HomeMy WebLinkAbout4B Water System Plan Chapter of the 2040 Comprehensive Plan Update PC Report
Phone 952.447.9800 / Fax 952.447.4245 / www.cityofpriorlake.com
4646 Dakota Street SE
Prior Lake, MN 55372
PLANNING COMMISSION AGENDA REPORT
MEETING DATE: FEBRUARY 25, 2019
AGENDA #: 4B
PREPARED BY: JASON WEDEL, PUBLIC WORKS DIRECTOR/CITY ENGINEER
PRESENTED BY: JASON WEDEL
AGENDA ITEM:
PUBLIC HEARING TO CONSIDER RECOMMENDING APPROVAL OF A
RESOLUTION APPROVING THE WATER SYSTEM PLAN CHAPTER OF THE
CITY’S 2040 COMPREHENSIVE PLAN UPDATE
DISCUSSION: Introduction
The City is in the process of updating the 2040 Comprehensive Plan. The
Comprehensive Plan is a compilation of policy statements, goals, standards and
maps for guiding the physical, social and economic development, both private and
public, of the City of Prior Lake. Included in the Comprehensive Plan is a Water
System Plan Chapter.
Subsection 1108.804 of Prior Lake City Code states, the Planning Commission shall
review all requests for an amendment to the Comprehensive Plan or the
Comprehensive Plan Land Use Map at a public hearing and shall report its findings
and recommendations to the City Council.
History
The purpose of the Water System Plan is to evaluate and update the City’s water
system plan. This plan evaluates future design considerations with regards to water
system planning and infrastructure as well as current and future water demands.
The existing facilities and infrastructure are reviewed as well as future improvements
are analyzed to determine how future development will impact average day and
maximum day pressures along with maximum day fire flows based on the City’s
future land use planning.
Current Circumstances
The City currently meets its water needs using seven (7) municipal wells and
purchasing water from the Shakopee Mdewakanton Sioux Community (SMSC).
The Water System Plan looks at the City’s future land use as well as the population
projections to determine what additional improvements will be necessary to serve
the City and meet all the various demands.
The primary demands that are analyzed are the average day demand, the maximum
day demand, storage and fire flow. Utilizing the proposed land use map and the
current Met Council population projections for Prior Lake, a model was created to
determine the future improvements that will be necessary to meet the City’s future
demands.
The results of the updated Water System Plan indicate that the City is well prepared
for future development. No additional wells will be necessary to meet the City’s
long-term water needs. The recent agreement between the City and the SMSC and
construction of a joint water treatment plant is a key component to meeting the future
water needs of the City. That agreement provides 1.5 Million Gallons of water per
Day (MGD) to the City in perpetuity. The City does have the ability to add one more
well to supply water to the City’s existing water treatment plant in the event it
becomes more efficient to do so.
There is a need to continue the implementation of the City’s trunk watermain
infrastructure into the undeveloped portions of the City. These improvements
consist of oversized watermains and are typically constructed as property develops.
They are funded through the collection of trunk water fees as part of the
development contracts the City enters into with developers. This combination of
water supply and trunk watermain infrastructure will allow the City to meet the long-
term average day and maximum day demands.
The Water System Plan also confirmed that the City has sufficient existing storage
to meet all future demands. It is recommended that the City have enough storage
to meet or exceed the average day demand. At full build out, including the portions
of Spring Lake Township that are included the Orderly Annexation Agreement, the
City’s existing storage is sufficient to exceed the future average day demand. This
is accomplished through the storage that is currently available at both of the City’s
water towers as well as the below ground storage at the water treatment plant.
Fire flow is the final demand that was reviewed as part of the Water System Plan
Update. When a fire occurs, the use of water by the fire department in that location
can be very taxing on the overall water system. It is important to not only supply the
amount of water that is needed to extinguish the fire, but it is also important that the
high fire flows do not result in the creation of a negative water pressure on adjacent
properties which could result in contamination of the system. The results of the
model indicate that the City’s system will meet the fire flow requirements if the trunk
watermain infrastructure is completely as proposed.
Overall, the City of Prior Lake is well situated to meet the water needs of the
community both now and into the future.
ISSUES: One area that is part of the Water System Plan is a discussion on water
conservation. The City currently has a two-tiered billing rate for water consumption.
The objective of the tiered billing rate is to charge a lower rate for water used to
meet daily needs such as drinking, bathing, and doing laundry. The higher tier is
for water use associated with washing cars, filling swimming pools, and irrigation.
The maximum day demand is over three times the amount that is used on an
average day and it is primarily due to irrigation. The City currently charges $4.81
per 1,000 gallons for the first 25,000 gallons and $6.63 per 1,000 gallons for
anything above 25,000 gallons.
It is anticipated that the City will initiate a utility rate study in the next year or two to
evaluate the existing tiered rates to determine if they are accomplishing the goal of
reducing the maximum day demand. The study would also look at the possibility of
adding a third tier or other options for encouraging water conservation.
ALTERNATIVES: 1. Motion and a second to recommend the City Council approve a resolution
approving the Water System Plan.
2. Motion and a second to table or continue discussion of the item for a specific
purpose as directed by the Planning Commission.
RECOMMENDED
MOTION:
ATTACHMENT:
Alternative #1
1. Water System Plan Update
June 2018
Water System Plan Update
Prior Lake, Minnesota
Bolton & Menk Project No. T21.113723
Submitted by:
Bolton & Menk, Inc.
12224 Nicollet Ave
Burnsville, MN 55337
P: 507-625-4171
F: 507-625-4177
Prepared by: Bolton & Menk, Inc. Certification
Water System Plan Update | T21.113723
Certification
Water System Plan Update
for
Prior Lake, Minnesota
BMI Project No.: T21.113723
June 2018
I hereby certify that this plan, specification or report was
prepared by me or under my direct supervision, and that I
am a duly Licensed Professional Engineer under the laws of
the State of Minnesota.
By:
Seth A. Peterson, P.E.
License No. 26468
Date: June 20, 2018
Prepared by: Bolton & Menk, Inc. Table of Contents
Water System Plan Update ǀ T21.113723
Table of Contents
I. EXECUTIVE SUMMARY ........................................................................................................... 1
II. WATER SYSTEM DESIGN CRITERIA ......................................................................................... 3
GENERAL ...................................................................................................................... 3
DESIGN PERIOD ............................................................................................................ 3
PLANNING AREA .......................................................................................................... 3
POPULATION AND WATER USE ................................................................................... 4
DISTRIBUTION SYSTEM REQUIREMENTS .................................................................. 11
III. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE ............................................ 13
GENERAL .................................................................................................................... 13
WATER SUPPLY .......................................................................................................... 13
WATER TREATMENT FACILITIES ................................................................................ 17
WATER DISTRIBUTION SYSTEM ................................................................................. 17
WATER DISTRIBUTION FACILITIES ............................................................................. 22
WATER STORAGE FACILITIES ..................................................................................... 22
WATER QUALITY ........................................................................................................ 28
IV. WATER CONSERVATION ....................................................................................................... 31
GENERAL .................................................................................................................... 31
REDUCING USE ........................................................................................................... 31
REDUCING PEAK DEMANDS ...................................................................................... 33
WATER RATES ............................................................................................................ 33
WATER LOSS ............................................................................................................... 34
V. RECOMMENDED FUTURE IMPROVEMENTS ......................................................................... 36
GENERAL .................................................................................................................... 36
WATER SUPPLY .......................................................................................................... 36
WATER TREATMENT FACILITIES ................................................................................ 36
WATER DISTRIBUTION SYSTEM ................................................................................. 37
WATER DISTRIBUTION FACILITIES ............................................................................. 46
WATER STORAGE FACILITIES ..................................................................................... 46
VI. ECONOMIC ANALYSIS ........................................................................................................... 48
GENERAL .................................................................................................................... 48
CAPITAL IMPROVEMENT PLAN AND COST ESTIMATES ............................................ 49
FUNDING .................................................................................................................... 50
Prepared by: Bolton & Menk, Inc. Table of Contents
Water System Plan Update ǀ T21.113723
Figures
Figure 2.1: Average and Maximum Day Demand Trends ................................................................ 6
Figure 2.2: Prior Lake Water Use by Category ................................................................................. 7
Figure 3.1: Existing Water Distribution System ............................................................................ 14
Figure 3.2: Existing Average Daily Pressure ................................................................................... 20
Figure 3.3: Existing Maximum Day Pressure .................................................................................. 21
Figure 3.4: Existing Maximum Day Fire Flow ................................................................................. 25
Figure 3.5: Existing Average Day Hydraulic Grade Line ................................................................. 26
Figure 3.6: Existing Maximum Day Hydraulic Grade Line .............................................................. 27
Figure 5.1: Anticipated Water Distribution System ....................................................................... 40
Figure 5.2: Projected Average Daily Pressure ................................................................................ 41
Figure 5.3: Projected Maximum Daily Pressure ............................................................................. 42
Figure 5.4: Projected Maximum Day Fire Flow .............................................................................. 43
Figure 5.5: Projected Average Day Hydraulic Grade Line .............................................................. 44
Figure 5.6: Projected Maximum Day Hydraulic Grade Line ........................................................... 45
Tables
Table 2.1: Historical Water Demand ................................................................................................ 4
Table 2.2: Average Seasonal Water Demands ................................................................................. 8
Table 2.3: Water Demand Forecast ................................................................................................. 9
Table 2.4: Storage Capacity Requirements .................................................................................... 11
Table 3.1: Prior Lake Well Information ......................................................................................... 13
Table 3.2: Prior Lake Well Pumping Capacity to WTF .................................................................... 15
Table 3.3: Prior Lake Well Pumping and SMSC Capacity ............................................................... 16
Table 3.4: Water Storage Facilities Summary ................................................................................ 23
Table 3.5: Needed Fire Flows for Residential Homes .................................................................... 24
Table 3.6: Well Water Quality ........................................................................................................ 28
Table 3.7: Iron and Manganese Removal ...................................................................................... 29
Table 6.1: Future Watermain Costs ............................................................................................... 48
Table 6.2: Cost and Implementation Schedule .............................................................................. 49
Appendix
Appendix A: Existing and Future Land Use Maps
Appendix B: Well Hydrographs
Prepared by: Bolton & Menk, Inc. EXECUTIVE SUMMARY
Water System Plan Update ǀ T21.113723 Page 1
I. EXECUTIVE SUMMARY
The purpose of this plan is to evaluate and update the City of Prior Lake’s water system plan. This
plan will evaluate future design considerations with regards to water system planning and
infrastructure, as well as current and future water demands. The existing facilities and
infrastructure are discussed along with the condition of the facilities. Future improvements are
discussed in this report with the intent of updating the water model to reflect how future
improvements will impact average day and maximum day pressures along with maximum day fire
flows in newly developed areas based on the City’s future land use planning.
The design period for this report is 20 years, yielding a design year of 2037. Future projections for
water usage are based on Metropolitan Council population projections and the 2005 through 2016
historical water usage for the City of Prior Lake. Historically, from 2005 to 2016, the City of Prior
Lake saw an increase in population served of 16.5%, from 21,395 in 2005 to 25,616 in 2016.
Population is a driving factor in water demands and the per capita demand for a community.
Historically for Prior Lake, the residential demand and total per capita demands have averaged 70
and 95.3 gallons per capita per day (gpcd) from 2005 through 2016, respectively. Average day
demand has remained relatively consistent over the 10-year historical period. The historical
average of the average day demand is 2.20 MGD.
