HomeMy WebLinkAbout01 23 2017 Joint Water Treatment Facility Discussion ReportPhone 952.447.9800 / Fax 952.447.4245 / www.cityofpriorlake.com
4646 Dakota Street SE
Prior Lake, MN 55372
CITY COUNCIL WORK SESSION REPORT
MEETING DATE: JANUARY 23, 2017
AGENDA #: C
PREPARED BY: FRANK BOYLES, CITY MANAGER
KATY GEHLER, PUBLIC WORKS & NATURAL RESOURCES
DIRECTOR
DON URAM, FINANCE DIRECTOR
PRESENTED BY: FRANK BOYLES, KATY GEHLER, AND DON URAM
AGENDA ITEM:
DISCUSSION:
COLLABORATIVE WATER TREATMENT AGREEMENT
Introduction
The purpose of this agenda item is to have the City Council provide
feedback on a collaborative water treatment agreement with the Shakopee
Mdewakanton Sioux Community (SMSC).
History
The City has been planning long range water supply needs that include the
need for additional water source (wells), treatment and storage. As the
City is reaching its capacity with the existing facilities, an evaluation was
completed to review the future demands and timing of critical infrastructure
to ensure these needs can be met. (See attached Bolton and Menk
Report).
There are currently seven wells that provide the water supply for the City of
Prior Lake. Of the seven wells, six of them are pumped to the City’s water
treatment plant where iron and manganese are removed before being
distributed. The total firm pumping capacity to the WTP is 5.26 MGD.
In 2010 the demands in the system indicated a need for additional water
and the City considered the construction of another supply well to feed the
water treatment plant. Before the well was drilled, various other options
were considered including entering into a partnership with the Shakopee
Mdewakanton Sioux Community (SMSC) as they also had needs to
provide redundancies in their system as well.
Ultimately it was found to be more cost effective for both entities to move
forward with a joint project. The current water agreement allows the City to
purchase up to 1.2 MGD and has allowed the City to postpone the
construction of another well for the time being.
As the City continues to develop it is projected that there will be a need for
additional water supply, including treatment, source and storage. In the
long-range water planning documents the City has always envisioned
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these needs being met with additional facilities in the western portion of the
City near Spring Lake Park and the Campbell Lake area.
Based on the current projections, the additional improvements should be
operational by the end of 2019 when the demands are expected to reach
6.95 MGD (which will exceed the capacity of our wells and treatment plant)
and continue to grow from there. To meet the future needs of the City a
new water treatment plant, two source wells, and storage were
programmed into the Capital Improvement Plan (CIP) in 2019.
Significant planning and preparation are required for these types of
facilities. Permitting (Minnesota Department of Health (MDH), Minnesota
Department of Natural Resources (DNR), water appropriations, etc.) is
needed along with the design and construction of the facility. The total
process can take five years or more. Now is the time to move forward to
ensure the City has an adequate water supply in the future.
As the City began to look to provide for the future needs, an opportunity
arose to expand on the existing water partnership with the SMSC. The
SMSC also has a need to replace and expand aging treatment systems
and has a desire to locate a new facility south of CR82 near Spring Lake.
The SMSC intends to have this new plant online by 2019 and is starting the
design process this year.
The two entities undertook a study to evaluate the future needs of the two
communities and consider options to provide those needs. The results of
this study were provided to the City Council at a work session on June 27,
2016. While some council members had the opportunity to view the
PowerPoint recently, this is a good document for all councilors to review
(see attached).
The study considered the options of having each entity construct and
operate separate facilities or partnering on a joint facility. Mostly due to
redundancies that must be designed into each of these types of facilities,
there is significant cost savings with a joint facility. In the case of the SMSC
the savings is estimated to be $3.4 million. In the case of Prior Lake, the
estimated cost reduction is $ 6.2 million.
A joint facility would include iron and manganese removal for both entities,
reverse osmosis for the SMSC and ground storage. Initially the WTP could
be supplied by the three existing wells SMSC owns and Well # 6 for the
City. Each entity would be responsible for extending watermain from their
well(s) to the WTP.
During the work session there was some discussion regarding the
ownership of future supply wells. There was no regulatory benefit to having
the SMSC own all of the wells. By having the City own the future supply
wells, it provides balance to the partnership. With this type of
arrangement, three water rates would be defined within the agreement to
allow the most flexibility with the partnership:
3
1. The City purchasing raw water and treatment from the SMSC
(current arrangement)
2. The City purchasing water treatment only from the SMSC
(Supplying the raw water from City owned and operated wells)
3. The SMSC purchasing raw water from the City
On July 11, 2016 the council adopted the attached resolution formally
indicating support for a collaborative water supply arrangement and
authorized staff to begin negotiating an agreement.
Current Circumstances
City and SMSC staff have met numerous times to discuss the agreement.
At first it was our belief that we could basically take large sections of the
existing joint water agreement and use them wholesale for this document.
This approach has proved to be beneficial for certain “boilerplate”
paragraphs like indemnification, data practices, defining employees,
examination of the plant and the like. However, there are several
fundamental differences in this agreement which have required a great
deal of consideration, discussion, and rewriting.
Earlier this week we received a draft joint water treatment plant agreement
from the SMSC. City staff examined it and made numerous revisions and
additions. It did not seem appropriate or productive to share with the
council a draft agreement that SMSC Staff has not seen. When a draft is
available that both parties have had input in, we will share it with the city
council.
Below is a summary of the key issues which deserve city council attention.
It would be helpful if the city council provided conceptual input rather than
drafting document language. That is a function best left to the attorneys.
Responsibilities
Design and Construction The SMSC will be responsible for the design
and construction of the facility with
appropriate approvals for the City at key
points in the process.
Operation The SMSC will own and operate the plant.
The City and SMSC will enter into a
separate operational agreement that
ensures minimal run times on the three
plants such that treatment is efficient and
optimized. The SCADA systems will be
programed to ensure compliance with this
agreement. In addition, the City will have
the right to enter the property both for
emergencies and as requested to meet all
state agency access requirements.
4
Water Allocation
Perpetual Right The City will have a perpetual right to
treatment of water at the allocation noted in
the agreement.
Allocation Amount The agreement will allow for water treatment
up to 2.1 million gallons per day (MGD).
Initial water supply will come from Well 6
(1,200 gpm) for a total of capacity of 1.7
MGD. Additional capacity can be added by
drilling new city wells in the annexation area.
Payments
Permanent Assets/
Intangible Asset
The City’s share of the permanent assets
(construction costs) is estimated to be
$9.968 million (includes engineering, admin,
legal). The City will make fixed annual
payments for 25 years financed at 3%.
Operation, Maintenance
and Replacement
Actual cost of materials, services, and staff
time to operate and maintain the Prior Lake
portion of the treatment plant paid at a rate
per 1,000 gallons actually pumped. Fixed
for first five years of the agreement with
annual review and adjustment thereafter just
like the water use agreement.
Permanent Asset
Replacement
Addresses financing or reserve of funds for
future replacements or expansions not
accounted for in the OM&R.
Enforcement and Remedy
Limited Waiver of
Sovereign Immunity
SMSC has indicated a willingness to provide
a limited waiver of sovereign immunity in lieu
of a cash escrow. Should the SMSC default
on the agreement, the City would have the
right to bring suit against the SMSC in Scott
County District Court using Minnesota Laws
specially related to this agreement.
Option B for Default If the SMSC does not agree to a limited
waiver of sovereign immunity, the other
remedy option for default is the use of an
escrow account. In this option the SMSC
would establish an escrow account which
will increase annually to equal the amount of
the City’s Fixed payments. These funds
would be available to the City in case of an
SMSC default.
Other
Term The agreement has perpetual term.
Termination Termination of the agreement must be
mutually agreed upon.
Annexation Area The agreement will address SMSC purchase
of land in the City’s comprehensively
5
planned areas for annexation and
development. Acreage and connection fees
collected during development of this area
are anticipated to fund the annual fixed
payments. In the event of SMSC purchase
of property in the annexation area which
diminishes the city’s capacity to pay water
treatment plant capital charges the city will
receive a credit commensurate with the
development fees due or the SMSC would
make the actual development fee payment
for the land.
Staff will review the terms of the agreement with the Council during the
work session and seek feedback that will shape the remaining
negotiations.
ISSUES: Premised on mutually assured destruction
The agreement will be premised on the theory of mutually assured
destruction meaning neither party will be able to back out easily due to the
extensive investments. Both parties have expressed a strong interest in
wanting this joint plant to work in perpetuity.
In the case of the City, we will rely on the water treatment provided by the
SMSC. If we were to default, the City would have to repay the capital, and
then rebuild a separate more expensive treatment plant on land most likely
in the annexation area if any remains undeveloped in the correct location
Contrarily, the SMSC is taking on the cost burden of financing close to $10
million of assets for the City. If they were to default on the agreement by
not providing water, they would not receive payment for assets that they
will not have need for in the 20-year planning horizon.
Timing
The SMSC has indicated a desire to have the new WTP online by the
spring of 2019 to meet their projected needs. This timeline corresponds to
the City’s projections of when additional treatment capacity will be needed.
Considering a projected 20+ months of construction, 4-6 months of design,
and 6 weeks of regulatory agency review, the process needs to begin very
soon.
