6. Scandia Community Water Study FINALH:\SCND\N13118583\2_Preliminary\C_Reports\Scandia Community Water Study Memo.docx
MEMORANDUM
Date: September 6, 2019
To: Adam Hawkinson, City of Scandia
From: Jacob Humburg, P.E.
Ryan Goodman, P.E.
Subject: Community Water Study – Fire Station Area
Introduction
This memo and its attachments are the product of the Community Water Study proposed in
February 2019. The purpose of this study was to break down the various components and costs
that would be associated with constructing a drinking water supply and distribution system to
serve the same area that was examined in the 2018 Community Drainfield Study. The 2018
study considered the area immediately surrounding the Scandia Fire Hall, the area immediately
to the south of the Fire Hall, across Hwy 97, and a potential new development to the east of the
Fire Hall and extending to the south side of Hwy 97. A figure is attached to this memo which
shows the areas described and a layout of the proposed system.
Explanation of Proposed System Sizing and Layout
Daily flows within the proposed system were calculated for each existing establishment and
property, as well as for the land area slated for potential future development. Attached to this
document is a breakdown of the various flow demands within the system and the calculations
used to determine average day, peak day, and peak hour flows. It was assumed that any future
development on land to the east of the Fire Hall would be categorized as a mix of commercial
and light industrial. The undeveloped land included approximately 7.7 acres located south and
27.9 acres north of Hwy 97. One third of the land was assumed to be light industrial, while the
other two thirds were assumed to be developed for commercial use. The total average day
demand for the system was conservatively calculated to be 75,000 gallons, the maximum day
Name: Scandia – Community Water Study – Fire Station Area
Date: September 6, 2019
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demand to be approximately 210,000 gallons (average of 150 gallons per minute), and the peak
hourly flow to be 200 gallons per minute.
Sizing of the water supply components of the system is based on the ability to meet the
maximum day demand. Per 10 States Standards, the maximum day demand must be met with
the largest supply well out of service. It was assumed that the existing 550-gallon per minute
well could supply the new water system, but would need to be refitted with a new pump to
handle the altered pumping head condition. In addition to this existing well, a new well would
need to be constructed to provide redundancy to the system. Based on the projected maximum
day demand of 150 gallons per minute, a 200-gallon per minute well was assumed. In this way,
the smallest well could not only meet maximum day demand, but peak hourly demand as well,
for a negligible difference in cost. For the purposes of this study it is assumed that the new well
would be drilled into the Jordan Aquifer, approximately 250 feet below grade. It should be noted
though, that constructing this new well and being permitted to pump the necessary flows could
encounter hurdles with the Department of Natural Resources (DNR), depending on how the new
well might affect the aquifer and other nearby resources. Many of these details could not be
further clarified until the well is already drilled. Likewise, for the existing well which is drilled
into the Mt. Simon-Hinckley Aquifer, it is unknown how much daily flow the DNR would
ultimately permit to be withdrawn from this well. Regardless, for the purposes of generating
cost estimates for this study, it was assumed that these two wells would be able to produce the
flow required by the new system.
Sizing for necessary storage within the system is more complicated than simply meeting the
average or peak day demands of the system. Especially for small communities, it is often fire
flow demands which dictate sizing, and this is the case for the proposed system in Scandia. Due
to Scandia’s topography, the best overall option for storage is an elevated tower, which serves
the additional purpose of providing pressure to the distribution system. Scandia’s 2019 Public
Protection Classification (PPC) report from the Insurance Services Office (ISO) specifies a Basic
Fire Flow of 3,000 gallons per minute and based on the International Code Council (ICC)
requirements the fire duration would be three hours. Taking into account the water supply
capacity (wells) described above, this would require storage of over 500,000 gallons. For a
community of Scandia’s size, this is not feasible. In addition to being prohibitively expensive to
Name: Scandia – Community Water Study – Fire Station Area
Date: September 6, 2019
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construct, a tower of this size would almost certainly have issues with freezing in the winter,
considering the low amount of water turnover that would be experienced on an average day.