Maximum day demand has seen a more significant decline since 2005. Two major peaks occurred
in 2007 and 2012, which correspond to years with drought and thus increased water usage for
activities like lawn irrigation. In 2007, the maximum day demand was 7.03 MGD, while in 2012
the maximum day demand reached 6.61 MGD. Overall, the maximum day demand shows a
steadily decreasing demand. The average maximum day demand over the previous 10 years is 5.58
MGD.
Evaluation of the categorical water usage indicates that residential water accounts for 76% of the
total water used. Irrigation accounts for the second largest use category with 10% of the total
water. The City water usage is third at 5% of the total water usage. Commercial water use comes
in fourth at 4% of the total water, followed by unaccounted for water (3%) and lastly institutional
water (2%).
Water demand projections indicate that by the design year of 2037, the average day demand is
expected to be 2.82 Million Gallons per Day (MGD) with a maximum day demand of 6.68 MGD.
The current Water Treatment Facility (WTF) is designed to handle 7.5 MGD, which is sufficient for
Prepared by: Bolton & Menk, Inc. EXECUTIVE SUMMARY
Water System Plan Update ǀ T21.113723 Page 2
current and projected demands. Water storage is another important factor in evaluation of the
infrastructure. Currently, there is adequate storage for current demands and no new facilities are
needed at this time.
Analysis of the storage capacity for future demands indicates that by the design year of 2037, there
will be a surplus in storage capacity of approximately 430,000 gallons. AWWA recommends that
the storage capacity be equal to or greater than the average day demands. With a storage capacity
of 3.25 million gallons (MG), Prior Lake exceeds this recommendation.
Water supply for Prior Lake is from 7 municipal wells and from two interconnections. The City
has two interconnections, one with the Shakopee Mdewakanton Sioux Community (SMSC) and one
from the City of Savage. With these two interconnections, the City is provided with a sufficient
water supply. However, if these two interconnections are not included, the addition of well 10 is
required by 2033 to maintain a firm well capacity (capacity with the largest well out of service)
greater than the maximum day demand.
Historical water model figures, which are found in Section 3 of this report, were used to evaluate
the distribution system to ensure it has adequate pressures and fire flows. The water model
indicates that the City maintains a pressure of greater than 30 – 40 psi throughout the system at
average and maximum day flows. It is recommended by Ten States Standards to maintain at least
35 psi in the system at any one time. The City currently exceeds this recommendation. The City
currently has fire flows that exceed 3,500 gallons per minute (gpm) throughout a majority of the
City. The Insurance Service Office (ISO) has recommendations for fire flows based in residential
areas. Using these recommendations, the City of Prior Lake was determined to have exceeded the
recommended fire flows.
Future improvements are based on the future land use map found in Appendix A. The updated
water model figures include maps showing: future improvements and infrastructure, average day
pressure, maximum day pressure, and maximum day fire flows. The goal for the water model
update was to evaluate how future development will affect the pressures and fire flows throughout
the system and to determine what new infrastructure and watermains are required to maintain 40 –
50 psi at average day flows throughout the future land use areas. The main improvements to the
system include looping new watermains and extending existing watermains to maintain adequate
pressure. Future capital improvements along with preliminary costs are presented at the end of this
report. This report should be continually updated and modified as the City of Prior Lakes’ water
system changes and as water demands change through the design year of 2037.
Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA
Water System Plan Update ǀ T21.113723 Page 3
II. WATER SYSTEM DESIGN CRITERIA
GENERAL
This Section of the Plan develops the performance criteria under which the water system will
be evaluated and/or designed. This involves an evaluation of historical population and future
growth, water use patterns and projections, water storage requirements, required fire flows,
and the distribution system pressure requirements. This section will form the design basis of
the Water Plan. The water model for the City of Prior Lake will be instrumental in
developing future design criteria guidelines related to the distribution system.
DESIGN PERIOD
Typically, water systems and the infrastructure are designed on a 20-year design period, as
there is significant capital improvements required after 20 years to improve hydraulic
capacity, efficiency, or by replacing process components. Therefore, the design period for
this water plan update will go through 2037.
Future projections for water usage are based on Metropolitan Council population projections
and the 2005 through 2016 historical water usage for the City of Prior Lake. The 2005
through 2016 water usage is used as a basis to justify demand projections. It does not mean
that the current trends will be exact in future years, but the trends are accurate enough that
any departure from projected assumptions is considered minor and will not impact the timing
of any recommendations proposed throughout the design period of this report.
This plan should be revisited and updated as necessary to ensure that the system
implementation is keeping pace with development, and forecasted population and water
demands. Generally, every 10 years the recommendations and capital improvements should
be refined based on new data and population projections. Another tool that is useful for water
use planning purposes is the Minnesota Department of Natural Resources (MN DNR) Water
Supply Plan (WSP). The WSP is required every 10 years by each community serving more
than 1,000 people. The WSP must be approved by both the MN DNR and the Metropolitan
Council as required by law. Since the WSP is required every 10 years, it is recommended to
update this Comprehensive plan and the WSP at the same time. The most current Prior Lake
Third Generation Water Supply Plan was submitted on October 4, 2017.
PLANNING AREA
The planning area for this report is identified by the City and includes existing land use and
future land use for Prior Lake through 2040. The existing and future land use maps are found
Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA
Water System Plan Update ǀ T21.113723 Page 4
in Appendix A. The future land use map indicates that there is sufficient land to meet the
anticipated growth needs for the City of Prior Lake through 2037.
POPULATION AND WATER USE
Population projections are based on the Metropolitan Councils population projections through
2040. These projections take into account historical population trends, current land use, and
future land use to predict populations.
1. Historical Population and Water Use
Population is associated with water use more than any other factor. Once a per capita
demand is established, it is possible to predict future populations and future water
demands using that data. The per capita demand is typically determined based on
historical data over the last 10-years omitting extremely high or low demands as they
can skew the data and make future projections unrealistic. Table 2.1 shows the 10-year
historical population and water demands for the City of Prior Lake.
Table 2.1: Historical Water Demand
Year Population (1)
Average
Demand
(MGD)
Max Day
Demand
(MGD)
Residential Per
Capita Usage
(gpcd)
Total Per
Capita Usage
(gpcd)
2005 21,395 1.93 5.66 61.3 90.3
2006 21,542 2.27 5.98 72.7 105.2
2007 22,111 2.44 7.03 80.9 110.5
2008 22,917 2.32 6.42 73.8 101.1
2009 23,335 2.41 5.78 75.0 103.1
2010 22,796 2.11 4.54 68.1 92.6
2011 23,010 2.22 5.00 71.1 96.6
2012 23,385 2.49 6.61 79.8 106.6
2013 24,223 2.25 6.12 69.6 92.7
2014 24,911 2.02 5.10 62.4 81.2
2015 24,732 2.00 4.25 62.3 81.0
2016 25,616 2.12 4.52 62.7 82.7
Average 2.22 5.58 70.0 95.3
(1) Population estimates are from the MN State Demographer
From 2005 to 2016, the City of Prior Lake saw an increase in population served of
16.5%, from 21,395 in 2005 to 25,616 in 2016. The population trend has steadily
increased over the last 10 years. Based on the historical population, it is anticipated
that the projected population will follow similar growth trends.
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Water System Plan Update ǀ T21.113723 Page 5
Residential per capita demand is calculated based on the volume of water used by
residential customers. The majority of water used within the City is for residential use
and is discussed below. The residential per capita demand has averaged 70.0 gallons
per capita per day (gpcd) from 2005 through 2016. Typically, it is desirable to maintain
a residential demand less than 75 gpcd. Prior Lake’s conservation utility billing and
educational efforts will help to keep the residential demand below this threshold.
The total per capita demand averages 95.3 gallons per capita per day (gpcd) from 2005
through 2016. When the data from 2011 through 2016 is evaluated, the average day
demand is 87 gpcd. This decrease in average per capita demand reflects water
conservation measures the City has been implementing for the last several years. The
per capita demand had a peak in 2012 due to a relatively moderate drought that
occurred that year. This peak does not represent the trend in per capita demand and is
considered an outlier in the data set from 2011 through 2016. Future water usage was
based on the 2001 through 2016 average per capita demand. Overall, per capita
demand shows a decreasing trend over the last 10 years as water conservation measures
were implemented and education about water conservation becomes more public and
easier to find. Starting in 2014, the City began purchasing water from SMSC. Based
on the data in Table 2.1, when the City began purchasing water, the total per capita
demand decreased from the previous year’s demands. This could also be attributed to
increased rainfall in the Metropolitan region during those years.
Average day demand has remained relatively consistent over the 10-year historical
period. The historical average of the average day demand is 2.20 MGD. Similar to the
per capita demand, 2012 saw a slight peak in average day demand due to drought
conditions that persisted during the summer months. Overall, there have not been any
major fluctuations in average day demand. However, the demand has slightly
decreased since 2012, which could be represented by increased precipitation and efforts
by the City to implement water conservation techniques and programs.
Maximum day demand has seen a more significant decline since 2005. Two major
peaks occurred in 2007 and 2012, which correspond to years with drought and reduced
precipitation. In 2007, the maximum day demand was 7.03 MGD, while in 2012, the
maximum day demand was 6.61. Overall, the maximum day demand shows a steadily
decreasing demand. The average maximum day demand over the previous 10 years is
5.58 MGD. As the demand continues to decrease, this drives the peaking factor down
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Water System Plan Update ǀ T21.113723 Page 6
since the max day demand becomes closer to the average day demand. The most
significant decrease in max day demand occurred from 2012 to 2016, which is similar
to the average day demand and the total per capita demand over the same timeframe.
Maximum day demands are most likely decreasing due to the implementation of water
conservation measures and education about conserving water being more easily
accessible to customers. Figure 2.1 represents the trends in average and maximum day
demands from 2005 through 2016.
Figure 2.1: Average and Maximum Day Demand Trends
2. Water Use by Category
One way to analyze water consumption and historical demands is to observe who uses
the water. Categorizing water use within a community can provide insight on where to
prioritize water conservation efforts and provides valuable information when making
future water demand projections. The average water consumption by category for
residential, commercial, industrial, and other uses is shows in Figure 2.2.
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
2004 2006 2008 2010 2012 2014 2016Demand (MGD)Average Day Demand Max Day Demand
Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA
Water System Plan Update ǀ T21.113723 Page 7
Figure 2.2: Prior Lake Water Use by Category
As discussed above, residential water usage is the largest category in the City of Prior
Lake. The land use promotes residential development driving the water use up in this
category. There is limited commercial and industrial development in Prior Lake
making these water use categories much smaller than the residential demand. The
residential demand consists of typical household uses including lawn and garden
watering, flushing toilets and taking showers, running washing machines, cooking,
cleaning, and all other household water uses. As shown in Table 2.1, the residential per
capita demand is 70.0 gpcd and according to Figure 2.2, residential water accounts for
76% of the total water. Irrigation accounts for the second largest use category with
10% of the total water. The City water usage is third at 5% of the total water usage.
This category includes water used by the City for hydrant flushing, ice-skating rinks,
vehicle washing, backwashing at the Water Treatment Facility and any other water
used by the City for daily operations. Commercial water use comes in fourth at 4% of
the total water, followed by unaccounted for water (3%) and lastly institutional water
(2%).
3. Seasonal Water Use
Seasonal water use was evaluated for Prior Lake with results found in Table 2.2. The
table shows total volume of water used in the summer months compared to the winter
months. For the purpose of this evaluation, summer months were considered May
through September and winter months were October through April.
