HomeMy WebLinkAbout2040 Chapter 07 - Surface Water
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 146
CHAPTER 7, SURFACE WATER MANAGEMENT
7.1 EXECUTIVE SUMMARY
A. Local Surface Water Management Plan Purposes This report provides the City of Prior Lake with a Local Surface Water Management
Plan (LSWMP) that will serve as a policy basis for the management of the surface water system throughout the City. The LSWMP is incorporated as part of the City’s
2040 Comprehensive Plan. The LSWMP will carry the City through the end of 2027.
Amendments to the Plan will occur in the intervening 10 years so that the Plan remains current to watershed plan updates and rule revisions and current to the
“state of the art” in surface water management.
The Prior Lake LSWMP will serve as a comprehensive planning document. Through
implementation of the LSWMP, the City will demonstrate its commitment to conserving, protecting, and managing its surface water resources. The LSWMP meets requirements as established in Minnesota Rules 8410 and Minnesota Statute
103B.235. In addition, the participation of other organizations, particularly Scott WMO (SWMO) and Prior Lake-Spring Lake Watershed District (PLSLWD), ensures the
City’s compliance with local and regional expectations.
B. Executive Summary
The Prior Lake LSWMP is organized as follows:
• Section 7.1 Executive Summary provides background information and summarizes the plan contents.
• Section 7.2 Land and Water Resource Inventory describes the physical environment including watersheds and drainage patterns, dominant land uses, and significant water bodies within the City.
• Section 7.3 Wetland Management Plan provides an overview of regulating requirements, procedures, and wetland protection/enhancement goals.
• Section 7.4 Agency Cooperation outlines other governmental controls and programs that affect stormwater management.
• Section 7.5 Assessment of Problems and Issues presents the City's water management related problems and issues.
• Section 7.6 Goals and Policies outlines the City's goals and policies pertaining to water management.
• Section 7.7 Implementation Program presents the implementation program for the City of Prior Lake, which includes defining responsibilities, prioritizing, and
listing the program elements.
• Section 7.8 Administration outlines the continued administration of this plan
with respect to plan updates and amendments.
• Appendices are included in the back of the plan. These documents are
included because they provide supporting information to the main body of the
plan, are useful information, and/or are required to be included in this plan
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update. Direct website links to relevant reports or documents are provided
throughout the report as appropriate.
o Appendix A – Figures o Appendix B – MS4 Documents o Appendix C – Relevant City Ordinances
o Appendix D – Prior Lake-Spring Lake Watershed Rules o Appendix E – Scott WMO Standards o Appendix F – Public Works Design Manual (PWDM)
o Appendix G – Wellhead Protection Plan o Appendix H – Street Sweeping and Winter Maintenance Policies
o Appendix I – Water Resources Related Agreements
o Appendix J – Wetland Bank Study
C. Summary of Recommendations The following recommendations are presented for the City Council's consideration
based upon the data compiled in this report: 1. The City of Prior Lake should adopt the Local Surface Water Management Plan
as presented.
2. Establish standard review procedures to ensure all new development or
redevelopment within the City is in compliance with the grading and stormwater management controls determined by this Plan.
3. Require detailed hydrologic analyses for all development and redevelopment activities.
4. Establish final high-water levels governing building elevations adjacent to ponding areas and floodplains as development occurs or when drainage facilities
are constructed.
5. Establish and maintain overflow routes to provide relief during extreme storm
conditions, which exceed design conditions. 6. Perform stormwater system maintenance to ensure the successful operation of
the system.
7. Enforce the erosion and sediment control criteria for new developments.
8. Implement an education program for City residents, staff, and development
community.
9. Adopt and implement amendments to the plan as warranted by future standards
or regulations.
10. Amend the plan as required throughout the 10-year implementation period.
11. Promote the use of regional/consolidated BMPs to help achieve water quality
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and volume control goals.
12. Pursue partnerships with watershed districts and other organizations to incorporate BMPs into redevelopment projects, including City projects.
13. Revise ordinances to be consistent with rules detailed in the Public Works
Design Manual (PWDM) regarding stormwater management.
14. Require compliance with state wetland rules through local implementation of the
Wetland Conservation Act (WCA).
7.2 LAND AND WATER RESOURCE INVENTORY A. Location and History
The City of Prior Lake is located in north central Scott County at the nexus of major
transportation corridors including Trunk Highway 13, Scott County Road 21 and Scott
County Road 42. Appendix A – Figure 7.1 shows the City’s location within the Twin Cities metro.