FINANCIAL
IMPACT:
Planning level cost estimated were completed for the two main options,
separate facilities and a joint facility. The table below summarizes these
estimated costs and notes the savings to each community.
6
Construction Cost Comparison
Estimated
Construction
Cost
Community’s
Share of Joint
Facility
Total Savings
with Joint
Facility
SMSC $14,200,000 $10,804,238 $3,395,762
Prior Lake $14,857,500 $8,668,013 $6,189,487
Joint $19,472,250
City financing of this project is proposed to come from revenues collected
from new development including the Trunk Water acreage charge, the
Water Tower charge, and water connection charges. The Trunk Water
charge is a per acre charge that is paid at time of development while the
Water Tower charge and water connection charges is per unit fee that is
paid at time of building permit. These revenues are deposited into the
Trunk Reserve and the Water Storage Funds to pay for future water
infrastructure including trunk water mains, water storage facilities, and
major facility additions such as wells, booster stations and a new water
treatment plant.
The 2004 Water Plan Update identified several improvements necessary to
provide water service to the west and southern sections of the City that the
proposed joint water treatment plant facility would cover. As a result, it is
appropriate to use the revenues collected in both the Trunk fund and the
Water Storage fund pay for the City’s share of the cost of the facility.
Per the draft agreement, the City’s fixed charge would be approximately
$500,000 a year for 25 years. Based on current projections of 120 single-
family permits per year, revenues collected would total approximately
$200,000 in the Water Storage fund and $500,000 in the Trunk fund. In
addition, there is approximately $1.5 million in the Water Storage fund.
Staff recommends that these funds be kept in reserve to cover any
shortfalls in actual development fee revenue.
The amount available to contribute towards the joint facility in each of the
trunk funds will be determined annually based on the City’s Capital
Improvements Plan, the level of development activity, and existing and
projected cash balances. If revenue is not available in the trunk fund to
meet the fixed payment, the Water fund will be the secondary funding
source.
Conclusion
We believe that SMSC Staff will be present at the work session. We will
lead the council through the PowerPoint if desired. Following that, it would
be helpful to review the various issues identified in this report together
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with any other issues the council desires to discuss in order that we can
continue to work with the SMSC to fashion an agreement which is
satisfactory to both parties.
Water System Evaluation:
South Service Area
A joint study between the Shakopee Mdewakanton
Sioux Community and the City of Prior Lake
C15.110719
June 14, 2016
Submitted by:
Bolton & Menk, Inc.
12224 Nicollet Avenue
Burnsville, MN 55337
P: 952-890-0509
F: 952-890-8065
Water System Evaluation
for
Shakopee Mdewakanton Sioux Community
&
City of Prior Lake
Prior Lake, MN
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
License No. 26468
Date: June 14, 2016
BOLTON & MENK, INC.
CONSULTING ENGINEERS AND LAND SURVEYORS
SMSC/Prior Lake, MN – C15.110719 Page TOC-i
Water System Evaluation Prepared by Bolton & Menk, Inc.
TABLE OF CONTENTS
EXECUTIVE SUMMARY .......................................................................................................................... 1
SECTION 1 INTRODUCTION .............................................................................................................. 1-1
A. PURPOSE ..................................................................................................................................... 1-1
B. BACKGROUND .......................................................................................................................... 1-1
C. REPORT ORGANIZATION ........................................................................................................ 1-1
SECTION 2 WATER DEMAND ............................................................................................................ 2-1
A. CURRENT AND FUTURE WATER DEMAND FOR SMSC .................................................... 2-1
B. CURRENT WATER DEMAND FOR THE CITY OF PRIOR LAKE ........................................ 2-2
C. FUTURE DEMANDS FOR THE CITY OF PRIOR LAKE ........................................................ 2-3
SECTION 3 EVALUATION OF EXISTING FACILITIES ................................................................... 3-1
A. SMSC ............................................................................................................................................ 3-1
1. Water Supply .......................................................................................................................... 3-1
2. Treatment Capacity ................................................................................................................ 3-1
3. Storage .................................................................................................................................... 3-2
4. Summary ................................................................................................................................ 3-2
B. THE CITY OF PRIOR LAKE ...................................................................................................... 3-3
1. Water Supply .......................................................................................................................... 3-3
2. Treatment Capacity ................................................................................................................ 3-4
3. Storage .................................................................................................................................... 3-4
4. Summary ................................................................................................................................ 3-5
SECTION 4 EVALUATION OF ALTERNATIVES .............................................................................. 4-1
A. GENERAL .................................................................................................................................... 4-1
B. WATER SUPPLY ........................................................................................................................ 4-1
C. WATER TREATMENT AND STORAGE .................................................................................. 4-2
D. WATER ALLOCATIONS ........................................................................................................... 4-2
1. Separate Facilities................................................................................................................... 4-2
2. Joint Facility – City Wells ...................................................................................................... 4-5
3. Joint Facility – No City Well ................................................................................................. 4-8
SECTION 5 COST ESTIMATE & PROPOSED IMPLEMENTATION ................................................ 5-1
A. GENERAL .................................................................................................................................... 5-1
B. COST ESTIMATE........................................................................................................................ 5-1
C. PROJECT FINANCING ............................................................................................................... 5-2
D. IMPLEMENTATION SCHEDULE ............................................................................................. 5-4
SECTION 6 ADDITIONAL CONSIDERATIONS ................................................................................ 6-1
A. GENERAL .................................................................................................................................... 6-1
B. REGIONAL WATER SUPPLY PLANNING .............................................................................. 6-1
C. WATER CONSERVATION ........................................................................................................ 6-1
1. Irrigation Practices ................................................................................................................. 6-1
2. Educational Efforts ................................................................................................................. 6-1
D. ADDITIONAL WATER SOURCES ........................................................................................... 6-2
1. Storm Water for Irrigation ...................................................................................................... 6-2
SMSC/Prior Lake, MN – C15.110719 Page TOC-ii
Water System Evaluation Prepared by Bolton & Menk, Inc.
LIST OF TABLES
Table
Number
Page
ES.1 Construction Cost Comparison 2
ES.2 Operating Expenses and Bond Payments 3
ES.3 Implementation Schedule – Joint Water Treatment Facility 3
2.1 5 Year Prior Lake Historical Water Demands 2-3
2.2 Prior Lake Projected Future Treated Water Demands 2-5
3.1 South WTP Capacity Evaluation 3-2
3.2 SMSC Water Treatment Plant Evaluation Overview 3-3
3.3 Prior Lake Well Information 3-3
3.4 Prior Lake Well Pumping Capacity to WTP 3-4
3.5 Prior Lake Water Treatment Plant Evaluation Overview 3-5
4.1 Projected Raw Water Supply With New SMSC and Prior Lake Wells 4-8
4.2 Projected Raw Water Supply With New SMSC Wells 4-9
5.1 Estimated Construction Costs – Water Treatment Facility 5-1
5.2 Estimated Construction Costs Breakout – Joint Water Treatment Facility 5-2
5.3 Equipment Replacement Funds – Joint Water Treatment Facility 5-3
5.4 Operating Expenses and Bond Payments 5-4
5.5 Implementation Schedule – Joint Water Treatment Facility 5-4
SMSC/Prior Lake, MN – C15.110719 Page 1
Water System Evaluation Prepared by Bolton & Menk, Inc.
EXECUTIVE SUMMARY
The purpose of this report is to evaluate the water supply and treatment needs for the South
Service Area of the Shakopee Mdewakanton Sioux Community (SMSC) and the City of Prior
Lake. Current and future needs of both the SMSC South Service Area and the City of Prior Lake
make a joint water project feasible. Future demands in the City of Prior Lake are projected to
increase, leading to more water usage.
Prior Lake currently has a treatment plant that is designed to treat up to 7.5 MGD of raw water,
including the 1 MGD purchased from SMSC. However, unexpected issues with well water
supplies have resulted in a shortage of raw water supplies to the treatment facility. The City of
Prior Lake has a deficit of 2.24 MGD or 1,556 gpm of well water supply. The City of Prior Lake
is projected to see a significant increase in water demand within the next 20 years. By 2036, the
projected peak day demand is 9.6 MGD. Additional water sources are needed to meet projected
demands.
The South Service Area Water Treatment Facility receives water from three different wells with
a total capacity of 2,050 gpm (2.46 MGD) and a firm capacity of 1,350 gpm (1.62 MGD). There
is a sufficient well water supply to meet current demands. The existing water treatment plant
filters have a total and firm capacity of 1.98 and 1.2 MGD, respectively. The existing RO units
have total and firm capacities of 1.98 and 1.32 MGD, respectively. The SMSC South WTP has
the capacity to meet current peak day demands. However, there are deficiencies in the WTP firm
capacity for projected peak day with both the Enterprise Addition plus ICO subdivision
including irrigation demand and excluding it. To meet the projected demands, a new RO unit,
and well is needed.
One option to provide a stable treated water source to each community is to construct separate
facilities. A new SMSC South WTP would operate for 20 hours per day and have a treatment
capacity of 2.64 MGD with a firm capacity of 1.98 MGD. SMSC would route existing wells 6, 8
and 10 to a new treatment facility and connect Well No. 9 (capacity of 700 gpm). Therefore, no
new wells would need to be drilled for SMSC.