Residential
76%
Commercial
4%
Institutional
2%
City Water
5%
Irrigation
10%
Unaccounted For
3%
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Water System Plan Update ǀ T21.113723 Page 8
Table 2.2: Average Seasonal Water Demands
Year Population Summer
Usage (MG)
Winter Usage
(MG)
Summer Per Capita
Demand (gpcd)
Winter Per Capita
Demand (gpcd)
2005 21,395 406 298 52.0 38.2
2006 21,542 515 311 65.6 39.6
2007 22,111 580 312 71.9 38.6
2008 22,917 532 314 63.6 37.5
2009 23,335 561 317 65.9 37.3
2010 22,796 430 341 51.7 41.0
2011 23,010 474 338 56.4 40.2
2012 23,385 579 331 67.8 38.8
2013 24,223 499 320 56.5 36.2
2014 24,911 422 316 46.5 34.7
2015 24,732 409 322 45.3 35.7
2016 25,616 457 316 48.9 33.8
Average 489 320 57.7 36.7
Results indicate that summer demand is on average 33% greater than winter demands.
This is evident by looking at the total water usage between the seasons and by looking
at the summer per capita demand versus the winter per capita demand. One key reason
for larger summer demands is lawn irrigation. Lawn irrigation is commonly a large
water use category during summer months that can drive up the total volume of water
used during that season. Conserving water with respect to lawn irrigation is discussed
in Section 4 of this report.
The purpose of evaluating seasonal demands is to determine if the City has sufficient
infrastructure to handle peak demands. As indicated in Table 2.1, historical maximum
day demands are commonly above 5.5 MGD. Evaluating seasonal demands will
ensure that consideration is given for planning future improvements to handle the
seasonal variations in water demand. The winter usage provides a good baseline water
usage while summer water usage provides key design details that should be considered
with future planning. Based on the above table, the City has sufficient infrastructure to
handle peak summer month flows. However, as the population continues to grow and
housing with lawn irrigation expands, this will drive up the summer demands to a point
where additional infrastructure may need to be discussed.
4. Projected Population and Water Use
Historic water use (average and maximum day demands) and population projections
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Water System Plan Update ǀ T21.113723 Page 9
can be utilized to help make future water projections. It is also important to consider
changing trends in the amount of growth expected in the industrial and commercial
sectors. These consumers can use large volumes of water for process and general
operation of industry. Expansions of this sector can greatly influence future water
demands. Historically, the City of Prior Lake does not have a large industrial or
commercial water demand. Based on 2016 data, the largest commercial or industrial
water user required only 0.4% of the total annual water delivered to the distribution
system. There are no known anticipated large volume water users planning on locating
in Prior Lake. Commercial and industrial use is anticipated to follow historical trends
and grow as population increases. Residential demand will drive future water
projections. The future demand forecast is shown in Table 2.3.
Table 2.3: Water Demand Forecast
Year
Projected
Total
Population (1)
Projected
Population
Served
Projected Total
Per Capita Water
Demand (GPCD)
Projected
Average Daily
Demand (MGD)
Projected
Maximum Daily
Demand (MGD) (2)
2016 25,616 25,616 83 2.12 4.52
2017 25,941 25,941 87 2.25 5.43
2018 26,266 26,266 87 2.28 5.50
2019 26,591 26,591 87 2.31 5.57
2020 26,916 26,916 87 2.34 5.64
2021 27,241 27,241 87 2.37 5.70
2022 27,566 27,566 87 2.39 5.77
2023 27,891 27,891 87 2.42 5.84
2024 28,216 28,216 87 2.45 5.91
2025 28,541 28,541 87 2.48 5.98
2030 30,166 30,166 87 2.62 6.29
2037 (3) 32,441 32,441 87 2.82 6.68
2040 33,416 33,416 87 2.90 6.82
(1) Total Population Projections based on Metropolitan Council population projections
(2) Peaking Factor based on historical data
(3) Design Year
Water demand projections in Table 2.3 were based on historical trends and the increase
in population. Metropolitan Council System Statements were used to for population
projections through 2040. It is assumed that the projected service population will equal
the projected total population as all future residents will be required to connect to the
City’s distribution system.
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The historical total per capita demand from 2011 through 2016 (excluding 2012) of 87
gallons per capita per day (gpcd) was used to make water demand projections through
2040. This excludes 2012, which was a dry year, which led increased water usage and
a much higher per capita demand over the previous two years and following four years.
It can be acceptable to omit years with extreme drought or extreme precipitation as
outliers as they can skew the data and make future projections unrealistic. Based on
historical trends in per capita demand and future population projections, it is likely that
the total per capita demand will remain consistent around 87 gpcd through 2040. The
reason 2011 through 2016 data was used (excluding 2012) was that the City has
implemented water conservation measures over the last several years and the per capita
demand reflects those efforts. It is important to consider these water conservation
measures when making projections as they can help make accurate projections with
regards to the City’s plan of conserving water and reducing per capita demands.
The projected average day demand was calculated by multiplying the projected total
per capita demand of 87 gpcd by the projected service area population. The projected
average day demand shows a slightly increasing demand because the average day
demand is calculated based on population. As the population increases and the per
capita demand remains constant, the average day demand will slightly increase. By the
design year of 2037, a projected average day demand of 2.82 MGD is expected.
The projected maximum day demand was calculated by multiplying the average day
demand by a peaking factor. The peaking factor used to calculate the projected
maximum day demand is the average peaking factor from 2011 through 2016 of 2.41.
This peaking factor was used to project maximum day demands up to 2030. Ten States
Standards has recommendations for peaking factors using an empirical equation that
calculates peaking factors based on a communities population. Based on Ten States
Standards recommendations, as the population increases, the peaking factor will
decrease. Therefore, as Prior Lakes’ population continues to increase, they should
theoretically see a decreasing peaking factor. Using Ten States Standards
recommendations, the peaking factor for 2030 and 2040 are 2.40 and 2.35 respectively.
Reducing the peaking factor also accounts for improved technology and more water
efficient appliances and water conservation programs that may be implemented in the
City. Using these criteria, a projected maximum day demand of 6.68 MG is projected
in the design year of 2037.
Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA
Water System Plan Update ǀ T21.113723 Page 11
5. Future Water Storage Requirements
AWWA recommends that the storage capacity should equal or exceed average day
demands. Considerations for improving storage capacity are based on the existing
infrastructure and the ability to maintain a storage capacity equal to or greater than the
future water use projections found above. Table 2.4 presents the future storage
capacity requirements necessary for Prior Lake.
Table 2.4: Storage Capacity Requirements
Year Service Area
Population
Average
Day (GPD)
Existing Elevated
Storage (gallons)
Existing Ground
Storage (gallons)
Storage
Excess/Deficit
(Gallons)
2016 25,616 2,117,797 1,750,000 1,500,000 1,132,203
2017 25,941 2,253,084 1,750,000 1,500,000 996,916
2018 26,266 2,281,311 1,750,000 1,500,000 968,689
2019 26,591 2,309,539 1,750,000 1,500,000 940,461
2020 26,916 2,337,767 1,750,000 1,500,000 912,233
2021 27,241 2,365,994 1,750,000 1,500,000 884,006
2022 27,566 2,394,222 1,750,000 1,500,000 855,778
2023 27,891 2,422,449 1,750,000 1,500,000 827,551
2024 28,216 2,450,677 1,750,000 1,500,000 799,323
2025 28,541 2,478,905 1,750,000 1,500,000 771,095
2030 30,166 2,620,043 1,750,000 1,500,000 629,957
2037 (1) 32,441 2,817,636 1,750,000 1,500,000 432,364
2040 33,416 2,902,319 1,750,000 1,500,000 347,681
(1) Design Year
Based on the table above, by the design year of 2037, an excess storage capacity of
432,000 gallons is expected. There is adequate storage capacity through the design
year of 2037 and beyond. The existing ground storage is included in the capacity
because a backup generate is located at the site which can run pumps to convey water
into the distribution system during a power failure.
DISTRIBUTION SYSTEM REQUIREMENTS
1. Watermain Sizing Requirements
Ten States Standards recommends the minimum size of watermain for providing fire
protection and serving fire hydrants to be 6-inches in diameter, with larger mains
required if necessary. In addition, velocities in long watermain segments should be
between 2 and 10 feet per second (fps) with average flows less than 5 fps, with 10 fps
Prepared by: Bolton & Menk, Inc. WATER SYSTEM DESIGN CRITERIA
Water System Plan Update ǀ T21.113723 Page 12
being acceptable during emergency withdrawals for short durations.
2. Pressure Requirements
Water pressures are subject to individual preference. What some may view as adequate
pressure may be viewed as too much or too little pressure. Municipalities are
challenged with balancing pressure with demand and capacity of the system along with
conservation of water. Typically, higher pressures equate to higher flow rates, but
increases the volume of water lost through crack and broken pipes.
Ten States Standards recommends the minimum working pressure in the distribution
system should be 35 psi with normal working pressures ranging from 60 – 80 psi. The
Minnesota Department of Health (MDH) along with Ten States Standards requires the
system to maintain a minimum pressure of at least 20 psi at ground level at all points in
the distribution system under all flow conditions. This ensures that there is adequate
water pressure in the event of a long-term power failure or during an emergency. The
City of Prior Lake desires to have at least 40 – 50 psi in the distribution system for
normal operation. Future consideration should be given to new developments to
maintain pressures greater than 40 – 50 psi.
3. Water Distribution Model
The water model for Prior Lake was updated for this report to show the impacts of
future improvements to the system. Future improvements are discussed in Section 5 of
this report. The model was updated based on future zoning within the City of Prior
Lake. The projected water model including an updated anticipated distribution system
map, anticipated average and maximum day pressure maps, and an anticipated
maximum day fire flow map are provided in Section 5. The improvements relate to
improving fire flow where possible and adding new watermain into areas that are slated
for future development. The water model should be used as a tool to evaluate if
additional infrastructure is required in the distribution system.
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 13
III. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
GENERAL
The City of Prior Lake water system consists of seven (7) active wells (includes one well
used for peak demands only), two (2) elevated storage tanks, one (1) booster station, one (1)
pressure service area, four (4) pressure reducing valves, and a system of trunk and lateral
watermains varying in sizes from 6 inches to 24 inches. Existing trunk watermain and major
water system infrastructure are presented in Figure 3.1.
WATER SUPPLY
1. Wells
The City of Prior Lake’s water supply currently consists of seven wells. A summary of
the existing well data and pumping capacities is presented in Table 3.1.
Table 3.1: Prior Lake Well Information
Well No. 3 4 5 6 7 8 9
Year Installed 1973 1975 1988 2001 2003 2006 2007
Inner Casing Dia. (in.) 16 16 24 & 16 30 & 24 12 24 N/A
Total Depth (ft) 364 345 372 410 640 402 N/A
Capacity (gpm) 1200 1100 1000 1200 450 1200 450
Capacity (MGD)(1) 1.44 1.32 1.20 1.44 0.54 1.44 0.54
(1) Assumes wells pump for 20 hours per day
Wells 7 and 9 are the lowest producing wells available, with each having a capacity of
450 gallons per minute (gpm). Wells 3, 6, and 8 are the largest capacity wells, each
capable of producing 1,200 gpm. However, well number 6 is not connected to the
City’s Water Treatment Facility (WTF) and is only used to supplement the water
supply to meet maximum day demands. All of the wells pump water from the Prairie
du-Chein Jordan Aquifer.