Based on the 2019 ISO report, the City is not currently able to meet this 3,000-gallon per minute
demand anyway, so insurance ratings for existing or future businesses in Scandia would not
change from what they are currently.
The International Plumbing Code, as part of ICC, uses 1,500 gallons per minute for a duration of
two hours as the minimum fire flow required for buildings that are not family dwellings.
Because the 3,000-gallon per minute flow is not being designed for as part of this study, this
1,500-gallon per minute flow was used for sizing elevated storage. It was determined that a
tower with a capacity of approximately 175,000 gallons would be needed. Table 1, below,
summarizes how this number was obtained.
Table 1
Sizing of Proposed Elevated Storage for Scandia
Fire Demand (gpm)1,500
Peak Usage (gpm)+200
Total Coincident Demand =1,700
Supply (gpm)-700
Withdrawal from Storage (gpm)=1,000
Fire Flow Duration (minutes)× 120
Fire Fighting Storage (MG)=0.120
Equalizing Storage (25% of
Max. Day Demand, MG)+0.053
Total Storage Required (MG)=0.173
Simply for comparison purposes, the sizing of the water supply and storage system would allow
for 190 residences to be served in place of the proposed commercial/light industrial
development, assuming three persons per household and 100 gallons per capita daily water use.
For water treatment within the new system construction of a new well house was assumed, which
would meter and add chemical to water produced by both wells prior to it entering the
distribution system. This structure would be of concrete masonry unit and contain three rooms:
one for chemical addition and metering, one for fluoride chemical storage, and one for chlorine.
Name: Scandia – Community Water Study – Fire Station Area
Date: September 6, 2019
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The basic layout of the proposed distribution system is illustrated in Figure 1 at the end of this
memo. All water mains within the system were sized as 8-inch diameter, to retain the ability to
supply greater fire flows in the future, should the proposed system be expanded or other
circumstances change. All of the main water supply infrastructure, including the new well, well
house, and water tower were positioned on the Fire Hall property. The reasoning behind this was
the location of the existing well, the availability of land to the City, and the property’s central
location within the proposed distribution system. All costs for the distribution system, as well as
the proposed wells, well house, and water tower are detailed in the Engineer’s Cost Opinion
attached to this memo.
Engineer's Opinion of Cost
Scandia Water Study
City of Scandia, MN
Date: 09/05/19
Part 1:
1.1 REPLACE EXISTING 550 GPM PUMP & PITLESS UNIT 1 LUMP SUM $80,000.00 $80,000.00