The City’s population has increased from just 848 in 1960 to over 25,000 today, with the greatest growth occurring in the last 20 years. Table 7.1 provides City populations
and population projections from 1960 through 2040. As the City continues to grow, the
importance of adequate surface water management controls also grows. The LSWMP details these controls and makes the connection between these controls and the
overall city goal of preserving and enhancing its natural resources and protecting its
residents from flooding.
Table 7.1 Population and Households Year Population Number of Households
1960 848 -
1970 4,127 -
1980 7,284 -
1990 11.482 -
2000 15,917 5,645
2010 22,796 8,447
2016 25,520 9,291
2020 27,500 10,500
2030 32,500 12,600
2040 37,600 14,700
Source: Metropolitan Council Annual Estimates and Population Forecasts
Lakes define the City since the core of the community developed between Upper and
Lower Prior Lake. The City’s uniqueness is tied to the lakes. Consequently, effective
surface water management cuts to the core of the City’s vision for the future.
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B. Physical Setting
1. Topography and Geology
The topography and geology of Prior Lake was influenced by several ice sheets that advanced and retreated across southern Minnesota during the glacier age. The
most recent glacier deposited light yellowish-brown or light olive-brown, calcareous,
moderately fine textured material. The glacial action of the area resulted in the current irregular topography, called an ice-stagnation and disintegration moraine.
Some areas contain deep unconsolidated surficial material, up to several hundred
feet deep.
The City of Prior Lake is located on the upland area of the south side of the
Minnesota River, in Scott County. The area has considerable relief, with steep slopes and potholes common throughout the region. Many of the potholes are low
wetland areas. Appendix A - Figure 7.2 shows the changing topography within the
City.
2. Drainage Systems
The City of Prior Lake and the Prior Lake hydrologic system are part of the larger
Minnesota River watershed. The City of Prior Lake is approximately 4 miles south of the Minnesota River and drainage within the Prior Lake system is to the north
and northeast. The City’s Prior Lake system connects directly to the River through
the operation of the Prior Lake outlet, which is owned and maintained by the PLSLWD. A portion of the City, northwest of Spring Lake and within the Scott
WMO jurisdiction, drains northeast into Shakopee. Appendix A - Figure 7.3 shows
the drainage areas of the City.
Prior to 1983, Prior Lake was a land-locked lake which had a natural outlet
approximately 18 feet above what was considered normal water level. In 1981 plans were prepared for constructing a 36” RCP outlet pipe from Prior Lake with
an outlet on the west side of County Road 21 into what is known as “Jeffers Pond.” This project also included upgrading the existing ditch and culvert system to drain the water all the way to the Minnesota River. The water level to which
Prior Lake is allowed to be drained is 902.5, 18” below the Ordinary High-Water Level (OHWL) of 903.9 as established by the Department of Natural Resources (DNR). According to DNR lake level records dating back to 1940, the lake level
has varied from 893.48 to 906.17, with a long-term average of 902.02.
Most of the City’s drainage – both current and within the 2040 growth area – ends
up in either Prior Lake or in the Prior Lake outlet channel. Because of this, most of the land area within the City falls within the jurisdiction of the PLSLWD. A portion
of the City and City 2040 growth area falls within the Scott WMO; this area lies
northwest of Spring Lake and generally drains toward Louisville Swamp, which lies approximately 2 miles west of the 2040 growth area boundary.
The PLSLWD encompasses approximately 42 square miles of land in the jurisdictions of six local units of government: Prior Lake, Savage, Shakopee, Sand
Creek Township, Spring Lake Township, and the Shakopee Mdewakanton Sioux
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Community (SMSC). Primary water resources within both the PLSLWD and the
City, which are discussed in detail below, include Spring Lake, Upper and Lower Prior Lakes, Rice Lake, and Crystal Lake. Jeffers Pond and Pike Lake are notable water resources that form a portion of the Prior Lake outlet channel.
Historically, three other watershed management organizations operated near the
City of Prior Lake. These were the Sand Creek, Credit River, and Shakopee Basin
WMOs. All three WMOs were determined to be “non-implementing” and were subsequently disbanded by the state Board of Water and Soil Resources. Scott
County then assumed the powers of these organizations through creation of the
Scott WMO. The Scott WMO includes all of Scott County not currently managed by the PLSLWD, the Lower Minnesota River Watershed District, the Vermillion
WMO or the Black Dog WMO.