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Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\A_113723_ExistingWatermain_11x17.mxd | Date Saved: 3/16/2018 10:40:32 AMWater Modeling
City of Prior Lake
Figure 3.1: Existing Water Distibution System
March 2018
Legend
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"¬!Booster Stations
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
Watermain Pipe Sizes
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4
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16
18
20
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FeetSource: Scott County, City of Prior Lake, MnGeo
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Water System Plan Update ǀ T21.113723 Page 15
One way to evaluate the pumping capacity and the ability of the wells to meet
maximum day demands, it to evaluate the total and firm well capacities. The total well
capacity is the total capacity of all the wells pumping together to supply water. The
firm well capacity is the pumping capacity of all the wells without the largest
producing well in service. Typically, firm well capacity is used to measure whether or
not there is enough supply to meet demands. If the firm well capacity is not greater
than or equal to the maximum day demand, then there is insufficient water supply to
provide enough water to meet demands. Table 3.2 presents the total and firm well
capacities for the Prior Lake wells based on pumping for 20 hours per day or 24 hours
per day. Using 20 hours per day for well pumping is typical, as it allows for pump
maintenance, partial aquifer recharge, and pump cycling based on elevated storage tank
levels. Pumping for 24 hours represents an emergency in which the City is trying to
supplement an extremely large demand by running the wells constantly.
Table 3.2: Prior Lake Well Pumping Capacity to WTF
Item 20-Hour Pumping (1) 24-Hour Pumping (1)
Firm Capacity Total Capacity Firm Capacity Total Capacity
Well Capacity (gpm) 4,200 5,400 4,200 5,400
Well Capacity (MGD) 5.04 6.48 6.05 7.78
(1) Firm and Total Capacities do not include Well No. 6 as this well is available for emergency use only
2. Interconnections
To supplement water supply and to make up for deficits in pumping capacity during
maximum day demands, the City of Prior Lake has agreements with the Shakopee
Mdewakanton Sioux Community (SMSC) and with the City of Savage to purchase
water to supplement the City’s water supply. The agreement with Savage allows the
City to use up to 1 million gallons of water per day. The current agreement between
SMSC and Prior Lake allows Prior Lake to purchase up to 2.2 million gallons of water
per day. As the population of SMSC grows and water use increases, the total volume
of water the City can utilize decreases to 1.5 million gallons. However, the City will
always be able to use up to 1.5 million gallons of water per day in the future from
SMSC per the agreement. Table 3.3 shows the total capacity including the amounts
available from SMSC.
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 16
Table 3.3: Prior Lake Well Pumping and SMSC Capacity
Item 20-Hour Pumping (1) 24-Hour Pumping (1)
Firm Capacity Total Capacity Firm Capacity Total Capacity
Well Capacity (MGD) 5.04 6.48 6.05 7.78
SMSC Capacity (MGD) 1.5 1.5 2.2 2.2
Total Capacity (MGD) 6.54 7.98 8.25 9.98
(1) Firm and Total Capacities do not include Well No. 6 as this well is available for emergency use only
The City began using the interconnection with SMSC in 2014. Since then, they have
purchased 159, 231, and 270 million gallons of water in 2014, 2015, and 2016,
respectively. The interconnections with SMSC and Savage have helped provide a
supplemental water source to meet the City’s maximum day demands.
3. Impacts on Aquifer Pumping Levels
The City of Prior Lake monitors their supply wells with their SCADA system. The
SCADA system collects readings on the well water levels every 15 minutes. The data
that is collected can be used to view trends in the water levels to adjust the well to
optimize pumping or to determine if there is an issue with the supply in the well. The
resulting well hydrographs are presented in Appendix B. It is important to note that the
data is presented as the monthly average well water level.
The hydrographs shows that well water levels are either stable or show an increasing
trend. An increasing trend means that the water levels are rising over the monitoring
period. Based on the hydrographs, wells 3, 5, 6, 7, and 9 show stable trends in water
levels. Even though the well water levels appears to fluctuate significantly through the
monitoring period, as can be seen for Well No. 7, the overall trend remains stable.
Wells 4 and 8 show an increasing trend in water levels over the monitoring period.
One piece of data that can be collected from the hydrographs is the feet of fluctuation
of the water levels. Observing the seasonal variation of water level can help determine
if there are times of the year when a well has limitations or if there is an issue if
pumping capacity becomes limited. Overall, none of the wells for Prior Lake fluctuate
significantly. During the drought in 2012, it can be seen that almost all wells have a
significant drop in water level elevation. 2012 was the summer that put extreme stress
on the water system as peak day demands became very large. Even with the higher
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 17
than normal usage in 2012, the well water levels recovered to previous levels within the
next couple of years. Prior Lake’s wells appear to be stable with no significant
concerns over water levels at each well. Gaps in the data indicate a time when the
SCADA measurement system was not properly calibrated or it was non-functional.
WATER TREATMENT FACILITIES
Prior Lake has a single Water Treatment Facility (WTF) with a design capacity of 7.5 MGD.
The WTF was constructed in 2009 with the intent of removing iron (Fe) and manganese (Mg)
from the raw well water. Water quality data is discussed later in the Section. The facility has
an aerator to oxidize the iron and manganese in the water. Water then flows into a detention
tank to allow the oxidized particles to settle. The detention time is approximately 30 minutes.
After detention, the water enters one of six gravity filters. The filters are dual media filters
comprised of a silica sand under anthracite coal. There is approximately 30 inches of media
in each filter (15 inches of each material). Potassium permanganate is added prior to the
water entering the filters. The purpose of the potassium permanganate is to oxidize any
remaining manganese in the water. The filtered water is collected in a 1.5 million gallon
water reservoir. Water is transferred to the distribution system by the High Service Pumps
(HSP). Chemical additions and their purpose include:
• Chlorine – used for disinfection
• Fluoride – used to help prevent tooth decay
• Polyphosphate – used to prevent corrosion in the distribution pipes
The WTF is operated by a Supervisory Control and Data Acquisition (SCADA) system. A
large diesel generator serves as a backup to run the WTF in the event of a power failure.
The WTF is designed based on a 20-year design period and is capable of handling current
average and max day flows as determine by the analysis in Section 2 for future demands.
With proper maintenance and upkeep and with the data provided in Table 2.2, the WTF has
adequate capacity for many years.
WATER DISTRIBUTION SYSTEM
The water distribution system consists of all the components necessary to convey water from
the wells or storage facilities to customers in the system.
1. Piping Network/Watermain Routing
The City of Prior Lake water distribution piping consists of 6 inch through 20-inch
diameter cast or ductile iron pipe. The larger (16 – 20 inch) pipes run under large trunk
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 18
highways. These pipes convey large volumes of water throughout the City until
smaller lateral pipes (less than 16 inch) convey water in neighborhoods. The majority
of watermain in the City ranges from 6 inch to 10 inch.
The watermains are looped within the City as to not have a dead end pipe, which could
create water quality concerns. The watermains loop around and connect so the water
flows in a path. Parts of the system do have branched systems that are not looped.
Consideration should be given to looping larger diameter watermains with future
expansion. Extending watermain to future developments and providing looping can
help with maintaining adequate system pressure.
Hydrant flushing is an important maintenance activity to clean out dead end
watermains. The City has been proactive in performing hydrant flushes on critical
watermains. The water distribution-piping network has been well maintained and will
continue to serve the customers of Prior Lake.
2. Pressure Service Areas
Prior Lake is served by a single pressure service area from two elevated storage tanks
and one reservoir at the WTF. Four (4) Pressure Reducing Valves (PRV’s) on the
northern edge of town help by regulating pressures in neighborhoods whom could
otherwise have extremely high or low pressures. There are two booster stations in the
City. One serves one area in the northwestern side of town near the Wilds golf course
and the other serves the Summit Preserve area just north of Co. Rd. 42 and east of Co.
Rd. 18.
3. System Pressures
As discussed above, the City of Prior Lake is served by a single pressure service area.
Both elevated towers and the ground reservoir serve the entire City. Figure 3.2
presents the existing average day pressures throughout the distribution system. Based
on the figure, a majority of the City has pressures greater than 50 psi. Around the lake,
(typically areas with the lowest elevation) pressures are in excess of 70 psi. This
covers the downtown area of Prior Lake as well. Areas on the far southern and western
areas of the City have pressures that dip down into the 40 – 50 psi range. Only areas
that are near the city limits have pressures in the 30 – 40 psi range. However,
development is limited in these areas. The area around the Wilds golf course has
pressures ranging from 50 – 70 psi. The system appears to have adequate pressures to
supply water at average day demands throughout the City.
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 19
Figure 3.3 presents the existing system maximum day pressure. This is the pressure
throughout the system during maximum day demands. When compared to Figure 3.2,
the maximum day pressures slightly decrease throughout the City. Areas around the
lake (typically the lowest portions of the City) maintain a similar system pressure
around 70 – 80 psi (within 10 psi of average day pressures). The greatest impacts
during maximum day are on the South side of the City where in some neighborhoods
pressures drop from 70 – 80 psi down to 50 – 60 psi. The downtown area of Prior Lake
still maintains adequate pressures during max day demands with pressures ranging
from 50 – 70 psi. Even though these are impacted the most, the system pressure is still
adequate throughout the City.
Figure 3.5 shows the existing Hydraulic Grade Line (HGL) throughout the City as
indicated by the model. The HGL is consistent between 1,000 – 1,200 feet for a
majority of the City. On the outskirts of town, in areas where development is limited,
the HGL begins to decrease. This is due to less water infrastructure in these areas and
the limited development. The majority of the City maintains a sufficient HGL
according to the water model. Figure 3.6 indicates that the HGL ranges from 950 –
1,200 feet during maximum day demands. Again, on the western and southern edges
of the City where development is limited and there is less infrastructure, the HGL
begins to decrease in elevation. Even still, the majority of the area in City limits
maintains an adequate HGL during maximum day demands.
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City of Prior Lake
Figure 3.2: Existing Average Daily Pressure
March 2018
Legend
!Ø Wells
"¬!Booster Stations
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Average Daily Pressure
20 - 30 psi
30 - 40 psi
40 - 50 psi
50 - 60 psi
60 - 70 psi
70 - 80 psi
80 - 90 psi
90 - 100 psi
100 - 110 psi
110 - 120 psi
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
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City of Prior Lake
Figure 3.3: Existing Maximum Day Pressure
March 2018
Legend
!Ø Wells
"¬!Booster Stations
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Maximum Day Pressure
20 - 30 psi
30 - 40 psi
40 - 50 psi
50 - 60 psi
60 - 70 psi
70 - 80 psi
80 - 90 psi
90 - 100 psi
100 - 110 psi
110 - 120 psi
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
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Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 22
WATER DISTRIBUTION FACILITIES
1. Pressure Reducing Valves
Four (4) Pressure Reducing Valves (PRV’s) are used on the norther edge of the City to
help maintain adequate pressures. The PRV’s are operated and maintained by the City.
These stations help prevent excess pressures in the areas around the Wilds golf course.
The PRV’s are in good condition. In addition, there is a check valve located
downstream of the Summit Preserve neighborhood at the intersection of Kensington
and Co. Rd. 42. The check valve is meant to keep high pressure flow from moving
south of Co. Rd. 42. However, should the Summit Preserve booster station fail or be
taken off line for some reason, water would still be able to flow into the Summit
Preserve neighborhood through the check valve.
2. Booster Stations
Currently, Prior Lake operations one booster station located just west of the
intersection of Wilds Parkway NW with Wood Duck Trail NW. The area around the
Wilds golf course is at a higher elevation than a majority of the City. The existing
water towers do not provide sufficient hydraulic grade to maintain adequate water
pressures in this area. The booster station helps to increase water pressure and flow in
this area. Based on the water model shown in Figures 3.2 and 3.3, the booster station
maintains a pressure of greater than 40 – 50 psi during both average day and maximum
day. The booster station is in good condition to continue to supply water for future
demands.