A new treatment plant for Prior Lake would be designed based on the difference between the
projected peak day demand of 9.6 MGD and the current treatment capacity of 7.5 MGD. A new
SMSC/Prior Lake, MN – C15.110719 Page 2
Water System Evaluation Prepared by Bolton & Menk, Inc.
separate Prior Lake water treatment facility would operate for 20 hours per day and be designed
to treat 2.1 MGD. To meet the demand of a new treatment facility and firm capacity
requirements, Prior Lake will have to connect Well No. 6, that provides 1,200 gpm, and install
two additional wells capable of producing at least 900 gpm each.
Another option is to construct a joint water treatment facility and treat water to send to both
SMSC and Prior Lake. This requires both SMSC and Prior Lake to provide well water to the
treatment plant. A combined treatment plant would be designed to treat 4.74 MGD and would
operate for 20 hours per day to allow for backwash and maintenance. This option requires Prior
Lake to connect Well No. 6 at 1,200 gpm, and drill two additional wells capable of producing
900 gpm each. SMSC would need to connect Wells 6, 8, 9, and 10, bringing the total well
capacity to 5,850 gpm (7.02 MGD) and a firm capacity of 4,650 gpm (5.58 MGD).
A final option is to construct a joint facility, use the existing SMSC wells and Prior Lake Well
No. 6. A combined treatment plant would be designed to treat up to 4.74 MGD. Prior Lake
would connect Well No. 6 capable of producing 1,200 gpm, but no other Prior Lake wells would
be connected. SMSC would connect Wells 6, 8, 9, and 10 to a new treatment facility. However,
to meet firm capacity, the capacity with the largest well out of service (Prior Lake Well No. 6),
SMSC will need to redevelop Well No. 9 to produce at least 1,200 gpm. With Prior Lake Well
No. 6 and SMSC Well No. 9 capable of producing 1,200 gpm, the total well capacity would be
5,150 gpm (6.18 MGD) with a firm capacity of 3,950 (4.74 MGD) with either Well No. 6 or No.
9 offline.
The estimated construction costs to construct the water treatment facilities as discussed above
and as presented in Table 5.1 is presented in Table ES.1 along with each community’s share and
total savings of the joint water treatment facility.
Table ES.1
Construction Cost Comparison
Estimated
Construction Cost
Community’s
Share of Joint
Facility
Total Savings with
Joint Facility
SMSC $14,200,000 $10,804,238 $3,395,762
Prior Lake $14,857,500 $8,668,013 $6,189,487
Joint $19,472,250
SMSC/Prior Lake, MN – C15.110719 Page 3
Water System Evaluation Prepared by Bolton & Menk, Inc.
Based on the City of Prior Lake receiving a minimum of 1,200,000 gallons per day (438 million
gallons per year) of treated water from the new joint WTP, the annual anticipated payment from
the City of Prior Lake is $810,300. The breakout of operating expenses and bond payments are
shown in Table ES.2. Should the City use more than the 438 million gallons annually, the
additional charge for treated water would only include the cost of OM&R, power and chemicals.
Table ES.2
Operating Expenses and Bond Payments
Expense Item Cost per 1,000 Gallons
OM&R Costs $0.18
Electrical Costs $0.25
Chemical Costs $0.28
Bond Payment Costs $1.14
Total Costs $1.85
A proposed implementation schedule for the joint water treatment plant is presented in
Table ES.3.
Table ES.3
Implementation Schedule
Joint Water Treatment Facility
ITEM DATE
1. Presentation to Both Councils June 2016
2. Approve Study and Cost Sharing Agreement September 2016
3. Prepare Plans and Specifications October – December 2016
4. Review and Approval of Contract Documents January – February 2017
5. Project Construction April 2017 – November 2018
SMSC/Prior Lake, MN – C15.110719 Page 1-1
Water System Evaluation Prepared by Bolton & Menk, Inc.
SECTION 1 INTRODUCTION
A. PURPOSE
The purpose of this report is to evaluate the water supply and treatment needs for the
South Service Area of the Shakopee Mdewakanton Sioux Community (SMSC) and the
City of Prior Lake. This report will provide the City with necessary information regarding
water supply and treatment needs. They can utilize the information gathered here to make
an informed decision on the possible expansion of their water supply system.
B. BACKGROUND
Current and future needs of both the SMSC South Service Area and the City of Prior
Lake make a joint water project feasible. Future demands in the City of Prior Lake are
projected to increase, leading to more water usage. Projections for water usage indicate
that the Water Treatment Facility will be operating near capacity with limited storage
space. The City of Prior Lake is lacking enough well water supply to keep up with
current and future demands. A joint project between SMSC and the City of Prior Lake
may be a cost effective alternative to solve both communities’ water supply problems.
C. REPORT ORGANIZATION
To adequately address the major issues for the Prior Lake water system, this report is
organized into six sections. Section 2 reviews the current and future water demands.
Section 3 provides an evaluation of the existing facilities. Evaluation of the alternatives is
provided in section 4. Section 5 introduces cost estimates and the proposed
implementation schedule, while section 6 discusses additional considerations.
SMSC/Prior Lake, MN – C15.110719 Page 2-1
Water System Evaluation Prepared by Bolton & Menk, Inc.
SECTION 2 WATER DEMAND
A. CURRENT AND FUTURE WATER DEMAND FOR SMSC
The water demand for the Enterprise Addition can be estimated by using the
Metropolitan Council Environmental Services (MCES) criteria, which provides factors to
convert non-residential facilities into equivalent residential units (SAC units). It is
assumed that the water demand for the Enterprise Addition would be essentially equal to
the sanitary sewer flow as the irrigation needs for this area are provided by SMSC’s
water reuse system. Following are the pertinent MCES criteria:
Convention Center - 14 people = 1 SAC unit, 286 SAC units based on 4,000
people
Hotel - 2 rooms = 1 SAC unit, 100 SAC units based on 200 rooms
1 SAC unit = 274 gallons per day (gpd)
Total peak day water demand = 386 SAC units x 274 gpd/unit = 105,764 gpd
or 74 gpm
The above water demand calculation is based on full capacity of both the hotel addition
and convention center and is therefore considered the peak day demand. The 74 gpm
water demand shown above is the average over a 24 hour period. Water demand is not
uniform and the peak hour demand rate as estimated by the Enterprise Addition
planners/designers is 382 gpm.
The Inyan Ceyaka Otonwe (ICO) subdivision water demand needs to be considered in
evaluating water system impacts. The following criteria obtained from SMSC north
residential historic water use are used in estimating this demand.
Single family residential average demand = 750 gpd
Townhome demand = 375 gpd (assumed)
Total average day water demand = 67,500 gpd (based on full development)
Peak factor = 3.42
Peak day demand = 3.42 x 67,500 gpd = 230,850 gpd or 160 gpm
The above water demands for the ICO subdivision are based on the lawn irrigation water
being supplied by the potable water system. If the irrigation demand would be supplied
by a water reuse system, the water demand is estimated as follows:
SMSC/Prior Lake, MN – C15.110719 Page 2-2
Water System Evaluation Prepared by Bolton & Menk, Inc.
Single family residential average demand = 475 gpd
Townhomes = 275 gpd
Total average day water demand = 43,800 gpd (based on full development)
Peak factor = 2.0 (estimated)
Peak day demand = 2.0 x 43,800 gpd = 87,600 gpd or 61 gpm
The peak day demand is significantly reduced when the ICO irrigation demand is
removed.
Combining the water demands for the Enterprise Addition and the ICO subdivision
results in the following:
Peak day demand = 337,000 gpd with ICO irrigation demand
Peak day demand = 194,000 gpd without ICO irrigation demand
B. CURRENT WATER DEMAND FOR THE CITY OF PRIOR LAKE
The historical water demands for the City of Prior Lake are presented in Table 2.1.
Average per capita demand for the past five years is 88.8 gal/cap-d (gpcd) with an
average peaking factor of 2.85. The historical trends indicate a slight increase in the
peaking factor. However, the average day demand has decreased since 2010 from 2.1
MGD to 1.39 MGD is 2015. The peak day demand since 2010 occurred in 2012 and was
6.61 MGD, exceeding the water treatment facilities capacity of 6.48 MGD.
To increase capacity, the City of Prior Lake began purchasing water from the Shakopee
Mdewakanton Sioux Community in 2014. The agreement between SMSC and the City of
Prior Lake allows the City to purchase 1.0 MGD of treated water. The Water Treatment
Facility has the capacity to handle a total of 7.5 MGD, with the 1 MGD purchased from
SMSC.
SMSC/Prior Lake, MN – C15.110719 Page 2-3
Water System Evaluation Prepared by Bolton & Menk, Inc.
C. FUTURE DEMANDS FOR THE CITY OF PRIOR LAKE
Historical water usage was analyzed to project the future demand for the City of Prior
Lake. Population projections were used as the basis for water demand in the future. An
average per-capita usage of 88.8 gpcd from the historical water usage was used to project
future average day water demand. Peaking factors can remain relatively consistent over
several years. A peaking factor too large will overestimate the peak day demand, while a
peaking factor too low will not yield accurate peak day demands. Since peaking factors
do not change significantly, it is acceptable to take the average peaking factor for a period
of years to project peak day demands in the future. The peaking factor for future years
used to project the peak demand was 2.85.