The primary Scott WMO hydrologic features within Prior Lake's existing or 2040
boundary include Mystic, Campbell, Markley, and Howard Lakes.
3. Soils
Soils of the Prior Lake area are classified into three associations:
• Lester, Webster, Glencoe Association
• Hayden and Lester soils and Peat bogs Association, and
• Burnsville, Hayden, Kingsley, Scandia Association.
Information about each of the soil series listed above is available from the Scott
County Soil Survey. Table 7.2 shows the drainage characteristic of each soil series from the above associations.
Table 7.2 Soil Drainage Characteristics Soil Series Draining Characteristic Soil Type
Burnsville, Hayden, Kingsley
and Scandia
well drained to excessively drained B
Glencoe very poorly drained D
Hayden well drained B
Lester well drained B
Peat Bogs poorly drained D
Webster poorly drained D
Note: Because the Burnsville, Hayden, Kingsley and Scandia series has formed from a mixing of two different kinds of glacial drift, it is impractical to separate each into a
separate series.
The drainage nature of the soil is important for determining the surface water runoff from a given area. If the soil is well-drained, a significant portion of the
precipitation will be infiltrated into the ground, whereas if a soil is very poorly drained, most of the precipitation will flow from the site of impact.
The hydrologic soil group (HSG) defines a soils propensity to generate runoff for a given rainfall event. Four HSG groups area identified: A, B, C, D. HSG A soils
have the lowest potential to generate runoff and are typically sandy or gravelly
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soils. HSG D soils have the highest potential to generate runoff and typically
consist of muck, peaty muck, and tight clay soils. The associations found within the Prior Lake LSWMP study area fall into HSG B to D, indicating a moderate to high potential to generate runoff. Soil types are showing in Appendix A - Figure
7.4.
Hydric soils are those characteristic soils found in wetland areas. A wetland must
possess three technical criteria in order for it to be identified as a wetland. These three are: 1) hydrophytic vegetation, 2) hydric soils, and 3) wetland hydrology. The
definition of a hydric soil is: “a soil that is saturated, flooded, or ponded long
enough during the growing season to develop anaerobic conditions in the upper part”. A map of hydric soils found in Scott County is shown in Appendix A - Figure
7.5.
4. Climate and Precipitation
The climate within the Twin Cities Metropolitan Area is typical of a humid continental climate with moderate precipitation and wide daily temperature
variations. Without the buffering influence of large bodies of water, cold winters and hot summers predominate. It is generally understood that global climate change has an effect on the Metropolitan Area’s local climate. One area where
climate change manifests itself is in rainfall intensities and rainfall depths. The Metropolitan Area has seen more intense rainfalls the last two decades and even
the average rainfalls seem more intense. Because of this change in precipitation,
flood control facilities, if designed for the 100-year rainfall, may get larger as the statistical 100-year rainfall gets larger. Also, facilities designed for smaller events,
such as infiltration areas and small storm sewer may also get larger as rainfall
depths increase for the 1-year to 5-year rainfall events.
The total average annual precipitation in the Metropolitan Area is approximately
30.6 inches. The total average annual snowfall is approximately 54.4 inches. Additional climatological information for the area can be obtained from the
Minnesota State Climatology Office at: http://www.dnr.state.mn.us/climate/twin_cities/index.html.
Rainfall frequency estimates are used as design tools in water resource projects.
Rainfall frequencies are summarized in Technical Paper No. 40, Rainfall Frequency Atlas of the United States, published by the U.S. Weather Bureau in
1961. This document was updated in 2013. Atlas 14 is the current document used as reference for rainfall frequencies. It has
been adopted by the PLSLWD and the City in their respective stormwater management rules. Table 7.3 lists Atlas 14 rainfall frequencies for Prior Lake.
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Table 7.3 Atlas 14 Rainfall Depths and Frequency
Recurrence Interval
(yrs)
24-hr Rainfall Depth
(in) 1 2.49
2 2.84
5 3.54
10 4.22
50 6.30
100 7.39
Additional precipitation information for the area can be obtained from the
National Oceanic and Atmospheric Administration (NOAA) website at http://hdsc.nws.noaa.gov/.
5. Land Use
Appendix A - Figure 7.6 provides the existing land use for the City of Prior Lake.