2.1 DRILL NEW WELL, INSTALL 200 GPM PUMP & PITLESS UNIT 1 LUMP SUM $380,000.00 $380,000.00
3.1 NEW WELL HOUSE 1 LUMP SUM $550,000.00 $550,000.00
4.1 175000 GALLON STEEL ELEVATED STORAGE TOWER 1 LUMP SUM $1,200,000.00 $1,200,000.00
Part 1 Total:$2,210,000.00
Part 2:
1.2 MOBILIZATION 1 LUMP SUMP $20,000.00 $20,000.00
2.2 CLEARING AND GRUBBING 1.3 ACRE $10,000.00 $13,000.00
3.2 SAWING BITUMINOUS PAVEMENT (FULL DEPTH)1200 LIN FT $3.00 $3,600.00
4.2 REMOVE BITUMINOUS PAVEMENT 1350 SQ YD $5.00 $6,750.00
5.2 SALVAGE AND REINSTALL TRAFFIC SIGN 2 EACH $200.00 $400.00
6.2 SALVAGE, STOCKPILE, AND RESPREAD TOPSOIL 1 LUMP SUM $15,000.00 $15,000.00
7.2 SALVAGE, STOCKPILE, AND REINSTALL AGGREGATE BASE (EV)450 CU YD $18.00 $8,100.00
8.2 SUBGRADE EXCAVATION (EV)100 CU YD $17.00 $1,700.00
9.2 AGGREGATE BASE 800 TON $18.00 $14,400.00
10.2 STREET SWEEPER (WITH PICKUP BROOM)20 HOUR $150.00 $3,000.00
11.2 BITUMINOUS MATERIAL FOR TACK COAT 100 GAL $3.50 $350.00
12.2 TYPE SP 9.5 WEARING COURSE MIXTURE (3,B)400 TON $85.00 $34,000.00
13.2 IMPROVED PIPE FOUNDATION 1000 LIN FT $6.00 $6,000.00
14.2 8" PVC, WATER MAIN, C900 DR-18 2400 LIN FT $45.00 $108,000.00
15.2 6" PVC, WATER MAIN, C900 DR-18 300 LIN FT $40.00 $12,000.00
16.2 24" STEEL CASING 125 LIN FT $225.00 $28,125.00
17.2 8" GATE VALVE AND BOX 3 EACH $2,500.00 $7,500.00
18.2 6" GATE VALVE AND BOX 12 EACH $2,100.00 $25,200.00
19.2 DUCTILE IRON FITTINGS 2200 EACH $10.00 $22,000.00
20.2 HYDRANT 4 EACH $3,500.00 $14,000.00
21.2 1" WATER SERVICE 250 LIN FT $40.00 $10,000.00
22.2 1" CORPORATION STOP 4 EACH $700.00 $2,800.00
23.2 1" CURB STOP 4 EACH $800.00 $3,200.00
24.2 TRAFFIC CONTROL 1 LUMP SUMP $10,000.00 $10,000.00
25.2 STABILIZED CONSTRUCTION EXIT 1 LUMP SUM $3,500.00 $3,500.00
26.2 SEDIMENT CONTROL LOG TYPE STRAW 300 LIN FT $2.50 $750.00
27.2 SILT FENCE, TYPE MS 1000 LIN FT $2.00 $2,000.00
28.2 COMMON TOPSOIL BORROW (LV)300 CU YD $33.00 $9,900.00
29.2 SEED (MNDOT MIX 25-151), HYDRAULIC STABILIZED FIBER MATRIX, AND FERTILIZER TYPE 33.5 ACRE $5,000.00 $17,500.00
Part 2:$402,775.00
Total AmountItem No.Item Estimated
Quantity Unit Unit Price
9/6/2019, 1:12 PM
Engineer's Opinion of Cost
Bolton & Menk, Inc.Page 1 of 3
Engineer's Opinion of Cost
Scandia Water Study
City of Scandia, MN
Date: 09/05/19
Total AmountItem No.Item Estimated
Quantity Unit Unit Price
Part 3:
1.3 MOBILIZATION 1 LUMP SUMP $11,000.00 $11,000.00
2.3 CLEARING AND GRUBBING 2.3 ACRE $10,000.00 $23,000.00
3.3 SALVAGE, STOCKPILE, AND RESPREAD TOPSOIL 1 LUMP SUM $15,000.00 $15,000.00
4.3 STREET SWEEPER (WITH PICKUP BROOM)20 HOUR $150.00 $3,000.00
5.3 TYPE SP 9.5 WEARING COURSE MIXTURE (3,B)100 TON $100.00 $10,000.00
5.1 IMPROVED PIPE FOUNDATION 500 LIN FT $6.00 $3,000.00
6.1 8" PVC, WATER MAIN, C900 DR-18 1650 LIN FT $45.00 $74,250.00
7.1 6" PVC, WATER MAIN, C900 DR-18 150 LIN FT $40.00 $6,000.00