Currently, the water treatment plant has a capacity of 6.48 MGD. The agreement between
SMSC and Prior Lake allows the City to purchase 1 MGD of treated water, for a total
treatment capacity of 7.5 MGD. Table 2.2 projects future water usage based on historical
trends. The future projections indicate the City of Prior Lake can expect to use more than
1 million gallons of water per day by the year 2026. By 2040, the City of Prior Lake is
estimated to use 1.3 million gallons of water per day.
Table 2.1: 5 Year Prior Lake Historical Treated Water Demands
Year Population Total Water
usage (1000 gal)
Peak
Day
(MGD)
Average
Day
(MGD)
Customer
water usage
(gpcd)
Peaking
Factor
2010 22,796 769,227 5.54 2.10 92.4 2.64
2011 23,010 754,934 5.00 2.22 89.9 2.25
2012 23,385 894,580 6.61 2.35 104.8 2.81
2013 24,223 792,697 6.12 1.98 89.7 3.09
2014* 24,911 714,777 5.10 1.58 78.6 3.23
2015* 24,732 638,984 4.25 1.39 77.4 3.06
Average 760,867 5.44 1.94 88.8 2.85
Maximum 894,580 6.61 2.35 104.8 3.23
*2014 and 2015 include purchased water from SMSC
SMSC/Prior Lake, MN – C15.110719 Page 2-4
Water System Evaluation Prepared by Bolton & Menk, Inc.
One way to analyze a water system is to look at the current treatment capacity and
calculate the remaining treatment capacity based on future water usage projections. Based
on these future projections and current treatment capacity, the remaining treatment
capacity for each year can be calculated by subtracting the peak day demand from the
total treatment capacity.
The total treatment capacity for Prior Lake is 7.5 MGD, including water purchased from
SMSC. The treatment capacity for Prior Lake is limited by the well water supply. With
the current well water supply and operating the wells for 20 hours per day, the total raw
waters supply is 5.82 MGD. The surplus or deficit of treatment capacity is determined by
adding the well water supply to the 1 MGD purchased from SMSC, then subtracting that
from the projected peak day demand. By 2020, Prior Lake can expect to have a deficit in
water treatment capacity of 0.13 MGD. The remaining treatment capacity significantly
drops each year. Future projections indicate that by 2024, the City of Prior Lake will have
a deficit in treatment capacity of 0.78 MGD. The deficit of water treatment capacity
increases to 1.75 MGD by 2030 and to 3.42 MGD by 2040. It is critical to evaluate
options to increase current treatment capacity to reduce the water treatment deficit.
Analyzing the storage capacity and future water usage can help predict when storage
capacity will run out. The City of Prior Lake currently has 3.25 MGD of storage capacity
in elevated storage and within the treatment facility. The remaining average day storage
capacity must be equal to or greater than the average day demand. For future water
demand projections, the remaining average day storage capacity can be calculated by
subtracting the average day demand from the current storage capacity of 3.25 MGD.
Based on these calculations, by 2020 the City of Prior Lake will have 0.81 MGD of
storage capacity for the average day demand. By 2030, this number decreases to 0.24
MGD. The future projections indicate that there will be a storage capacity deficit of 0.05
MGD by 2035 and a deficit of 0.35 MGD by 2040. Evaluation of storage capacity based
on future projections is critical to maintain storage for future years. These predictions are
shown in Table 2.2 below.
SMSC/Prior Lake, MN – C15.110719 Page 2-5
Water System Evaluation Prepared by Bolton & Menk, Inc.
Table 2.2: Prior Lake Projected Future Treated Water Demands
Population
Projections Projected Total
Water used per year
(1,000 gal)
Projected
Average Day
Demand
(MGD)
Projected
Peak Day
Demand
(MGD)
Remaining
Treatment
Capacity
(MGD)
Remaining
Average Day
Storage
Capacity
(MGD)
Year Population
2016 25,286 819,506 2.25 6.39 0.43 1.00
2017 25,839 837,448 2.29 6.53 0.29 0.96
2018 26,393 855,390 2.34 6.67 0.15 0.91
2019 26,946 873,332 2.39 6.81 0.01 0.86
2020 27,500 891,274 2.44 6.95 -0.13 0.81
2021 28,140 912,017 2.50 7.11 -0.29 0.75
2022 28,780 932,759 2.56 7.27 -0.45 0.69
2023 29,420 953,501 2.61 7.44 -0.62 0.64
2024 30,060 974,244 2.67 7.60 -0.78 0.58
2025 30,700 994,986 2.73 7.76 -0.94 0.52
2026 31,340 1,015,729 2.78 7.92 -1.10 0.47
2027 31,980 1,036,471 2.84 8.08 -1.26 0.41
2028 32,620 1,057,213 2.90 8.25 -1.43 0.35
2029 33,260 1,077,956 2.95 8.41 -1.59 0.30
2030 33,900 1,098,698 3.01 8.57 -1.75 0.24
2031 34,560 1,120,089 3.07 8.74 -1.92 0.18
2032 35,220 1,141,479 3.13 8.90 -2.08 0.12
2033 35,880 1,162,870 3.19 9.07 -2.25 0.06
2034 36,540 1,184,260 3.24 9.24 -2.42 0.01
2035 37,200 1,205,651 3.30 9.40 -2.58 -0.05
2036(1) 37,860 1,227,042 3.36 9.57 -2.75 -0.11
2037 38,520 1,248,432 3.42 9.74 -2.92 -0.17
2038 39,180 1,269,823 3.48 9.90 -3.08 -0.23
2039 39,840 1,291,213 3.54 10.07 -3.25 -0.29
2040 40,500 1,312,604 3.60 10.24 -3.42 -0.35
(1) Design Year
*Population estimates based on Met Council System Statements
*Remaining treatment capacity based on current well supply and water purchased from SMSC
*Remaining storage capacity based on current 3.25 MGD storage capacity
SMSC/Prior Lake, MN – C15.110719 Page 3-1
Water System Evaluation Prepared by Bolton & Menk, Inc.
SECTION 3 EVALUATION OF EXISTING FACILITIES
A. SMSC
1. Water Supply
Currently, SMSC receives water at the South facility from three different wells: Well No.
6, 8, and 10. These wells have capacities of 700, 650, and 700 gpm, respectively. An
additional well, Well No. 9, has a capacity of 800 gpm but is not connected to the
treatment facility. The total capacity for the three wells connected to the treatment facility
is 2,050 gpm with a firm capacity of 1,350 gpm. The wells provide adequate water supply
to the treatment plant for current demands. The existing wells are in good condition and
should provide an adequate water supply for several more years.
2. Treatment Capacity
Both the Enterprise Addition and the ICO subdivision will receive water supply from the
South System Water Treatment Plant (WTP) on Sioux Trail. The WTP must have
capacity to accommodate peak day demand. The peak day demand in 2014 was 954,000
gpd. This is the highest day demand since the water reuse system started providing the
irrigation water. Combining this peak day with the projected peak day for the Enterprise
Addition and ICO subdivision results in the following:
Projected peak day demand = 1,291,000 gpd with ICO irrigation demand
- Add 20% contingency = 1,549,000 gpd
Projected peak day demand = 1,148,000 gpd without ICO irrigation demand
- Add 20% contingency = 1,378,000 gpd
The twenty percent contingency amount is added to provide an allowance for other
increases in water demand, including increased laundry usage resulting from the
Enterprise Addition.
The WTP must have adequate capacity to accommodate the peak day demand. The
capacity is typically based on the supply wells and filters operating 20 hours per day. It is
also based on the largest individual unit of each type not included. This provides
redundancy if any single unit is out of operation and is referred to as firm capacity.
Table 3.1 shows both the full capacity and firm capacity of the water supply and
treatment components and compares it with the projected peak day demand.
SMSC/Prior Lake, MN – C15.110719 Page 3-2
Water System Evaluation Prepared by Bolton & Menk, Inc.
Table 3.1: South WTP Capacity Evaluation
WTP
Components
Full
Capacity
(gpd)
Firm
Capacity
(gpd)
Projected
Peak Day
w/ ICO Irr.
Demand
(gpd)
Reserve
Capacity
(gpd)
Projected
Peak Day
w/o ICO Irr.
Demand
(gpd)
Reserve
Capacity
(gpd)
Wells 2,460,000 1,620,000 1,549,000 71,000 1,378,000 242,000
Filters 1,920,000 1,200,000 1,549,000 -349,000 1,378,000 -178,000
Reverse
Osmosis
(RO) Units
1,980,000 1,320,000 1,549,000 -229,000 1,378,000 -58,000
This table shows that the WTP can comfortably accommodate the current peak demand
of 954,000 gpd at firm capacity. However, it also shows deficiencies in the WTP firm
capacity for projected peak day with both the Enterprise Addition plus ICO subdivision
including irrigation demand and excluding it. The WTP currently has three wells, three
filters, and three RO units. Increasing the WTP capacity would involve adding a fourth
filter and fourth RO unit. This would increase the capacity to 1,980,000 gpd. This would
accommodate the project peak day and provide an allowance for future growth. Adding
the filter and RO unit would trigger the need for another well or connecting Well No. 9.
3. Storage
The existing water storage tanks have reserve capacity to accommodate the Enterprise
Addition and the ICO subdivision.
