenario
(Acres)
(Acres)
(Acres)
(inJweek)
P load (lbs)
Reduction
(lbs)
P load
(lbs)
Reduction
(lbs)
Reduction
(lbs.)
Reduction
M
5. Water Quality Improvements
The Minimal Impact Design Standards for enhancing stormwater management in
Minnesota (MIDS) Calculator was used to estimate the annual pollutant loads and
removals for each of the reuse projects. Table 5 lists the expected annual load reductions
of Total Phosphorus and Total Suspended Solids of the stormwater reuse systems. Each
project can be expected to remove pounds of phosphorus from the stormwater runoff
each year. These pollutant reductions singly or combined will provide demonstrated
water quality benefits to Clear Lake. Output from the MIDS calculator can be found in
Appendix C.
Table 5: Summary of water quality for irrigation.
6. Opinion of Probable Cost
Table 6 summarizes the opinion of probable cost for each of the study sites. These
probable costs reflect 2017 prices and are based on the following research.
• Estimated costs from pipe, pump, irrigation system, and water treatment suppliers.
Prepared by: Bolton & Menk, Inc. PRELIMINARY WATER QUALITY BEST MANAGEMENT PRACTICES
Clear Lake Water Quality Improvements I N13114978 Page 8
Impervious
Irrigation
Irrigation
Annual
Annual
Particulate
Annual
Annual
Dissolved
Total P
Percent
Total P
Watershed
Area
Area
Area
Rate
Particulate
P load
Dissolved
P load
Load
load
Scenario
(Acres)
(Acres)
(Acres)
(inJweek)
P load (lbs)
Reduction
(lbs)
P load
(lbs)
Reduction
(lbs)
Reduction
(lbs.)
Reduction
M
6. Opinion of Probable Cost
Table 6 summarizes the opinion of probable cost for each of the study sites. These
probable costs reflect 2017 prices and are based on the following research.
• Estimated costs from pipe, pump, irrigation system, and water treatment suppliers.
Prepared by: Bolton & Menk, Inc. PRELIMINARY WATER QUALITY BEST MANAGEMENT PRACTICES
Clear Lake Water Quality Improvements I N13114978 Page 8
C'
DENR, March 22, 2012) recommended that an initial TN and TP removal "credit" of 5%
above the anticipated pond removal capacity is applicable. If the vegetation is harvested,
these percentage credits could become higher. Exhibit 3 is an example floating island
concept and the key features therein.
Current water quality capacity of Stormwater Pond 3 is unknown. The pond serves the
impervious area from the Village Apartment complex and is constructed online with the
DNR Public Water Wetland and City drainage ditch. Therefore, it is undersized from the
MCPA's design guidance perspective and high inflow rates likely suspends accumulated
sediment during rain fall events. Therefore, it is assumed that a floating wetland would
essentially treat up to 5% of the remaining inflow nutrient concentrations, at a maximum.
BIOHAVEN FLOATING WETLAND
terrestrial habitat creation
Y '
erosion control
aquatic habitat creation
water quality treatment
w R-LA.LW 2014
Exhibit 3: Floating island technology. Photo courtesy of BioHaven Floating Wetlands.
(http://midwesifloatingisland.conVtechnologyl)
2. Research Opportunities
R
Given the accessibility of the pond and known nutrient issues, a floating wetland at this
location may offer RCWD an opportunity for research, development and education.
Inflow and outflow sampling could provide a better idea of how these systems work as a
retrofit to existing stormwater ponds and potentially confirm the use as a viable BMP
throughout the district.
3. Floating Wetland Sizing and Opinion of Probable Cost
According to "Performance Evaluation of a Floating Treatment Wetland in an Urban
Catchment" (MDPI, Water Journal, 2016), a recommended wetland size range is
approximately 0.10% to 0.20% of the contributing watershed. Since the total watershed
area is approximately 122 acres and the stormwater pond is approximately 10,000 square
feet at the normal water level, the wetland would essentially consume the entire normal
water level footprint. Therefore, it is recommended that the floating wetland be sized for
the immediate drainage area entering the basin, or 10.0 acres. The recommended floating
wetland size is 430 square feet. The approximate cost of a floating wetland is $35/square
foot. The total approximate cost of the floating wetland is $15,000 to $20,000.