A new booster station is planned to be installed in 2018 in the Summit Preserve area.
The current model for maximum day pressures (Figure 3.3) indicates that at the north
side of the development, pressures drop to around 30 - 40 psi. This new booster station
will increase pressure and flows to the new Summit Preserve development.
WATER STORAGE FACILITIES
1. Types and Capacity of Storage Facilities
Currently, the City of Prior Lake has three storage facilities totaling 3.25 million
gallons of storage capacity. There are two elevated storage facilities with a capacity of
1.75 million gallons. In 2009, the City constructed a new Water Treatment Facility
(WTF), which contains a large reservoir that has pumps and backup generator. Since
there are pumps and a generator that can pump the water in the event of a power
failure, the 1.5 million gallon reservoir at the WTF is included in the total storage
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Water System Plan Update ǀ T21.113723 Page 23
capacity. A summary of the storage facilities is presented in Table 3.4.
Table 3.4: Water Storage Facilities Summary
Structure Name Location Type of Storage
Structure
Year
Constructed
Primary
Material
Storage Capacity
(Gallons)
South Tower Tower St. SE Elevated storage 1973 Steel 750,000
North Tower Cedarwood St. SE Elevated storage 1986 Steel 1,000,000
WTP Clearwell 16335 Itasca Ave. SE Ground storage 2009 Concrete 1,500,000
Total 3,250,000
AWWA recommends that the storage capacity should equal or exceed the average day
demand. Based on the historical data provided in Table 2.1, the current storage
capacity is adequate for current average day demands. Using Table 2.4, the analysis of
storage capacity, and the future average day projections, by 2025 there is an estimated
average day demand of 2.48 MGD yielding a surplus storage capacity of 770,000
gallons. Looking at 2030, the projected average day demand is 2.62 yielding a surplus
in storage of 630,000 gallons. By the design year of 2037, an excess of 430,000
gallons of storage capacity is expected. There is adequate storage capacity for the City
of Prior Lake through the design year. Both elevated towers are in good condition and
have several more years of useful life remaining.
2. Minimum Use
One way to evaluate the adequacy of storage capacity is to evaluate the minimum use
to see if there is sufficient turnover of water during winter months to prevent freezing
in the storage facilities. A good rule is to allow water to turnover every couple of days
in the winter. Currently, the average day demand averages approximately 2.22 MGD.
Utilizing the full storage capacity of 3.25 MG, the water turnover is about every 1.5
days. Using the future demands, by 2037 the average day demand is anticipated to be
2.82 MGD, yielding a turnover every 1.15 days (if no extra storage facility is
constructed). Based on this simple analysis, there is a good storage supply and water
turnover in the City to prevent water from freezing in the towers during winter months.
3. Existing Fire Demand Requirements
Water modeling can be used to evaluate available fire flows in a City. This can be
beneficial for planning purposes when evaluating distribution system improvements.
The guide for determining required fire flows is developed by the Insurance Service
Office (ISO). When designing future improvements, it is important to account for
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Water System Plan Update ǀ T21.113723 Page 24
needed fire flows. The needed fire flow differs between structures and building types
such as residential, commercial, or industrial. For single-family homes, the following
table should be considered for needed fire flows.
Table 3.5: Needed Fire Flows for Residential Homes
Distance Between Buildings (ft) Fire Flow (gpm)
More than 100 500
31 - 100 750 – 1,000
11 - 30 1,001 - 1500
Less than 11 1,501 – 2,000
Continuous 2,500
Commercial and industrial needed fire flows are determined on an individual basis by
evaluating the occupancy area, communication factor, exposure factor, and if a
sprinkler system is installed. Typically, most systems require only 500 – 1,000 gpm of
needed fire flow if a sprinkler system is installed and up to 500 gpm of additional flow
if a sprinkler system is not installed.
Figure 3.4 presents the City of Prior Lakes’ existing maximum day fire flows. As can
be seen on the map below, a majority of the City has a fire flow greater than 3,500
gpm. Areas with less flow are found on the end runs of watermains and along runs
with smaller diameter watermains. The lowest available fire flow according to the
model in Figure 3.4 is between 1,000 and 1,500 gpm. Small areas around the north end
of Lower Prior Lake have the lowest available fire flow. These areas are on the end of
the smaller diameter watermains. However, these areas still have sufficient fire flows
based on the discussion and table above. Overall, the City of Prior Lake has sufficient
fire flow protection.
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Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
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Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\D_113723_MaxFireflow_11x17.mxd | Date Saved: 3/15/2018 11:13:34 AMWater Modeling
City of Prior Lake
Figure 3.4: Existing Maximum Day Fire Flow
March 2018
Legend
!Ø Wells
"¬!Booster Stations
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Available Fireflow
0 - 500 gpm
500 - 1000 gpm
1000 - 1500 gpm
1500 - 2000 gpm
2000 - 2500 gpm
2500 - 3000 gpm
3000 - 3500 gpm
3500 + gpm
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
!(!(!(!(UT
UT
3P
3P
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!Ø
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!Ø!Ø !Ø
Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
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Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\E_113723_ExistAvgDayHydGradeLine_11x17.mxd | Date Saved: 3/15/2018 1:58:24 PMWater Modeling
City of Prior Lake
Figure 3.5: Existing Average Daily Demand - Hydraulic Grade Line
March 2018
Legend
!Ø Wells
"¬!Booster Stations
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Existing Average DailyDemand - HGL
600-800 ft
800-1,000 ft
1,000-1,200 ft
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
!(!(!(!(UT
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Well No. 9 Well No. 8
Well No. 6
Well No. 5
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Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
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Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\F_113723_ExistMaxDayHydGradeLine_11x17.mxd | Date Saved: 3/16/2018 10:55:53 AMWater Modeling
City of Prior Lake
Figure 3.6: Existing Maximum Daily Demand– Hydraulic Grade Line
March 2018
Legend
!Ø Wells
"¬!Booster Stations
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Existing Maximum DailyDemand - HGL
200 - 450 ft
200 - 450 ft
450 - 700 ft
700 - 950 ft
950 - 1,200 ft
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 28
WATER QUALITY
1. General
The purpose of this section is to evaluate the water quality of the Prior Lake Water
System and detail the treatment methods used. The section will also detail the current
drinking water standards and how the Prior Lake water quality compares to these
standards.
2. Water Quality and Treatment
The Prior Lake water quality is considered good. The water is considered potable since
it does not exceed any limits set forth in the National Primary Drinking Water
Standards. However, due to iron and manganese levels present in the aquifer, the water
exceeds levels above the National Secondary Drinking Water Standards. The
Secondary Drinking Water Standards has limits of 0.3 mg/L for iron (Fe) and 0.05
mg/L for manganese (Mn). Excessive iron and manganese can cause red and black
stains when the water is used for irrigation and other household uses. It can also create
taste and odor problems and cause plumbing issues over time. Well No. 6 and 7 are the
only two wells that have iron levels that exceed the Secondary Standard of 0.3 mg/L.
All of the wells exceed the Secondary Standard of 0.05 mg/L for manganese. Table 3.6
identifies the well manganese levels and the respective concentrations and loads based
on the well pumping capacity. Well water is typically blended from certain wells to
achieve a lower overall manganese concertation entering the WTF. As seen in Table
3.6, each well (except well 7) accounts for approximately 23% of the total manganese
load pumped from each well.
The City’s current water treatment facility (WTF) uses an aerator, chemical addition,
and gravity filtration to oxidize the iron and manganese in the water and remove it from
solution. Details of the treatment facility are discussed in Section 3 of this report. The
Table 3.6: Well Water Quality
Well No.(1) Well Flow
(gpm)
Well Flow (2)
(MGD)
Manganese
Concentration (mg/L)
Manganese Load
(lbs./day)
Percent of Total
Manganese
Load
3 1,200 1.44 0.28 3.36 23.1%
4 1,100 1.32 0.319 3.51 24.1%
5 1,000 1.2 0.343 3.43 23.6%
7 450 0.54 0.199 0.90 6.2%
8 1,200 1.44 0.278 3.34 23.0%
(1) Well No. 9 data was omitted as data was not available at the time this report was written
Assumes pumping at 20 hours per day
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 29
WTF is very effective at removing iron and manganese levels to below the National
Secondary Drinking Water Standards. Table 3.7 represents the average iron and
manganese concentrations and loads that enter the WTF and the average effluent
concentrations and loads leaving the WTF.
Table 3.7: Iron and Manganese Removal
Raw/Treated Constituent Average Concentration
(mg/L)
Mass Load
(lbs./day)
Raw Iron 0.22 3.92
Treated Iron 0.01 0.27
Raw Manganese 0.53 9.62
Treated Manganese 0.03 0.63
On average, 9.62 lbs/day of manganese enters the WTF in the raw water supply. The
manganese load in the effluent is 0.63 lbs/day, approximately two times the load of
iron leaving the filters. The mass loadings were calculated based on the average daily
flow from the last six years (2010 – 2016) of 2.17 MGD. Effluent iron concentrations
average 0.01 mg/L and effluent manganese concentrations average 0.03 mg/L. Overall,
the filter achieves a 93% removal of iron and 93% removal of manganese producing an
effluent water quality higher than the standards set in the Secondary Drinking Water
Standards.
a) Fluoridation
Fluoride is added to the treated water before it is sent into the distribution system.
Fluoride is added to aide in cavity protection for customers and prevents tooth
decay.
b) Chlorination
The City disinfects the supply water using chlorine as a primary disinfectant.
The City uses free chlorine as the source of chlorine. This is achieved by
breakpoint chlorination where chlorine is added at a specific dose which oxidizes
all of the natural or added ammonia in the water until all that is left is the free
chlorine molecules. This type of disinfection provides a stable and powerful
disinfectant that inactivates organisms in the water and provides a suitable
residual in the distribution system.
3. Current Drinking Water Standards
The City follows all of the enforcement standards set forth in the Environmental
Protection Agency’s National Primary Drinking Water Standards. These standards are
Prepared by: Bolton & Menk, Inc. EXISTING WATER SYSTEM FACILITIES AND INFRASTRUCTURE
Water System Plan Update ǀ T21.113723 Page 30
enforceable limits that each public water supply system must adhere to and provide
annual updates to the public. Prior Lake accomplishes this in the annual drinking water
report.
4. Proposed Drinking Water Standards
With the current WTF treating for iron and manganese and removals below the
National Secondary Drinking Water Standards, the City is sending treated water into
the distribution system that is safe and sustainable for customer use in the City. The
City will continue to monitor water quality per Federal and State regulations.
Prepared by: Bolton & Menk, Inc. WATER CONSERVATION
Water System Plan Update ǀ T21.113723 Page 31
IV. WATER CONSERVATION
GENERAL
The purpose of this section is to discuss how water conservation plays a key role in future
water planning and how these concepts can be implemented by the City. Water conservation
is becoming an important issue where water is viewed as an important resource. Conserving
water may help with demand reduction and relaxes stress on the distribution system and wells
during high usage months. Water conservation can include a vast range of techniques and
strategies from the addition of rain barrels to capture rainfall for lawn irrigation, to drip
irrigation systems for larger gardens, to even replacing regular household appliances with
energy and water efficient appliances. This section will discuss concepts for reducing water
use, and peak day demands along with the current water rates and the water lost throughout
the system and how they relate to water conservation.