4. Summary
Table 3.2 provides a brief overview of the system evaluation for the SMSC South Service
Area Water Treatment Plant.
SMSC/Prior Lake, MN – C15.110719 Page 3-3
Water System Evaluation Prepared by Bolton & Menk, Inc.
Table 3.2
SMSC Water Treatment Plant Evaluation Overview
System Component Comments
1. Water Supply Existing well capacity is sufficient for current demands.
New well needed with a plant expansion.
2. Water Treatment Current treatment capacity is adequate for current
demands. More capacity needed with increased growth.
3. Water Storage Water storage facilities are adequate to meet current
demands.
B. THE CITY OF PRIOR LAKE
1. Water Supply
The City of Prior Lake receives water from eight different wells. A summary of the raw
water well capacity is presented in Table 3.3. Well number six is not currently connected
to the water treatment plant.
Table 3.3
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
Pumping Rate (gpm) 1050 950 750 N/A 450 1200 450
Unexpected issues with new well water supplies have resulted in a shortage of raw water
supplies to the treatment facility. Analysis of the existing wells indicates that the total
capacity for the wells is 4,850 gallons per minute, with a firm capacity of 3,650 gallons
per minute. The firm capacity is the capacity with the largest well out of service. A
summary of the raw water capacity deficit for the City of Prior Lake is presented in
Table 3.4.
SMSC/Prior Lake, MN – C15.110719 Page 3-4
Water System Evaluation Prepared by Bolton & Menk, Inc.
Table 3.4
Prior Lake Well Pumping Capacity to WTP
20-Hour Pumping 24-Hour Pumping
Firm
Capacity
Total
Capacity
Firm
Capacity
Total
Capacity
Well Capacity (MGD) 4.38 5.82 5.26 6.98
Capacity Deficit* (MGD) 3.12 1.78 2.24 0.52
Capacity Deficit (gpm) 2,167 1,236 1,556 361
*Capacity deficit based on WTP design flow of 7.5 MGD
Based on pumping capacity, there is no scenario under which there is an adequate raw
water supply. Running the treatment plant for 24 hours per day yields a deficit of only
0.52 MGD. However, running the treatment plant and supply wells for 24-hours per day
is not good practice as it does not account for periods of maintenance or equipment
failure. However, during peak demands, it may be acceptable to run the wells for 24-
hours per day over a short period. Ten State Standards also recommends a firm capacity
equal to the maximum design demand. Using these criteria the City of Prior Lake has a
deficit of 2.24 MGD or 1,556 gpm of well water supply.
2. Treatment Capacity
The City of Prior Lake recently completed construction of a 7.5 MGD iron and
manganese filtration treatment facility, which provides adequate water treatment capacity
for the next 20 years. However, unexpected supply issues have resulted in a shortage of
water supply to the treatment plant. Currently, to meet demand requirements, the City can
purchase up to 1 MGD of water from SMSC. By purchasing water from SMSC, the City
can meet its current demands. Based on the 20 hour pumping from the wells and the
projected peak day demands, future projections indicate there will be a deficit in
treatment capacity of 0.13 MGD by 2020.
3. Storage
Currently, the City of Prior Lake has 3.25 MGD of storage capacity, which is adequate
for current flows. However, future projections indicate there will be a deficit in storage
capacity by 2035 unless more storage capacity is added.
SMSC/Prior Lake, MN – C15.110719 Page 3-5
Water System Evaluation Prepared by Bolton & Menk, Inc.
4. Summary
Table 3.5 provides a brief overview of the system evaluation for the Prior Lake Water
Treatment Plant.
Table 3.5
Prior Lake Water Treatment Plant Evaluation Overview
System Component Comments
1. Water Supply Current Well Capacity does not meet current demand.
Additional water sources are needed.
2. Water Treatment Current treatment capacity is adequate for current
demands but raw water supply is limited.
3. Water Storage Water storage facilities are adequate to meet current
demands. However, a storage deficit is predicted by 2035.
SMSC/Prior Lake, MN – C15.110719 Page 4-1
Water System Evaluation Prepared by Bolton & Menk, Inc.
SECTION 4 EVALUATION OF ALTERNATIVES
A. GENERAL
Based on the evaluation of the existing facilities, it is feasible that the needs of both the
SMSC South Service Area and the City of Prior Lake can be met through the expansion
of the SMSC South Water Treatment Plant. A partnership between SMSC and Prior Lake
on the South Treatment Plant expansion could improve water treatment capacity for the
SMSC South distribution area and future development in western Prior Lake.
Recommendations for water supply, treatment, and storage are discussed separately
below. The possibility of a future joint South Water Treatment Facility is also discussed
at the end of this section including options to use or not use City wells.
B. WATER SUPPLY
The SMSC South Service Area currently has three wells that feed the water treatment
plant. These wells provide an adequate supply of water to the distribution system during
peak demands. However, if the South Service Area WTP were to increase in capacity, a
new well would need to be added to increase the raw water supply.
The projected peak day demand is 1.55 MGD with the ICO irrigation demand included,
while the wells have the capacity to produce approximately 2.46 MGD at full capacity
while maintaining a firm capacity of 1.62 MGD. If the current South Service Area
treatment plant were to be expanded, another well would need to be added to increase the
capacity. Currently, Well No. 9 is not connected to the treatment plant and has a capacity
of 800 gpm. If this well were to be connected, the total capacity increases to 2,850 gpm
(3.42 MGD) with a firm capacity of 2,050 gpm (2.46 MGD). Adding Well No. 9 would
provide SMSC with an adequate water supply for future demands.
The City of Prior Lake currently has a well water supply deficit of 1,556 gpm. Therefore,
it is recommended to construct a new well, or several new wells that are capable of
producing at least 1,556 gpm, which would offer the City of Prior Lake the additional
water supplies during peak demands, unless a joint facility is constructed.
SMSC/Prior Lake, MN – C15.110719 Page 4-2
Water System Evaluation Prepared by Bolton & Menk, Inc.
C. WATER TREATMENT AND STORAGE
The City of Prior Lake’s water supply deficit can be mitigated by adding a raw water
supply or by adding a treated water supply directly into the distribution system. Adding a
treated water supply from the SMSC South Service Area would not only provide the
needed water supply, but would also help provide a better water quality to City of Prior
Lake. SMSC’s South Service Area WTP has the capacity for additional expansion. There
is adequate storage for peak demands and the potential to expand the facility to increase
flow by addition of a fourth well and by connecting Well No. 9.
Providing a source of treated water for the City of Prior Lake at the SMSC South Water
Treatment Plant will help to serve both community’s needs. Therefore, it is recommended
to explore option for constructing a joint facility between SMSC and Prior Lake.
D. WATER ALLOCATIONS
1. Separate Facilities
SMSC Water Treatment Plant
The new proposed water treatment facility for the South Service area would be similar to
the expansion completed in 2014 to the North Water Treatment Plant. The WTP would
have a total capacity of 2.64 MGD (2,200 gpm) and a firm capacity of 1.98 MGD (1,650
gpm). The facility would operate for 20 hours per day and consist of the following:
a. Aerator – 2,200 gpm
b. Detention Tank – 100,000 gallons
i. Detention Time: 45 minutes
c. Gravity Filters: 3 at 20’ x 18’
i. 735 gpm each
ii. Filtration rate – 2.04 gpm/ft2
d. RO-Backwash Feed/ Water System Feed Clearwells
i. RO-Backwash Clearwell – 250,000 gallons
ii. Water System Clearwell – 200,000 gallons
e. RO Units
i. 3 existing + 1 new units
ii. Space for 1 future unit
SMSC/Prior Lake, MN – C15.110719 Page 4-3
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f. RO Feed Pumps
i. 4 pumps
ii. Connection for 1 future pump
g. Backwash Pumps
i. 2 at 5,500 gpm
ii. Backwash rate – 15.3 gpm/ft2
h. High Service Pumps
i. 3 at 1,500 gpm
i. Chemical Feed
i. Antiscalant
ii. Sodium Bisulfate
iii. Sodium Hydroxide
iv. Sodium Permanganate
v. Chlorine
vi. Fluoride
vii. Corrosion Inhibitor
j. Backwash Reclaim Tanks
i. 2 Tanks at 125,000 gallons each
ii. 2 Return Pumps
iii. 2 Waste Pumps
k. Electrical including generator and controls
The new WTP would have concrete filter tanks that have an expected life of about 50
years as compared with the life expectancy of about 25 years for the steel filters in the
existing Sioux Trail WTP. SMSC would route Well No. 6, 8, 10, and connect Well No. 9
to the new treatment facility. The existing wells have sufficient capacity (both firm and
total) to meet the requirements of a new treatment facility. However, the addition of Well
No. 9 would provide for long a long term water supply. If Well No. 9 is connected to a
new facility for SMSC, no new wells would need to be drilled.