Prepared by: Bolton & Menk, Inc. PRELIMINARY WATER QUALITY BEST MANAGEMENT PRACTICES
Clear Lake Water Quality Improvements I N13114978 Page 11
4. Routine Maintenance
At a minimum, the stormwater pond could be excavated to remove the accumulated
sediment and restore it to its originally intended design capacity. Removing the
nutrients tied to the accumulated sediment also reduces the potential for suspension of
the "legacy" sediment during rainfall events.
5. Future 11' Avenue SW Improvements
11' Avenue SW is scheduled to be improved in 2022. In order to meet permitting
requirement at that time, Stormwater Pond 3 could be expanded, or other retrofits
considered. Therefore, it may be prudent to explore other treatment options associate
with the future roadway project.
D. Residential Rain Gardens
The Clear Lake Diagnostic Study identified residential rain gardens as an alternative
BMP program within the 11' Avenue SW watershed. An effective rain garden program
could remove up to 39 pounds of phosphorus per year. The City should consider
residential rain gardens associated with future roadway projects. Similar challenges to
IESF construction are likely with a rain garden program.
It is recommended that the City consider residential rain gardens or biofiltration features
as street reconstruction projects occur. Construction of the rain gardens could constitute
an improvement in water quality above and beyond minimum permitting requirements
and could establish a credit system for more challenging site conditions in the watershed.
Further, Urban Cost Share opportunities could be pursued to help meet the long term
goals of Clear Lake.
E. Drainage Ditch Connecting Wetland Complex and Stormwater Pond 3
Stormwater runoff is conveyed via open ditch from the wetland complex south to
Stormwater Pond 3. The City currently operates a drainage and utility easement along
the ditch. However, access to the ditch area for both construction and long term
maintenance is difficult. Therefore, it is not recommended that a high level water quality
BMP be constructed in this area. Instead, the City and Watershed should consider
maintenance of the ditch by removing accumulated scrub vegetation, garbage, sediment,
etc. from the ditch to ensure effective drainage.
V. PARTNERSHIPS AND FUNDING
Initial discussions have established the foundation for a partnership including Forest Lake Area
Schools, Rice Creek Watershed District, Clear Lake Association and the City of Forest Lake. Not
only are certain funding applications contingent on established partnerships, but they strengthen the
application. Further, multiple project partners reduces economic burden and encourages common
environmental benefit by all stake holders.
This feasibility report can be the basis for funding applications to the Board of Soil and Water
Resources (BWSR) Clean Water Fund program. Upon approval, an application for Projects and
Practices will be completed and submitted. The funding application cycle generally opens in July
and closes in August.
VI. RECOMMENDATIONS
Prepared by: Bolton & Menk, Inc.
Clear Lake Water Quality Improvements I N13114978
PARTNERSHIPS AND FUNDING
Page 12
We suggest that RCWD, Clear Lake Association, the City of Forest Lake and Forest Lake Area
Schools consider the stormwater reuse project and iron enhanced sand filtration outlined within this
report. In a previous analysis of all irrigation projects on the Forest Lake Area Schools properties,
the Elementary School site ranked best in terms of cost per annual volume irrigated. The following
recommendations should be considered as part of the long term planning effort for Clear Lake and
as an extension of the Clear Lake Diagnostic Study.
• The partnership should apply for grants to the BWSR Clean Water Fund. Operation and
Maintenance agreements should be discussed prior to the grant pursuit.
• The highest benefit project is the stormwater collection and reuse for irrigation on the
elementary school site.
• While smaller, isolated IESF features could have a cumulative and beneficial reduction in TP
loading to Clear Lake, it is recommended that a perched IESF be considered in conjunction
with the reuse project. Between events, excess stormwater not used for irrigation could be
pumped to the perched filter to offer additional TP removal.
• Residential rain gardens should be considered during future reconstruction projects in the
watershed. If the rain gardens provide stormwater treatment above and beyond the minimum
permitting requirements, the City should apply for RCWD Urban Cost Share dollars as projects
occur.
• The stormwater capture and reuse system will offer a significant benefit in terms of volume and
nutrient reduction to Clear Lake. Similarly, the stormwater inflow to Stormwater Pond 3 will
improve and should help with seasonal algae blooms. A floating wetland could be considered
to further improve nutrient uptake between rainfall events.
• Additional improvements to Stormwater Pond 3 are likely to occur with the future
reconstruction of I I' Avenue SW in 2022.
Prepared by: Bolton & Menk, Inc.
Clear Lake Water Quality Improvements I N13114978
RECOMMENDATIONS
Page 13