REDUCING USE
Reducing water use is one of the largest factors for decreasing the per capita demand and
water lost through the system. Most of the water in a community goes towards residential
use. As discussed earlier in this report, residential water use includes water used in all
household appliances, cooking, cleaning, toilets, showers, and lawn irrigation. Seasonal
usage can affect what water is used for with respect to residential demand. Typically,
commercial and industrial demands remain relatively constant throughout the year, as the
day-to-day operations of the facility do not change significantly. Reducing water use in these
facilities involves discussion with the owner and what techniques may work for each industry
or business.
During winter months, a baseline demand can be established because almost all of the
residential water is used for normal household uses with the exception of lawn irrigation.
This baseline demand can give an estimate to how much water is required for residential
customers on a regular basis with no lawn irrigation. However, during summer months when
lawn irrigation is at a peak, this seasonal demand can play a large role in how much water is
required for customers. The analysis of seasonal demands is discussed in Section 2 of this
report. The analysis concludes that the summer demand is on average, 33% greater than
winter demands.
Seasonal peak water demands are often the result of lawn irrigation. Keeping up with peak
demands requires the construction of additional water supply and storage facilities sooner
Prepared by: Bolton & Menk, Inc. WATER CONSERVATION
Water System Plan Update ǀ T21.113723 Page 32
than they may be otherwise warranted. If a City is treating this water that may mean
expansion or addition of the Water Treatment Facility (WTF), just to keep up with these
demands. With an average of 76% of water going to residential use, lawn irrigation can play
a major role in the seasonal demand for this customer category. Currently, the City has
sufficient water supply with the interconnections to keep with the maximum day demands
and seasonal water use. However, if future water use continues to grow without any sort of
water conservation measure to limit irrigation, Prior Lake may be required to add Well 10
sooner than anticipated.
Reduction of lawn irrigation to help control demands is typically accomplished through odd-
even day or even time-of-day watering restrictions. Prior Lake currently has an ordinance for
odd-even day watering that has helped reduce peak day and seasonal demands. The City has
also been proactive in implementing a tiered rate structure that bills more for higher water
usage. This has helped reduce water usage over the past few years as is evident in Table 2.1
(Historical Demands).
The City currently bills water customers on a bi-monthly basis. The City should consider
monthly billing as a method to help with conservation as customers will see and track their
usage more frequently and have a chance to make changes on usage more quickly. This
would require additional time by the City to put together customer bills and possibly
reconfiguration of the City’s billing system/software.
The water rate system is a two-tier system for usage rates. The City should consider adding a
third, higher rate on high usage. Many other communities have a three-tier system with the
higher tier targeting those high usage customers.
Reducing water lost in the system is accomplished through leak detection and annual water
audits. The City currently performs a leak detection on a third of the City each year. This
means that every three years the entire City will have updated leak detection results. It is
important to use the leak detection information yearly for Capital Improvement Planning to
target areas where the volume of water lost in the system is greatest. Water losses can also be
targeted by installing new enhanced meters and repairing and recalibrating current meters.
Water conservation is a key factor in reducing water use. Conservation measures typically
involve education along with an incentive and regulation to encourage water conservation.
While some of these measures such as: billing inserts on water conservation or rebates for
installing a water efficient appliance or grant programs for adding rain barrels, can help with
Prepared by: Bolton & Menk, Inc. WATER CONSERVATION
Water System Plan Update ǀ T21.113723 Page 33
reducing water use, they will not completely eliminate the need for additional wells or water
storage. However, they could delay the implementation of the infrastructure or reduce the
total future required capacity.
REDUCING PEAK DEMANDS
Historically, the maximum day demands for Prior Lake frequently exceed 5 MGD as
indicated in Table 2.1. These peak day demands typically occur in the summer months when
lawn irrigation is at its highest. The water used for lawn irrigation is typically what drives
maximum day demands. The volume of water devoted to lawn irrigation can be moderated
by the odd-even day watering restriction. There has been moderate success in Prior Lake
since this restriction has been implemented. This restriction may help reduce seasonal
demands due to lawn irrigation, but it does not significantly reduce overall use. Reducing
overall use involves more complex water conservation techniques as discussed above.
Reducing the peak demands may help reduce stress on the water supply and distribution
system.
Evaluation of historical demands indicates that over the past few years, peak demands have
been decreasing or slightly lower than the previous 10-year average. One contributing factor
could be that Prior Lake has been dedicated to improving the efficiency of the distribution
system and increasing efforts related to water conservation. One of the key elements that has
helped reduce peak demands is the implementation of the tiered rate system that bills more
for higher water use. By continuing to manage the rate system and make changes as
necessary, this may help by controlling the peak day demands experienced during summer
months when water usage is greatest.
WATER RATES
As stated above, the City of Prior Lake has a tiered rate system for residential customers that
bills out bimonthly with the volume reported in thousands of gallons of water used. This type
of billing is considered conservation billing and has helped the City reduce overall water
usage since its implementation. By having water bills reported in gallons, it allows customers
to easily see how much water they use in a given billing period so they can manage their own
water usage and how much they are willing to pay for water. The City currently has a two-
tiered system that bills rates as follows:
• $4.53 per 1,000 gallons for the first 25,000 gallons
• $6.25 per 1,000 gallons for water usage over 25,000 gallons
Prepared by: Bolton & Menk, Inc. WATER CONSERVATION
Water System Plan Update ǀ T21.113723 Page 34
The City evaluates water rates on a yearly basis and updates them as necessary. The latest
rate adjustment was made in January of 2017.
WATER LOSS
The City of Prior Lake has submitted their Third Generation Water Supply Plan (WSP) to the
Minnesota Department of Natural Resources (DNR). In the preliminary WSP, unaccounted
for water is estimated at approximately 6.9% (2005 – 2016 average). When evaluating the 6-
year average (2011 – 2016), the unaccounted for water averages 2.8%. The reason the 2005 –
2016 unaccounted for water is higher is because from 2005 – 2007 Prior Lake had
unaccounted for water greater than 10% each year. Since then, the unaccounted for water has
significantly decreased and has remained less than 7% per year. The DNR has a threshold of
keeping unaccounted for water less than 10%. Based on the available data, Prior Lake is well
below the 10% threshold. However, over the last 11 years the 6.9% average unaccounted for
water equates to approximately 55 million gallons of water lost.
Lost water can attributed to leaks from the system, unmetered use (i.e. firefighting, street
sweeping, ice rink flooding, hydrant flushing, construction etc.), or even unauthorized use.
Water losses means lost revenue to the utility of the water is not metered or if it lost due to
leaks in the system.
With the addition of enhanced water meters on commercial buildings and automated meters
in residential homes, this has helped reduce the amount of water that goes unmetered in the
system over the last several years. Maintaining a meter change-out schedule and/or a
maintenance schedule can help reduce the errors due to water meters.
As stated earlier in this report, the City conducts a leak survey on a third of the City every
year. This helps find and stop leaks that are occurring the City to reduce the amount of water
lost. The leak detection is an important part in system maintenance that should continue
yearly to stop leaks and prevent large volumes of water from leaking and not being metered.
Identifying and correcting leaks early enables utilities to minimize costly repairs of large
watermain failures, and to avoid premature expansion to supply and treatment and storage
facilities.
Another important tool that can be used to help track water losses is a water audit. This can
be as simple as tracking the total volume of water pumped in a year and comparing it to the
volume of water billed to customers. These two numbers should be relatively close to each
other. If they are significantly different, that could indicate that water is being lost in the
Prepared by: Bolton & Menk, Inc. WATER CONSERVATION
Water System Plan Update ǀ T21.113723 Page 35
system somewhere, which results in lost revenue. Overall, Prior Lake has a lower percentage
of unaccounted for water and they have implemented and maintained a quality leak detection
program. These efforts should help track water losses to keep them at a minimum.
Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS
Water System Plan Update ǀ T21.113723 Page 36
V. RECOMMENDED FUTURE IMPROVEMENTS
GENERAL
This section details recommended future improvements to Prior Lakes’ water system to
improve the water supply, treatment, distribution system, and storage facilities. The
recommended improvements are based on evaluation of the existing facilities discussed in
Section 3 and the projected water demands evaluated in Section 2. This Section includes the
updated water system model to show how the infrastructure improvements discussed below
affect average and maximum day pressures, as well as maximum day fire flows.
WATER SUPPLY
Analysis of the water supply indicates that Prior Lake does not require additional wells at this
time. However, it is desirable to maintain a firm well capacity (capacity with the largest well
out of service) greater than the project maximum day demand. Currently, with operating the
wells at 24 hours per day, the City has a firm well capacity of 4,200 gpm, or 6.05 MGD.
Future demands indicate that sometime around 2030, maximum day demands will become
greater than the firm well capacity. However, the City has the agreement with SMSC to
purchase a maximum of 2.2 MGD and a minimum of 1.5 MGD and this capacity allows the
City to push well 10 to 2037. The agreement with SMSC is a key component of the City’s
water system and affords the City the capacity needed so no major water improvements are
needed. It is noted to look at adding well 10 in 2037. It is best to evaluate the long-term
water supply plan for Prior Lake to discuss if there is a desire to add well 10 or maintain the
interconnections with SMSC and Savage.
WATER TREATMENT FACILITIES
The current WTF has adequate capacity for current and future demands. The facility
adequately removes iron and manganese from the water to below National Secondary
Drinking Water Standards. No future improvements are necessary at the WTF. Proper
maintenance is an important element in the operation of the WTF. Equipment and coating
systems should be inspected every 20 years and replaced or repaired as needed.
To ensure proper operation of the WTF filters, a filter evaluation should be done every 5 – 7
years. This will help operators understand the “health” of their filters and to help eliminate
potential future problems with the media. The filter evaluation will also help determine if the
media should be replaced and approximately, when it should be replaced.
Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS
Water System Plan Update ǀ T21.113723 Page 37
WATER DISTRIBUTION SYSTEM
The following are recommended improvements to the distribution system. Improvements
were based on the existing water model figures provided in Section 3 of this report and the
existing and future land use maps in Appendix A. The goal was to try improve the ISO
classification with respect to maximum day fire flows and pressures throughout the system to
meet demands for future development.
It was assumed that areas with residential usage would be similar to historical demands with
regards for required flows and that industrial demands would be similar to historic demands.
These assumptions were used only to update the water model to evaluate required watermain
looping and infrastructure required for the future land use depicted in Appendix A. The
actual development or infrastructure should be an integral part of the City’s planning and the
water distribution system should be developed around the actually planning documents.
1. Watermain
The City of Prior Lakes’ distribution system currently consists of watermains ranging
in size form 6 inches up to 20 inches. As the system continues to grow (as depicted by
the maps in Appendix A and this Section), the need for additional watermain increases.
The new watermains should be added to the system to strengthen the existing loops or
to create new loops in areas not currently served by the distribution system. Looping
watermains in the most effective method for increasing average and maximum day
pressures as well as increasing the fire flow in an area. Figure 5.1 depicts the
anticipated future improvements to the distribution system with regards to locations for
placement of new watermains. The intent is to show general locations and preferred
looping routes. The actual implementation and placement of the watermains should be
integrated in consideration with other utility installations and actual planned
developments and roads.
The main areas of focus for the addition of watermain were on the west and north
sections of the City. These areas will see substantial future development according to
the future land use map. To best serve these areas, future watermain additions were
developed based on the watermain currently installed with sizing and looping additions
used to maintain adequate pressure and fire flows.
Based on Figure 5.1, the proposed watermain additions on the west side of the City
Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS
Water System Plan Update ǀ T21.113723 Page 38
include extending the 16-inch watermain that currently terminates north of highway 13,
along highway 13 to the southwest. This new 16-inch watermain would serve the areas
that the future land use map in Appendix A depicts as primarily industrial and urban
low-density residential land use. Looping this new 16-inch watermain through these
sections will provide adequate flows and pressures to these areas. In addition,
extending the 20” watermain that is currently installed up to the intersection of
Marschall Rd. at Belmont Ave. NW, to the west and south along Marschall Rd., will
provide adequate flows and the ability to loop watermain through these areas.