Prior Lake Water Treatment Plant
If separate facilities are to be constructed, the size of the Prior Lake WTP would need to
be the remaining difference between the projected peak 20 year demand and the current
treatment plant capacity. Currently, Prior Lake has a 7.5 MGD treatment plant. However,
raw water shortages have led to a need for a new water treatment plant. The design year
SMSC/Prior Lake, MN – C15.110719 Page 4-4
Water System Evaluation Prepared by Bolton & Menk, Inc.
will be 2036. Based on projected peak day demands and water usage, the peak day
demand will be 9.6 MGD (See Table 2.2). The difference in treatment capacity between
existing and required is 2.1 MGD. Therefore, a new treatment plant for Prior Lake would
need to have a total capacity of 2.1 MGD (1,800 gpm). The new Prior Lake water
treatment plant would operate for 20 hours per day and consist of the following:
a. Aerator – 1,800 gpm
b. Detention Tank – 85,000 gallons
i. Detention Time: 45 minutes
c. Gravity Filters: 3 at 18’ x 16’
i. 600 gpm gravity filters (each)
ii. Filtration Rate – 2.08 gpm/ft2
d. Clearwell
i. Clearwell/Backwash Feed Tank – 350,000 gallons
e. Backwash Pumps
i. 2 @ 4,500 gpm
ii. Backwash Rate – 15.6 gpm/ft2
f. High Service Pumps
i. 3 @ 1,000 gpm
g. Chemical Feed
i. Sodium Permanganate
ii. Sodium Hypochlorite
iii. Fluoride
iv. Corrosion Inhibitor
h. Backwash Reclaim Tanks
i. 2 Tanks @ 125,000 gallons each
ii. 2 Return Pumps
iii. 2 Waste Pumps
i. Electrical including a generator and controls
To accommodate a new treatment facility, Prior Lake would need to install new wells to
meet the required treatment plant capacity. Currently, the City has Well No. 6 that is used
to supplement water into the system during peak demands when there is a water shortage.
This water is untreated when it enters the system. Therefore, Well No. 6 would be
SMSC/Prior Lake, MN – C15.110719 Page 4-5
Water System Evaluation Prepared by Bolton & Menk, Inc.
connected to a new water treatment plant in Prior Lake. The total capacity of Well No. 6
is 1,200 gpm (1.73 MGD) when operating for 24 hours per day. To match water
treatment plant operations, the well would operate for 20 hours per day yielding a
capacity of 1.44 MGD. Firm capacity is the capacity with the largest well out of service.
To meet firm capacity requirements, Prior Lake would need to drill two additional wells
capable of producing at least 900 gpm each.
2. Joint Facility – City Wells
The City of Prior Lake has indicated during past discussions that they may be interested
in being part of a joint water treatment facility. Prior Lake has a 16-inch watermain at
County Road 82 and Mystic Lake Boulevard. The proposed WTP location would allow
for a convenient connection to their water system. However, efficiencies, which are
expected with the larger capacity joint WTP would result in SMSC’s share of the WTP to
be less than the cost estimated for a SMSC only WTP. Sale of water to Prior Lake could
also generate revenue for SMSC. A joint water treatment facility may prove to be a
feasible option to provide a safe and stable source of drinking water to both SMSC and
Prior Lake. A joint water treatment facility would operate for 20 hours per day to allow
time for backwash and maintenance and it would consist of the following:
a. Aerators 2 – 2,000 gpm each
b. Detention Tank – 180,000 gallons
i. Detention Time: 45 minutes
c. Gravity Filters: 6 at 20’ x 16’
i. 667 gpm gravity filters (each)
ii. Filtration Rate – 2.08 gpm/ ft2
d. RO-Backwash Feed/ Water Systems Feed Clearwells
i. RO-Backwash Clearwell – 250,000 gallons
ii. SMSC Clearwell – 200,000 gallons
iii. Prior Lake Clearwell – 200,000 gallons
e. Prior Lake HSP
i. 3 @ 1,000 gpm
SMSC/Prior Lake, MN – C15.110719 Page 4-6
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f. RO Units
i. 3 existing + 1 new units
ii. Space for 1 future unit
g. RO Feed Pumps
i. 4 pumps
ii. Connection for 1 future pump
h. Backwash Pumps
i. 2 @ 5,500 gpm
ii. Backwash Rate – 17.2 gpm/ ft2
i. High Service Pumps
i. 3 @ 1,500 gpm
j. Chemical Feed
i. Antiscalant
ii. Sodium Bisulfate
iii. Sodium Hydroxide
iv. Sodium Permanganate
v. Chlorine
vi. Fluoride
vii. Corrosion Inhibitor
k. Backwash Reclaim Tanks
i. 3 Tanks @ 125,000 gallons each
ii. 3 Return Pumps
iii. 3 Waste Pumps
j. Electrical including a generator and controls
The proposed joint facility would need to be sized to accommodate the peak demand for
both Prior Lake and SMSC. Earlier discussion indicated that a new plant for SMSC
would be sized to handle a total capacity of 2.64 MGD. The existing WTP for SMSC
contains three RO units. A new joint facility would be designed with space to add a
fourth RO unit to increase capacity. The size of the Prior Lake Facility would be designed
at 2.1 MGD, based on 20 year future water usage and peak day demands.
To achieve the required capacity, wells from both the City and SMSC would be used.
Combining the two plant sizes together yields a total required treatment plant capacity of
4.74 MGD. To address the capacity of a joint facility, both the City and SMSC will
provide raw water. The goal is to have Prior Lake feed the water they would use to meet
SMSC/Prior Lake, MN – C15.110719 Page 4-7
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peak day demands. To accomplish this, Prior Lake would need to drill new wells. The
existing wells would continue to feed the existing treatment plant. For a new treatment
plant, the firm capacity of the wells would need to be 1,800 gpm. Well No. 6 is capable
of producing 1,200 gpm. To meet firm capacity, additional wells would need to be drilled
and be capable of producing at least 900 gpm each, bringing the total raw water supply to
3,000 gpm.
SMSC would route Wells 6, 8, 10 to a joint facility and Well No. 9 would be connected
to the plant. The addition of all the wells from SMSC would yield a total capacity of
2,850 gpm (3.42 MGD), with a firm capacity of 2,050 gpm (2.46 MGD) based on 20
hours of run time per day (from SMSC). Combining both SMSC and Prior Lake wells
and projected wells to be drilled, the total capacity of the raw water supply is 5,850 gpm,
(7.02 MGD) of raw water supply, with a firm capacity of 4,650 gpm (5.58 MGD). This
greatly exceeds the required demand for a joint facility and provides a long-term solution
for both SMSC and Prior Lake. Table 4.1 breaks down the existing well capacities and
what is required to feed a joint facility.
In order to provide an adequate water supply to each community, Prior Lake will have to
install two wells capable of producing 900 gpm each and SMSC will have to connect
Well No. 9.
SMSC/Prior Lake, MN – C15.110719 Page 4-8
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Table 4.1
Projected Raw Water Supply with New Wells
Prior Lake Wells
Well No. Capacity (gpm) Capacity
(MGD) (3)
Existing Well No. 6 (Wilds Well) 1,200 1.44
New Well(1) 900 1.08
New Well(1) 900 1.08
SMSC Wells
Well No. Capacity (gpm) Capacity
(MGD) (3)
Existing Well No. 6 700 0.84
Existing Well No. 8 650 0.78
Well No. 9(1) 800 0.84
Existing Well No. 10 700 0.96
Total
Total Capacity SMSC + Prior Lake 5,850 7.02
Firm Capacity SMSC + Prior
Lake(2) 4,650 5.58
(1) New wells to be drilled or connected to a Joint Facility
(2) Capacity without largest well (Prior Lake Well No. 6)
(3) Capacity (MGD) based on 20 hour per day operation
3. Joint Facility – No City Well
As stated earlier, a joint facility would need to be design with a capacity of 4.74 MGD to
accommodate current and future flows for the next 20 years for both the SMSC South
Service Area and the City of Prior Lake. The components and sizes for a joint facility are
described above. A joint WTP would utilize the three existing wells for SMSC located
near the current Sioux Trail WTP and Well No. 9. All of these wells would be provided
by SMSC. A joint facility would have a total required capacity of 4.74 MGD. The SMSC
wells have the capacity to meet the demands for SMSC, but additional wells would need
to be drilled to meet the demand for Prior Lake. The projected Prior Lake demand is 2.1
MGD. To reduce the demand from Prior Lake, Well No. 6 would be connected to the
facility, but no other Prior Lake Wells would be connected. Well No. 6 has a total
capacity of 1,200 gpm.
The additional four wells from SMSC can produce 2,850 gpm total. To make up the
difference between the required treatment plant capacity of 3,950 gpm (4.74 MGD) and
SMSC/Prior Lake, MN – C15.110719 Page 4-9
Water System Evaluation Prepared by Bolton & Menk, Inc.
the current raw water supply provided of 2,850 gpm, SMSC would need to drill another
well capable of producing at least 1,100 gpm. This will meet firm capacity requirements
for the facility. The breakdown of well capacity is shown in Table 4.2.
The requirements for a joint facility indicate that Prior Lake will not drill any new wells
but they will need to connect Well No. 6 and SMSC will need to connect Well No. 9 and
drill one more well capable of producing at least 1,100 gpm.