8.1 8" GATE VALVE AND BOX 3 EACH $2,500.00 $7,500.00
9.1 6" GATE VALVE AND BOX 3 EACH $2,100.00 $6,300.00
10.1 DUCTILE IRON FITTINGS 1500 EACH $10.00 $15,000.00
11.1 HYDRANT 1 EACH $3,500.00 $3,500.00
12.1 1" WATER SERVICE 100 LIN FT $40.00 $4,000.00
13.1 1" CORPORATION STOP 2 EACH $700.00 $1,400.00
14.1 1" CURB STOP 2 EACH $800.00 $1,600.00
15.1 TRAFFIC CONTROL 1 LUMP SUMP $3,000.00 $3,000.00
16.1 STABILIZED CONSTRUCTION EXIT 1 LUMP SUM $3,500.00 $3,500.00
17.1 SEDIMENT CONTROL LOG TYPE STRAW 100 LIN FT $2.50 $250.00
18.1 SILT FENCE, TYPE MS 200 LIN FT $2.00 $400.00
19.1 COMMON TOPSOIL BORROW (LV)150 CU YD $33.00 $4,950.00
20.1 SEED (MNDOT MIX 25-151), HYDRAULIC STABILIZED FIBER MATRIX, AND FERTILIZER TYPE 33 ACRE $5,000.00 $15,000.00
Part 3 Total:$211,650.00
9/6/2019, 1:12 PM
Engineer's Opinion of Cost
Bolton & Menk, Inc.Page 2 of 3
Engineer's Opinion of Cost
Scandia Water Study
City of Scandia, MN
Date: 09/05/19
Total AmountItem No.Item Estimated
Quantity Unit Unit Price
Part 4:
1.4 MOBILIZATION 1 LUMP SUMP $7,000.00 $7,000.00
2.4 SALVAGE, STOCKPILE, AND RESPREAD TOPSOIL 1 LUMP SUM $5,000.00 $5,000.00
3.4 STREET SWEEPER (WITH PICKUP BROOM)20 HOUR $150.00 $3,000.00
4.4 IMPROVED PIPE FOUNDATION 600 LIN FT $6.00 $3,600.00
5.4 8" PVC, WATER MAIN, C900 DR-18 1300 LIN FT $45.00 $58,500.00
6.4 6" PVC, WATER MAIN, C900 DR-18 150 LIN FT $40.00 $6,000.00
5.4 8" GATE VALVE AND BOX 2 EACH $2,500.00 $5,000.00
6.4 6" GATE VALVE AND BOX 3 EACH $2,100.00 $6,300.00
7.4 DUCTILE IRON FITTINGS 1500 EACH $10.00 $15,000.00
8.4 HYDRANT 1 EACH $3,500.00 $3,500.00
9.4 1" WATER SERVICE 100 LIN FT $40.00 $4,000.00
10.4 1" CORPORATION STOP 2 EACH $700.00 $1,400.00
11.4 1" CURB STOP 2 EACH $800.00 $1,600.00
12.4 TRAFFIC CONTROL 1 LUMP SUMP $2,000.00 $2,000.00
13.4 STRUCTURE MARKER SIGN PER DETAIL 505 3 EACH $50.00 $150.00
14.4 STABILIZED CONSTRUCTION EXIT 1 LUMP SUM $3,500.00 $3,500.00
15.4 SEDIMENT CONTROL LOG TYPE STRAW 100 LIN FT $2.50 $250.00
16.4 SILT FENCE, TYPE MS 200 LIN FT $2.00 $400.00
17.4 SEED (MNDOT MIX 25-151), HYDRAULIC STABILIZED FIBER MATRIX, AND FERTILIZER TYPE 32 ACRE $5,000.00 $10,000.00
Part 4 Total:$136,200.00
Part 1-4 Total:$2,960,625.00
9/6/2019, 1:12 PM
Engineer's Opinion of Cost
Bolton & Menk, Inc.Page 3 of 3
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PART 2
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PART 4
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H:\SCND\N13118583\CAD\C3D\Water System-Servce Area Figure 1 8.5x11.dwg 9/6/2019 4:24:07 PMCommunity Water Study
City of Scandia, MN
Potential Water System Layout
September 2019
R
FEETSCALE
0 200 400
FLOW ESTIMATIONS FROM EXISTING & FUTURE SOURCES
Step 1: South of Hwy 97 &
Existing Establishments
Scandia Auto
(5 employees)(49 gal/cap/day*) = 245 gpd
Am-Tec Designs, Inc.