Additionally, more loops can be created depending on how the development in these
areas progresses. Some ideas for additional loops include adding 8-inch loops through
residential neighborhoods and extending 10-inch or 12-inch watermains through
industrial developments. The new 16-inch watermain would be connected to the
existing watermain that runs around the north end of Upper Prior Lake.
On the north side of the City, the projected land use is a mix of urban low-density to
urban high-density housing with additional industrial land throughout. To best serve
this area, the existing 16-inch watermain that runs along County Road 42 can be
extended into the northwest corner of the City. This loop would serve the projected
residential demand. Additionally, to help maintain adequate flows and pressure, the
16-inch watermain from the SMSC WTP, would be extended North along County Road
82 and ultimately connect to the 16-inch watermain on County Road 42.
To meet demands in the north-central section of the City, the existing 12-inch
watermain running along County Road 21 would be extended east and west to serve the
projected residential and industrial areas. A new 12-inch watermain would also be
extended north along Pike Lake Trail NE to the City limits. This 12-inch line would
also have an 8-inch line running to the east. Several pressure-reducing valves are
required in this scenario to help even out the pressures. The additional loops created
pockets of low or high pressures that are regulated by using the PRV’s.
Average day pressures throughout the City are depicted in Figure 5.2. With the
addition of the new watermain loops to serve the future development areas, the City
can expect to maintain an average day pressure ranging from 70 – 90 psi in the western
section of the City. The pressures here would be adequate for future residential and
industrial development as depicted in the future land use map in Appendix A.
Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS
Water System Plan Update ǀ T21.113723 Page 39
In the north section of the City, average daily pressures in the new land use areas range
from 70 – 90 psi with some areas having pressures in the 50 – 60 psi range. As noted
above, this area has several PRV’s added. The PRV’s were added to isolate the
Summit Preserve development and allow the new booster station to increase the
pressure, and to control pressures in the areas between County Roads 18 and 21. These
PRV’s help to maintain the pressures above 70 psi for a majority of the area. Figure
5.5 indicates that the Hydraulic Grade Line (HGL) throughout the City will remain
constant between 800 – 1,200 feet with the watermain additions shown in Figure 5.1.
This is adequate for future average day demands.
Maximum day pressures using the updated water model are found in Figure 5.3. In the
western section of the City, maximum day pressures ranging from 60 – 80 psi can be
expected. A majority of this area depicted in Figure 5.3 will have a pressure of
approximately 70 psi. In the northern section of the City, maximum day pressures drop
to around 50 psi west of County Road 21, but the majority of the area still maintains
pressures greater than 50 psi. Based on Figures 5.2 and 5.3, with the addition of new
watermain loops, the City can expect to maintain average day and maximum day
pressures greater than 50 psi in all areas. Figure 5.6 indicates that the HGL throughout
the City will be constant in a majority of the City between 1,160 – 1,220 feet. Areas on
the North side of the City can expect to have a HGL between 1,100 – 1,160 feet. The
change in HGL is due to the elevation change in the topography. Overall, the HGL is
adequate for future maximum day demands.
2. Fire Flow
Based on the current model, a majority of Prior Lake has a fire flow greater than 3,500
gpm, with the lowest modeled fire flow of 500 gpm in small areas around Lower Prior
Lake. The lowest fire flows are in areas with dead end watermains. However, these
areas are directly adjacent to, or are surrounded by areas with fire flows greater than
3,500 gpm. Overall, the City already has fire flows that exceed recommendations
found in Table 3.4 above. The addition of new watermain will still help increase the
available fire flow in areas around the City limits and in all future development areas.
The additional watermains increased the projected maximum day fire flows to greater
than 3,500 gpm in all future land use areas. This indicates that the looping and sizing
of watermains was adequate to provide sufficient fire flow to meet the criteria set up in
Table 3.4.
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3P
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!Ø
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Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
?±A@
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Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\G_113723_20Yr_Watermain_11x17.mxd | Date Saved: 3/15/2018 1:39:09 PMFigure 5.1: Anticipated Water Distribution System
March 2018
Legend
!(Proposed Valves
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
!Ø Wells
"¬!Booster Station
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Future Watermain Pipes
8
10
12
16
20
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
Water Modeling
City of Prior Lake
!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT
UT
3P
3P
"¬!
!Ø
!Ø
!Ø!Ø
!Ø!Ø !Ø
Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
?±A@
?±A@
GÜWX
GÜWX
G±WX G±WX
GuWX GrWX
G¸WX
GuWX
GwWX
GqWX
GkWX
Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\H_113723_20yr_AverageDailyPressure_11x17.mxd | Date Saved: 3/16/2018 3:31:08 PMFigure 5.2: Projected Average Daily Pressure
March 2018
Legend
!(Proposed Valves
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
!Ø Wells
"¬!Booster Station
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Future Watermain Pipes
8
10
12
16
20
Average Daily Pressure
20 - 30 psi
30 - 40 psi
40 - 50 psi
50 - 60 psi
60 - 70 psi
70 - 80 psi
80 - 90 psi
90 - 100 psi
100 - 110 psi
110 - 120 psi
City Limits03,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
Water Modeling
City of Prior Lake
!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT
UT
3P
3P
"¬!
!Ø
!Ø
!Ø!Ø
!Ø!Ø !Ø
Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
?±A@
?±A@
GÜWX
GÜWX
G±WX G±WX
GuWX GrWX
G¸WX
GuWX
GwWX
GqWX
GkWX
Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\I_113723_20YrMaxDayPressure_11x17.mxd | Date Saved: 3/15/2018 1:36:09 PMFigure 5.3: Projected Maximum Day Pressure
March 2018
Legend
!(Proposed Valves
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
!Ø Wells
"¬!Booster Station
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Future Watermain Pipes
8
10
12
16
20
Maximum Day Pressure
20 - 30 psi
30 - 40 psi
40 - 50 psi
50 - 60 psi
60 - 70 psi
70 - 80 psi
80 - 90 psi
90 - 100 psi
100 - 110 psi
110 - 120 psi
City Limits03,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
Water Modeling
City of Prior Lake
!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT
UT
3P
3P
"¬!
!Ø
!Ø
!Ø!Ø
!Ø!Ø !Ø
Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
?±A@
?±A@
GÜWX
GÜWX
G±WX G±WX
GuWX GrWX
G¸WX
GuWX
GwWX
GqWX
GkWX
Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\J_113723_20yrMaxFireflow_11x17.mxd | Date Saved: 3/15/2018 1:25:56 PMFigure 5.4: Projected Maximum Day Fire Flow
March 2018
Legend
!(Proposed Valves
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
!Ø Wells
"¬!Booster Station
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Future Watermain Pipes
8
10
12
16
20
Available Fire Flow
0 - 500 gpm
500 - 1000 gpm
1000 - 1500 gpm
1500 - 2000 gpm
2000 - 2500 gpm
2500 - 3000 gpm
3000 - 3500 gpm
3500 + gpm
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
Water Modeling
City of Prior Lake
!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT
UT
3P
3P
"¬!
!Ø
!Ø
!Ø!Ø
!Ø!Ø !Ø
Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
?±A@
?±A@
GÜWX
GÜWX
G±WX G±WX
GuWX GrWX
G¸WX
GuWX
GwWX
GqWX
GkWX
Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\K_113723_20yrAvgDayHydGradeLine_11x17.mxd | Date Saved: 3/16/2018 4:14:16 PMFigure 5.5: Projected Average Daily Demand – Hydraulic Grade Line
March 2018
Legend
!(Proposed Valves
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
!Ø Wells
"¬!Booster Station
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Future Watermain Pipes
8
10
12
16
20
Future Average DailyDemand - HGL
0 - 400 ft
400 - 800 ft
800 - 1,200
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
Water Modeling
City of Prior Lake
!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(UT
UT
3P
3P
"¬!
!Ø
!Ø
!Ø!Ø
!Ø!Ø !Ø
Well No. 9 Well No. 8
Well No. 6
Well No. 5
Booster Station
Tank No. 1
Tank No. 2
SMSC WTP
WTP No. 1Well No. 7
Well No. 3 Well No. 4
Booster Station
?±A@
?±A@
GÜWX
GÜWX
G±WX G±WX
GuWX GrWX
G¸WX
GuWX
GwWX
GqWX
GkWX
Spring Lake
PikeLake
Rice Lake
CampbellLake
Geis Lake
HowardLake
Keup'sLake
BuckLake
O'Dowd Lake
UpperPriorLake
Lower PriorLake
TholeLake
Cleary Lake
Map Document: \\arcserver1\GIS\PLAK\T21113723\ESRI\Maps\2017\10.4\L_113723_20yrMaxDayHydGradeLine_11x17.mxd | Date Saved: 3/16/2018 11:19:15 AMFigure 5.6: Projected Maximum Daily Demand– Hydraulic Grade Line
March 2018
Legend
!(Proposed Valves
!(Pressure Reducing Valves
UT Elevated Storage Tanks
3P Water Plant
!Ø Wells
"¬!Booster Station
Watermain Pipe Sizes
3
4
6
8
10
12
16
18
20
Future Watermain Pipes
8
10
12
16
20
Future Maximum DailyDemand - HGL
980 - 1,040 ft
1,040 - 1,100 ft
1,100 - 1,160 ft
1,160 - 1,220 ft
1,220 - 1,280 ft
City Limits
0 3,200
FeetSource: Scott County, City of Prior Lake, MnGeo
!I
Water Modeling
City of Prior Lake
Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS
Water System Plan Update ǀ T21.113723 Page 46
WATER DISTRIBUTION FACILITIES
1. Pressure Reducing Valves
The existing pressure reducing valves (PRV’s) are in adequate condition for several
more years. With proper maintenance and upkeep, they should continue to function as
intended. The check valve at Kensington and Co. Rd. 42 is new and with proper
maintenance will serve the City for a long time. Additional PRV’s may be necessary
as shown in Figure 5.1 to control the pressure gradients on the north side of the City.
The reason the PRV’s were added here was to isolate the Summit Preserve
development to allow the booster station to increase the pressure. It is important to
note that not all of the PRV’s may be needed depending on how future development
progresses. Additional loops may be added to negate the need for some of the PRV’s.
2. Booster Stations
The existing booster station near the Wilds golf course is in adequate condition for
current and future demands. It is recommended to continue with proper maintenance
on the station and infrastructure associated with it.
One improvement that is currently in the construction phase is the addition of the
Summit Preserve booster station. This booster station will be located in the Summit
Preserve area and will be operational in 2018. Currently, there are several homes being
constructed in this new development. There is a large elevation change in this area as
well that will require additional hydraulic lift to maintain water pressures at the highest
elevation.
WATER STORAGE FACILITIES
1. Storage Requirements
AWWA recommends storage capacity equal to or greater than average day demand.
Based on the analysis in Section 2 of this report, the City of Prior Lake will have
approximately 432,000 gallons of excess storage capacity by the design year of 2037
per this report. There is currently enough storage capacity to meet future average day
demands. No future improvements are required for storage facilities. The
recommendation is to continue with proper maintenance and to evaluate the towers as
needed to determine the adequacy of the coating system to ensure that it has several
more years of useful life.