Table 4.2
Projected Raw Water Supply with New SMSC Wells
Prior Lake Wells
Well No. Capacity (gpm) Capacity
(MGD) (5)
Well No. 6 1200 1.44
SMSC Wells
Well No. Capacity (gpm) Capacity
(MGD) (5)
Well No. 6 700 0.84
Well No. 8 650 0.78
Well No. 9(1) 700 0.84
Well No. 10 800 0.96
New Well(2) 1100 1.32
Total
Total Capacity 5150 6.18
Firm Capacity (4) 3950 4.74 (3)
(1) Connect existing well to joint facility
(2) New well(s) to be drilled
(3) Meets joint facility minimum capacity
(4) Capacity with largest well out of service (Prior Lake Well No. 6)
(5) Capacity (MGD) based on 20 hour per day operation
SMSC/Prior Lake, MN – C15.110719 Page 5-1
Water System Evaluation Prepared by Bolton & Menk, Inc.
SECTION 5 COST ESTIMATE & PROPOSED IMPLEMENTATION
A. GENERAL
This section explains the costs of the proposed alternatives described in section 4. The
section also discusses project financing and proposed implementation of the alternatives.
B. COST ESTIMATE
Estimated construction costs for a SMSC only Water Treatment Plant, Prior Lake only
Water Treatment Plant, and SMSC-Prior Lake Joint Water Treatment Plant are presented
in Table 5.1. The construction of two separate facilities results in a total estimated
construction cost of $29,058,500 compared to an estimated construction cost of
$19,472,250 for the joint water treatment facility.
Table 5.1
Estimated Construction Costs
Water Treatment Facility
June 2016
ITEM
NO.
ITEM DESCRIPTION ESTIMATED COST
SMSC Prior Lake Joint Facility
1 Performance Bond & Insurance $250,000 $250,000 $425,000
2 Mobilization $420,000 $420,000 $550,000
3 Excavation, Utilities, Roads, Landscaping $2,180,000 $1,450,000 $2,650,000
4 Reinforcing Steel, Concrete Work, Precast $2,150,000 $1,950,000 $2,750,000
5 Masonry $950,000 $950,000 $1,250,000
6 Structural & Miscellaneous Metals $250,000 $250,000 $325,000
7 Rough & Finished Carpentry $75,000 $75,000 $85,000
8 EPDM Roofing, Insulation, Caulking $145,000 $145,000 $245,000
9 H.M. Doors, Overhead Doors $110,000 $110,000 $140,000
10 Painting and Interior Finishes $250,000 $250,000 $325,000
11 Process Equipment $2,275,000 $1,750,000 $3,150,000
12 Process Piping & Mechanical $2,320,000 $2,100,000 $2,950,000
13 Electrical, Controls & Generator $2,150,000 $1,950,000 $2,700,000
14 2 – Additional Wells $0 $1,500,000 $0
15 Raw Water Lines $0 $1,000,000 $1,000,000
Subtotal $13,525,000 $14,150,000 $18,545,000
Contingency – 5% $675,000 $707,500 $927,250
ESTIMATED CONSTRUCTION COST $14,200,000 $14,857,500 $19,472,250
Table 5.2 provides the joint facility construction cost breakout that should be associated
with SMSC and the City of Prior Lake.
SMSC/Prior Lake, MN – C15.110719 Page 5-2
Water System Evaluation Prepared by Bolton & Menk, Inc.
Table 5.2
Estimated Construction Costs Breakout
Joint Water Treatment Facility
June 2016
ESTIMATED COST BREAKOUT
ITEM NO.ITEM DESCRIPTION Joint Facility SMSC Prior Lake
1 Performance Bond & Insurance $425,000 $233,750 $191,250
2 Mobilization $550,000 $302,500 $247,500
3 Excavation, Utilities, Roads, Landscaping $2,650,000 $1,457,500 $1,192,500
4 Reinforcing Steel, Concrete Work, Precast $2,750,000 $1,650,000 $1,100,000
5 Masonry $1,250,000 $750,000 $500,000
6 Structural & Miscellaneous Metals $325,000 $178,750 $146,250
7 Rough & Finished Carpentry $85,000 $46,750 $38,250
8 EPDM Roofing, Insulation, Caulking $245,000 $134,750 $110,250
9 H.M. Doors, Overhead Doors $140,000 $77,000 $63,000
10 Painting and Interior Finishes $325,000 $178,750 $146,250
11 Process Equipment $3,150,000 $1,890,000 $1,260,000
12 Process Piping & Mechanical $2,950,000 $1,770,000 $1,180,000
13 Electrical, Controls & Generator $2,700,000 $1,620,000 $1,080,000
14 2 – Additional Wells $0 $0 $0
15 Raw Water Lines $1,000,000 $0 $1,000,000
Subtotal $18,545,000 $10,289,750 $8,255,250
Contingency – 5%$927,250 $514,488 $412,763
ESTIMATED CONSTRUCTION COST $19,472,250 $10,804,238 $8,668,013
As shown in Table 5.2, there is a significant savings for both SMSC and the City of Prior
Lake by constructing a joint water treatment facility that will serve both community’s
needs as opposed to constructing separate facilities.
C. PROJECT FINANCING
The City of Prior Lake’s portion of the project will be funded by the sale of a bond to
SMSC. The City of Prior Lake will pay for the Bond to SMSC at a rate of 3% over a 25-
year period. Based on the Construction Cost Estimate for the Joint Facility as presented
in Table 5.1, and the City’s share of that cost as determined in Table 5.2 and the purchase
of 1,200,000 gallons per day equates to a yearly payment of $497,760 or $1.14/ 1,000
gallons used. The actual payment would vary depending on actual construction costs.
In addition to the yearly bond costs, the City of Prior Lake would also pay operation and
maintenance costs for their portion of the treated water, along with yearly payments to
SMSC/Prior Lake, MN – C15.110719 Page 5-3
Water System Evaluation Prepared by Bolton & Menk, Inc.
fund equipment replacement in the future. The yearly maintenance cost to be paid to
SMSC by the City of Prior Lake would be $15,000 to cover materials and labor
associated with and equipment maintenance or repairs. SMSC would also receive
reimbursement from the City of Prior Lake for seven (7) hours/week of operator fees.
This would result in a yearly payment of $28,400. Equipment replacement funds are
presented in Table 5.3, and would result in a yearly payment of $35,000 to SMSC from
Prior Lake. The total yearly payment to SMSC from the City of Prior Lake for
operations, maintenance and future equipment replacements (OM&R) would be $78,400
or $0.10/1,000 gallons of water used. The City of Prior Lake would also pay the
electrical costs associated with power for equipment operations and chemical costs
associated with the volume of water pumped to their distribution system.
Table 5.3
Equipment Replacement Funds
Joint Water Treatment Facility
June 2016
Replacement
Schedule
Replacement
Cost
Yearly Contribution
to Replacement Fund
Prior Lake Portion of
Replacement Fund
Equipment
Replacement 15 Years $500,000 $33,000 $22,000
Filter
Rehabilitation 20 Years $360,000 $18,000 $9,000
Well Pulling/
Maintenance 5 Years $75,000 $15,000 $4,000
Total $935,000 $66,000 $35,000
Based on the City of Prior Lake receiving a minimum of 1,200,000 gallons per day (438
million gallons per year) of treated water from the new joint WTP, the annual anticipated
payment from the City of Prior Lake is $810,300. The breakout of operating expenses
and bond payments are shown in Table 5.4. Should the City use more than the 438
million gallons annually, the additional charge for treated water would only include the
cost of power and chemicals.
SMSC/Prior Lake, MN – C15.110719 Page 5-4
Water System Evaluation Prepared by Bolton & Menk, Inc.
Table 5.4
Operating Expenses and Bond Payments
Expense Item Cost per 1,000 Gallons
OM&R Costs $0.18
Electrical Costs $0.25
Chemical Costs $0.28
Bond Payment Costs $1.14
Total Costs $1.85
D. IMPLEMENTATION SCHEDULE
A proposed implementation schedule for the joint water treatment plant is presented in
Table 5.5.
Table 5.5
Implementation Schedule
Joint Water Treatment Facility
ITEM DATE
1. Presentation to Both Councils June 2016
2. Approve Study and Cost Sharing Agreement September 2016
3. Prepare Plans and Specifications October – December 2016
4. Review and Approval of Contract Documents January – February 2017
5. Project Construction April 2017 – November 2018
SMSC/Prior Lake, MN – C15.110719 Page 6-1
Water System Evaluation Prepared by Bolton & Menk, Inc.
SECTION 6 ADDITIONAL CONSIDERATIONS
A. GENERAL
This section discusses additional considerations for water supply and water conservation.
The content discussed in this section provides information on how to conserve water
through various methods and addresses alternate sources of water for drinking and
irrigation.
B. REGIONAL WATER SUPPLY PLANNING
C. WATER CONSERVATION
1. Irrigation Practices
Irrigation is a common practice by many homeowners to keep lawns green during
the summer months. During wet summers, homeowners do not need to irrigate as
often because of the increased natural rainfall. During dry summers however,
irrigation spikes as homeowners try to keep lawns green. These dry summers can
stress water supply sources and potentially cause a shortage of water in the
distribution system.
One option to reduce the effect of irrigation on the water supply is to regulate
when irrigation can occur. Irrigating on odd days reduces the volume of water
used for irrigation while maintaining green lawns. Also, irrigating at night reduces
the amount of water lost to evaporation. As the communities of SMSC and Prior
Lake continue to grow, it is important to consider several different practices
concerning irrigation to help mitigate the effect irrigation has on the water supply
system.