(8 employees)(194 gal/cap/day*) = 1,552 gpd
Scandia Self Storage
0 gpd
PN Products
(8 employees)(119 gal/cap/day*) = 952 gpd
House S of PN Products
(3 people)(100 gal/cap/day*) = 300 gpd
Landscaping Business(?) E of PN
(3 employees)(90 gal/cap/day*) = 270 gpd
Chiko’s Restaurant (currently closed)
(18 bar seats + 45 table seats + 24 booth seats =
90 seats
(90 seats)(40 gpd/seat*) = 3,600 gpd
Scandia Clinic
(8 employees)(90 gal/cap/day*) = 720 gpd
Other Businesses West of Chiko’s:
(12 employees)(90 gal/cap/day*) = 1,080 gpd
Bank of Marine:
(5 employees)(62 gal/cap/day*) = 310 gpd
Tobacco Store
(2 employees)(70 gal/cap/day*) = 140 gpd
Liquor Store
(2 employees)(100 gal/cap/day*) = 200 gpd
Post Office
(4 employees)(5 gal/cap/day*) = 20 gpd
Stores W of Post Office
(5 employees)(90 gal/cap/day*) = 450 gpd
Scandia Pizzeria
(5 employees)(156 gal/cap/day*) = 780 gpd
Prairie Restorations, Inc.
(10 employees)(90 gal/cap/day*) = 900 gpd
Scandia Fire/Public Works
(5 employees)(50 gal/cap/day*) = 250 gpd
(3 beds)(100 gpd/bed*) = 300 gpd
Gas Station
(1,500 gpd wastewater)(1.5) = 2,250 gpd
Scandia Creamery
(1,850 gpd wastewater)(1.5) = 2,775 gpd
“Shop” South of Creamery
(2 employees)(50 gal/cap/day*) = 100 gpd
Upholstery Specialties
(3 employees)(36 gal/cap/day*) = 108 gpd
Undeveloped Land
Undeveloped land use assumed to be 2/3 retail
commercial and 1/3 light industrial, based on
ratios from sanitary sewer study
(7.7 acres)(2,040 gal/acre/day†)(0.667)(0.85) ≈
8,900 gpd
(7.7 acres)(1,620 gal/acre/day†)(0.333)(0.85) ≈
3,500 gpd
TOTAL FROM EXISTING & SOURCES SOUTH OF
HWY 97 ≈ 30,000 gpd
*Basis is Water Works Engineering textbook,
with typical daily flowrates for various
residences and establishments
†Basis is AWWA Hydraulic Design Handbook,
average values were lowered by 15% due to
higher per acre water use in western states, on
which values in book are based (Herman’s
suggestion)
Step 2: Proposed Development North of Hwy 97
For the first round of estimates, it is assumed that all new development north of Hwy 97 will be 2/3
retail commercial use and 1/3 light industrial use. Per the previous sanitary sewer study, it is estimated
that 9 acres of the proposed area to be developed will be used for a new drainfield system, and so will
not generate drinking water needs.
Commercial Flow:
(0.667)(27.9 acres)(2,040 gal/acre/day†)(0.85) = 32,300 gpd
Light Industrial Flow:
(0.333)(27.9 acres)(1,620 gal/acre/day†)(0.85) = 12,800 gpd
TOTAL FROM FUTURE SOURCES N OF HWY 97 ≈ 45,000 gpd
Step 3: Total Flows
Total flows from both current and future development = 30,000 gpd + 45,000 gpd ≈ 75,000 gpd
Maximum Day Flow = (75,000 gpd)(2.8‡) ≈ 210,000 gpd ≈ 150 gpm
Peak Hourly Flow = (75,000 gpd)(4.0‡) ≈ 300,000 gpd ≈ 200 gpm
‡Basis of peaking factors is AWWA Hydraulic Design Handbook and the values chosen are on the high
end of the offered range because the system being considered is very small in scale and typically the
smaller the system, the higher the peak flows are likely to be.
Step 4: Ability of Proposed Infrastructure to Serve Future Residential
Development
Average Daily Flow from Undeveloped Properties = 45,000 + 8,900 + 3,500 = 57,400 gpd
Flow Per Household = (3 cap/household)(100 gal/cap/day) = 300 gpd
Equivalent Households Served = 57,400/300 = 190