The analysis in Section 3 of this report indicates that the fire storage capacity is
Prepared by: Bolton & Menk, Inc. RECOMMENDED FUTURE IMPROVEMENTS
Water System Plan Update ǀ T21.113723 Page 47
adequate for current and future flows. However, the needed fire reserve plays a critical
role in the needed storage capacity for a water system. Any type of progress that can
be made, such as an ordinance requiring fire suppression systems in all new buildings,
are important considerations that will help reduce the total volume of water required for
fire flows and fire storage.
Prepared by: Bolton & Menk, Inc. ECONOMIC ANALYSIS
Water System Plan Update ǀ T21.113723 Page 48
VI. ECONOMIC ANALYSIS
GENERAL
This section presents the general cost estimates and Capital Improvement Planning (CIP)
schedule anticipated per the discussion of this report. For watermain, the City’s policy is the
developer is responsible for installing 8-inch piping and the City pays for the upsizing
anything larger than 8-inch. Per our future watermain figure the lineal feet of piping and pipe
sizing is determined and table 6.1 shows the amount of future watermain and the City and
developer portion of the future watermain costs.
Table 6.1: Future Watermain Costs
Water
Main Size
(inches)
Length of
Proposed
Water Main
(feet)
Unit Price
($ per
foot) City Cost
Developer
Cost Total Cost
8 28,905 $50 $0 $1,445,250 $1,445,250
10 85 $60 $850 $4,250 $5,100
12 10,230 $80 $306,900 $511,500 $818,400
16 27,940 $95 $1,257,300 $1,397,000 $2,654,300
20 6,970 $120 $487,900 $348,500 $836,400
Subtotals $2,052,950 $3,706,500 $5,759,450
The cost estimates provided in this section are preliminary cost estimates. Table 6.2 in
section B presents the CIP.
Prepared by: Bolton & Menk, Inc. ECONOMIC ANALYSIS Water System Plan Update ǀ T21.113723 Page 49 CAPITAL IMPROVEMENT PLAN AND COST ESTIMATES Table 6.2: Cost and Implementation Schedule Item Year 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 Well 10 $800,000 Water Tower- Cleaning/ Misc. Repairs (2) $10,000 $20,000 $20,000 Water Distribution System Improvements(1) $105,000 $1,110,000 $110,000 $115,000 $100,000 $100,000 $100,000 $100,000 $100,000 $100,000 $100,000 $100,000 750 Kgal Water Tower – Coating Reconditioning $800,000 1.0 MG Water Tower – Coating Reconditioning $1,250,000 Booster Station- Summit Preserve $650,000 Water Treatment Facility: 20-year Renovations $800,000 Water Treatment Facility Filter Evaluation $15,000 $15,000 $15,000 $15,000 DNR Water Supply Plan $30,000 $30,000 Annual Total $755,000 $1,110,000 $110,000 $115,000 $15,000 $110,000 $0 $900,000 $0 $145,000 $20,000 $900,000 $1,250,000 $100,000 $15,000 $920,000 $0 $100,000 $0 $145,000 (1) 2018 – 2021 costs are from the 2017 – 2021 CIP for Prior Lake (2) Water Tower Cleaning includes the cost for cleaning both the 750 Kgal and the 1.0 MG towers together
Prepared by: Bolton & Menk, Inc. ECONOMIC ANALYSIS
Water System Plan Update ǀ T21.113723 Page 50
FUNDING
Several sources are available for funding the above projects. The City of Prior Lake can also
choose to fund the projects by bonding themselves or using cash reserves. It may be more
beneficial to receive state funding for larger projects such as WTF renovations or water tower
renovations as these can cost significantly more than a watermain replacement project. For
these projects, the state of Minnesota has the Public Facilities Authority that funds projects
through the Drinking Water Revolving Fund. This requires placement on the Project Priority
List to receive funding for drinking water projects. The City can also choose to try and
receive different grants to fund the above projects if they are eligible.
Prepared by: Bolton & Menk, Inc.
Water System Plan Update ǀ T21.113723
Appendix A: Existing and Future Land Use Maps
Map Document: \\METROSOUTH1\gis\PLAK\T42112823\ESRI\Pro\112823_StoryMap\112823_CompPlan_Boards_2.0.aprx\112823_Existing_Land_Use_11x17L Date Saved: 9/5/2017 3:26 PM2040 Comprehensive Plan
City of Prior Lake, MN September 2017
Existing Land Use
RevereWay160th Street Southeast
Highwa y 13South170thStreetSouthwes
t
ConnellyParkway
Highw
a
y
1
3
S
o
u
t
h
EagleCreekAvenueSouthe
a
stMarschall Road SouthMarschall Road SouthEagleCreekAvenueNortheastT u rnerD riveSo ut hwest BooneAvenueSouthMysticLakeDriveNorthwestHighway 13 South158thStreetWest
ValleyViewRoad
CarriageHillsParkway Northeast
Texas AvenuePikeLakeT ra ilNortheastCounty Road 78 East
140thStreetNortheastChestnutBoulevardMcKennaRoad
Townline AvenueF ranklinTrailSoutheast150th Street West
Fairlawn AvenueMarschallRoad150thStreet Southeast
Eagle
Creek
A
venueFishPointRoadSoutheast
SunrayBoulevardSouthwestFrem ontA venueN o rth w estPanama AvenueN or t hwood RoadNorthwe s t
Egan Drive
Wood Duck Trail
CountryTrailWestOld Brick Yard Road154thSt reetNorthwest
LangfordBoulevard
LangfordAvenueMarystownRoadC o untyRoad18150th Street WestJohnsonMemorialDrive 130thStreetWest
Mystic Lake Drive SouthBaseline Avenue170th Street East
County Road 14
CountyRoad42East CountyRoad21C o u n try T r a i l EastZumbro AvenueCounty Road 79170th Street West
Ho
wa
r
dLake
RoadNort
h
west140thStreetNorthwest
McColl Drive
Scott County GIS
Legend
0 ¼
Miles
Source: Scott County, City of Prior Lake, MnGeo
!I
City Limits
Scott County Parcels
Existing Land Use (2017)
Agricultural
Commercial
Golf Course
Industrial
Institutional
Multifamily
Open Water
PUD
Park, Recreational, or Preserve
Public/Semi-Public
R-O-W
SMSC
Single Family Attached
Single Family Detached
Undeveloped
160th Street Southeast
MainAv e n ue Sou the a s t
Highway13SouthDuluthAvenueSoutheastEagleCreekAvenueSoutheast
AnnaTrailSoutheas
t FranklinTrailSoutheastDakot
a
S
t
r
e
e
t
S
o
u
t
h
e
a
s
t
Pleasant Street Southeast
ColoradoStreetSoutheast
Scott County GIS
Map Document: \\metrosouth1\gis\PLAK\T42112823\ESRI\Pro\112823_StoryMap\112823_CompPlan_Boards_2.0.aprx\112823_Future_Land_Use_11x17L Date Saved: 8/10/2017 12:21 PM2040 Comprehensive Plan
City of Prior Lake, MN August 2017
Future Lane Use
RevereWay160th Street Southeast
Highwa y 13South170thStreetSouthwes
t
ConnellyParkway
Highw
a
y
1
3
S
o
u
t
h
EagleCreekAvenueSouthe
a
stMarschall Road SouthMarschall Road SouthEagleCreekAvenueNortheastT u rnerD riveSo ut hwest BooneAvenueSouthMysticLakeDriveNorthwestHighway 13 South158thStreetWest
ValleyViewRoad
CarriageHillsParkway Northeast
Texas AvenuePikeLakeT ra ilNortheastCounty Road 78 East
140thStreetNortheastChestnutBoulevardMcKennaRoad
Townline AvenueF ranklinTrailSoutheast150th Street West
Fairlawn AvenueMarschallRoad150thStreet Southeast
Eagle
Creek
A
venueFishPointRoadSoutheast
SunrayBoulevardSouthwestFrem ontA venueN o rth w estPanama AvenueN or t hwood RoadNorthwe s t
Egan Drive
Wood Duck Trail
CountryTrailWestOld Brick Yard Road154thSt reetNorthwest
LangfordBoulevard
LangfordAvenueMarystownRoadC o untyRoad18150th Street WestJohnsonMemorialDrive 130thStreetWest
Mystic Lake Drive SouthBaseline Avenue170th Street East
County Road 14
CountyRoad42East CountyRoad21C o u n try T r a i l EastZumbro AvenueCounty Road 79170th Street West
Ho
wa
r
dLake
RoadNort
h
west140thStreetNorthwest
McColl Drive
Scott County GIS
Legend
0 ¼
Miles
Source: Scott County, City of Prior Lake, MnGeo
!I
City Limits
Scott County Parcels
Residential
Rural Density
Urban Low Density
Urban Medium Density
Urban High Density
Commercial
Retail/General Business
Town Center
Mixed Use District
Office/Industrial
Business Office Park
Planned Industrial
Public
Lake
Public/Semi-Public
Park, Recreational, or Preserve
Right-of-Way
Recreation & Open Space
SMSC
UEXA
160th Street Southeast
MainAv e n ue Sou the a s t
Highway13SouthDuluthAvenueSoutheastEagleCreekAvenueSoutheast
AnnaTrailSoutheas
t FranklinTrailSoutheastDakot
a
S
t
r
e
e
t
S
o
u
t
h
e
a
s
t
Pleasant Street Southeast
ColoradoStreetSoutheast
Scott County GIS
Prepared by: Bolton & Menk, Inc.
Water System Plan Update ǀ T21.113723
Appendix B: Well Hydrographs
840.00
845.00
850.00
855.00
860.00
865.00
870.00
875.00
880.00
885.00
Water Level Elevation (ft)Prior Lake Well No. 3 Water Elevation
Well Water Elevation Static Water Level*
*Note: Static water level measured on 4/14/1973
825.00
830.00
835.00
840.00
845.00
850.00
855.00
860.00
865.00
870.00
875.00
880.00
885.00
890.00
Water LEvel Elevation (ft)Prior Lake Well No. 4 Water Elevation
Well Water Elevation Static Water Level*
*Note: Static water level measured on 7/10/1995
700.00
725.00
750.00
775.00
800.00
825.00
850.00
875.00
900.00
925.00
Water Level Elevation (ft)Prior Lake Well No. 5 Water Elevation
Static Water Level*
*Note: Static water level measured on 4/6/1988
750.00
760.00
770.00
780.00
790.00
800.00
810.00
820.00
830.00
840.00
850.00
860.00
870.00
880.00
890.00
900.00
910.00
920.00
930.00
940.00
950.00
Water Level Elevation (ft)Prior Lake Well No. 6 Water Elevation
Well Water Level Static Water Level*
*Note: Static water level measured on 8/9/2001
740.00
760.00
780.00
800.00
820.00
840.00
860.00
880.00
900.00
Water Level Elevation (ft)Prior Lake Well No. 7 Water Elevation
Well Water Level Static Water Level*
*Note: Static water level measured on 4/14/2003
450.00
475.00
500.00
525.00
550.00
575.00
600.00
625.00
650.00
675.00
700.00
725.00
750.00
775.00
800.00
825.00
850.00
875.00
900.00
Water Level Elevation (ft)Prior Lake Well No. 8 Water Elevation
Well Water Level Static Water Level*
*Note: Static water level measured on 6/6/2006
450.00
475.00
500.00
525.00
550.00
575.00
600.00
625.00
650.00
675.00
700.00
725.00
750.00
775.00
800.00
825.00
850.00
875.00
900.00
Water Level Elevation (ft)Prior Lake Well No. 9 Water Elevation
Well Water Level Static Water Level*
*Note: Static water level measured on 10/12/2006
Prepared by: Bolton & Menk, Inc.
Water System Plan Update ǀ T21.113723