2. Educational Efforts
Educational play a major role in water conservation and how certain practices can
be implemented in homes and communities. These practices range from installing
efficient fixtures in homes to less irrigating to buying water efficient appliances.
Several agencies have articles that describe these practices. They include:
SMSC/Prior Lake, MN – C15.110719 Page 6-2
Water System Evaluation Prepared by Bolton & Menk, Inc.
Minnesota Rural Water Association
US Environmental Protection Agency
Alliance for Water Efficiency
Metropolitan Council
American Water Works Association
D. ADDITIONAL WATER SOURCES
1. Storm Water for Irrigation
Another source of water for irrigation is storm water. During storm events, water
can be collected and then stored for later use by irrigation. Storm water retention
ponds can be added with control structures that allow water to remain in the ponds
until needed for irrigation. One drawback to this system is that it has to rain in
order for water to fill the ponds. During dry years, ponds may never fill and
irrigation cannot occur. During wet years, the ponds may overflow because
nobody needs irrigation water because of the increased natural rain fall.
4646 Dakota Street SE
Prior Lake, MN 55372
RESOLUTION 16-090
A RESOLUTION SUPPORTING DESIGN OF A JOINT WATER TREATMENT PLANT WITH
THE SHAKOPEE MDEWAKANTON SIOUX COMMUNITY
Motion By: McGuire Second By: Keeney
WHEREAS, The Shakopee Mdewakanton Sioux Community (SMSC) and the City of Prior Lake
both have water source, treatment and storage needs which should be operational
by 2019; and
WHEREAS, The SMSC will be starting the design process for a new treatment plant in 2016 ;
and
WHEREAS, The SMSC and the City of Prior Lake conducted a collaborative study to evaluate
the future water needs of both communities and potential options for supplying
those needs; and
WHEREAS, The study showed that there is a cost benefit to both communities to construct a
joint water treatment facility including storage and source options to supply these
needs; and
WHEREAS, The study looked at two options for supply of the source water that included SMSC
owned and operated wells and City of Prior Lake owned and operated wells.
NOW THEREFORE, BE IT HEREBY RESOLVED BY THE CITY COUNCIL OF PRIOR LAKE,
MINNESOTA as follows:
1. The recitals set forth above are incorporated herein.
2. The City Council supports the SMSC designing the Water Treatment Plant to incorporate the
future water treatment needs of the City of Prior Lake.
3. The City Council supports making use of existing source water wells with future City supply
wells being owned by the City.
4. The City Council directs staff to develop a draft water supply agreement with the SMSC.
PASSED AND ADOPTED THIS 11th DAY OF JULY 2016.
VOTE Hedberg Keeney McGuire Morton Thompson
Aye
Nay
Abstain
Absent
Frank Boyles, City Manager
Water Planning &
Joint Water Facility
City Council Work Session
June 27, 2016
Purpose
•Review City water supply needs
•Review options to meet needs
•Current CIP includes new WTP in 2019
•Possible Partnership with SMSC
•SMSC starting design process for new WTP
•Need Council direction to inform CIP
preparation
Prior Lake Existing Water System
Water Treatment Plant (WTP) –7.5 MGD
Seven (7) wells
6 wells pump to WTP
1 well not connected (Well 6 –Wilds well)
Used during peak times, not treated (has Fe and Mn)
Firm pumping capacity is pumping rate with largest well out
of service
Firm pumping capacity is 5.26 MGD (24 hour pumping)
Storage
3.25 MG of storage (elevated and ground storage)
Prior Lake Existing Water System
Prior Lake has an agreement with SMSC for water supply
Original agreement for 1 MGD
SMSC constructed a 3rd well in 2015
Revised agreement for 1.2 MGD
Additional well increases Prior Lake’s firm capacity
Allows postponement of Well 10 in CIP
2012 Water Issues
Summer of 2012 high water demand
Hot weather and little to no rain
Towers (storage) balance the system
Draw from towers during day (peak usage period)
Fill towers during night (lower usage period)
Risk of Water Ban
Ran all wells during high demand
Not meeting demands
Could not keep towers full
At Risk for water shortage if we lose a well
Added pressure on aquifer (extended pumping)
Planning for Water Infrastructure
Significant planning and preparation required for water
infrastructure (WTP, wells and storage)
Permitting (MDH, DNR, water appropriations, etc.)
Design
Construction
Coordination of wells with SMSC
Possible interference (close proximity of wells)
Geology of the area -challenging
Planning for Water Infrastructure
2020 Projected Peak Day Demand 6.95 MGD
Additional Source, Treatment and storage will be needed
at this time
CIP programs $16.0 million for:
Two additional wells
WTP
Storage
What are the options?
Prior Lake builds WTP, wells and storage
Seek a Partnership
SMSC -Expand current agreement (1.2MGD)
Savage
Currently have 2 interconnects
Different water quality
Cost of Water
Option 1 –Prior Lake Build
Construct new WTP
Use well 6 –pipe to new WTP
Drill new wells (at least 2 to provide firm capacity)
Storage requirements
Elevated
Ground (part of WTP)
Option 2 –Partnership w/SMSC
Size new WTP for both SMSC and Prior Lake
Fe and Mn removal for both Prior Lake and SMSC
Reverse osmosis for SMSC
Use existing wells
Prior Lake Well #6
SMSC –3 existing wells
Meet firm pumping capacity requirements
Storage requirements
Elevated
Ground (part of WTP)
Option 1
Separate Facilities
Option 2
Joint Facility
PROS
•City Owns and operates all
improvements. No risk of agreement
sunset or termination.
PROS
•Both entities can take advantage of
shared redundancies (i.e. wells to meet
firm pumping capacity) equating to
less cost
•Pay as you go
CONS
•Possible interference of wells and
aquifer drawdown
•Up front Capital Cost
CONS
•Risk of agreement sunset or
termination
Benefit of Partnership
Prior Lake Only SMSC Only
Joint Prior Lake/SMSC
4.80 MGD
Backwash Pumps
Chemical Feed
Reclaim Tanks
4 Wells
Storage
Prior Lake
HSPs
SMSC
RO
HSPs
2.20 MGD
3 -Filters
3 -HSPs
3 Wells
Storage
2.64 MGD
3 –Filters
RO
3 -HSPs
3 Wells
Storage
Estimated Costs
Estimated Construction Costs
Water Treatment Facility
June 2016
ITEM
NO.
ITEM DESCRIPTION ESTIMATED COST
SMSC Prior Lake Joint Facility
1 Performance Bond & Insurance $250,000 $250,000 $425,000
2 Mobilization $420,000 $420,000 $550,000
3 Excavation, Utilities, Roads, Landscaping $2,180,000 $1,450,000 $2,650,000
4 Reinforcing Steel, Concrete Work, Precast $2,150,000 $1,950,000 $2,750,000
5 Masonry $950,000 $950,000 $1,250,000
6 Structural & Miscellaneous Metals $250,000 $250,000 $325,000
7 Rough & Finished Carpentry $75,000 $75,000 $85,000
8 EPDM Roofing, Insulation, Caulking $145,000 $145,000 $245,000
9 H.M. Doors, Overhead Doors $110,000 $110,000 $140,000
10 Painting and Interior Finishes $250,000 $250,000 $325,000
11 Process Equipment $2,275,000 $1,750,000 $3,150,000
12 Process Piping & Mechanical $2,320,000 $2,100,000 $2,950,000
13 Electrical, Controls & Generator $2,150,000 $1,950,000 $2,700,000
14 2 –Additional Wells $0 $1,500,000 $0
15 Raw Water Lines $0 $1,000,000 $1,000,000
Subtotal $13,525,000 $14,150,000 $18,545,000
Contingency –5%$675,000 $707,500 $927,250
ESTIMATED CONSTRUCTION COST $14,200,000 $14,857,500 $19,472,250
Estimated Costs
Construction Cost Comparison
Estimated
Construction
Cost
Community’s
Share of Joint
Facility
Total Savings
with Joint
Facility
SMSC $14,200,000 $10,804,238 $3,395,762
Prior Lake $14,857,500 $8,668,013*$6,189,487
Joint $19,472,250
*Current Agreement includes capital in volume wholesale rate ($/1,000 gallons
purchased). No up front capital was required.
Partnership with SMSC
Expand Existing agreement
SMSC owns all of the infrastructure
Costs per 1,000 gallons based on:
Day to day operational and maintenance costs
Replacement costs
Capital costs
Pay as you go option (no financing by City)
Partnership with SMSC
Another option for partnership
Prior Lake owns source water (skin in the game)
Prior Lake only pays for treatment of water
Prior Lake responsible for building wells and raw
watermains to SMSC WTP
Prior Lake responsible for operation and maintenance
of wells
Potential sale of raw water to SMSC
Partnership with SMSC
Is there a benefit to having SMSC provide all of the wells?
Is it potentially easier for SMSC to permit and obtain
wells?
SMSC still permits for wells
EPA consults with local agencies (DNR, MDH)
No regulatory benefit
Questions & Next Steps
SMSC Business Council Supports a joint WTP
Is the Council interested in a continued water partnership
with the SMSC?
SMSC provides both source water and treatment?
Prior Lake own wells & pays only for water treatment?
Staff will bring a resolution to the next meeting indicating
Prior Lake’s support for a joint WTP
Staff will work with the SMSC to draft a joint agreement