City growth will be concentrated in the areas around Spring Lake and to the west
of Spring Lake. Obviously, growth requires planning for other utilities and transportation in addition to surface water planning. These utilities are being
studied under the auspices of the Comprehensive Plan 2040.
It should be noted that the land use plan identifies future land use for areas within
the 2040 growth boundary. Service areas for the sewer and water system can be effectively defined by this boundary. In contrast, the surface water system is defined by topography and the drainage that currently moves through the newly
developing areas must continue to be accommodated in the post development condition. For this reason, the modeling and management strategies incorporated
in the LSWMP must deal substantively with the large rural and agricultural areas
that will continue to drain through the City even after build-out of the 2040 Plan. For instance, drainage to Prior Lake extends as far south as the PLSLWD boundary. This drainage extends almost to Cynthia Lake, three miles south of the
growth boundary and incorporates the discharge from Fish Lake, which is over 2.5 miles south of the growth boundary. So, while the 2040 Land Use Plan forms the
basis of the urban system outlined in this report, this urban system is also affected
by large rural drainage areas discharging to Prior Lake.
The comprehensive plan provides a significant amount of narrative and statistical
detail on existing and proposed land use and the reader is referred to that document for more information on land use planning. The hydrologic modeling that
supports the LSWMP used the land use plan to determine hydrologic characteristics of the future landscape. Otherwise, existing land use was used.
Changes from undeveloped land uses, like agricultural and natural, to more heavily developed land uses like low, medium and high density residential, and
commercial have a pronounced effect on hydrology. The increased impervious
surface associated with the urban land uses leads to higher runoff peak flows and increased runoff volume. Table 7.4 shows how volume and peak increase for two typical rainfall events.
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Table 7.4 Land Use Based Peak and Volume Comparisons
Land Use
2-year (2.84”) MSE 3 Atlas 14 24-hour Rainfall 100-year (7.39”) MSE 3 Atlas 14 24-hour Rainfall
Runoff Peak Runoff Volume Runoff Peak Runoff Volume cfs/ac inches cfs/ac Inches Natural 0.2 0.24 3.8 2.5
Agricultural
(row crop in
May and June)
0.9
0.7
5.7
3.8
Low Density Residential
(35% impervious)
1.3
0.9
6.5
4.3
Commercial (85%
impervious)
3.1
2.1
8.7
6.3
The intent of the stormwater management system described in this plan is to reduce the post development peak to a rate more in line with natural conditions. This protects the City’s lakes, wetlands, and channels from erosion and flooding.
The use of volume control is aimed at reducing the post development runoff depth. By reducing the post development runoff depth through infiltration and other
methods – to something more akin to the depths seen off the natural landscape –
lake, wetland and channel protection is augmented. Volume control also provides water quality benefits.
C. Water Resources Data
1. Wetlands
Section 7.3 of this LSWMP provides an in-depth discussion on City’s wetlands and
associated regulations.
2. Lakes
There are 14 named lakes located at least partially within the boundaries of the City of Prior Lake, along with numerous other small, unnamed bodies of water. In
addition, some areas of the City flow to Cleary Lake, located in Credit River Township. Lake information, including watershed area, depth, and surface area, is
provided by PLSLWD. Lakes and wetlands within the City are shown in Appendix
A - Figure 7.8.
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Lake Name DNR ID Shoreland Management
Classification Prior Lake (Upper) 70007200 General Development
Prior Lake (Lower) 70002600 General Development
Spring Lake 70005400 General Development
Pike Lake 70007600 Natural Environment
Campbell Lake 70005600 Natural Environment
Howard Lake 70007300 Natural Environment
Markley Lake 70002100 Recreational Environment
Arctic Lake 70008500 Natural Environment
Jeffers Pond 70007700 Recreational Environment
Haas Lake 70007800 Natural Environment
Blind Lake 70005300 Recreational Environment
Rice Lake 70006000 Natural Environment
Crystal Lake 70006100 Natural Environment
Mystic Lake 70007900 Natural Environment
Upper and Lower Prior Lake
Upper Prior Lake lies between Lower Prior Lake and Spring Lake and is connected to Lower Prior Lake through a channel under County Road 21. Both these lakes have high watershed to lake area ratios and this, particularly is why
they have problems due to nutrient loading. Upper Prior Lake has a surface area of approximately 416 acres and a total watershed area of 16,038 acres – a ratio
of 39 to one. This ratio is extremely high for any water body. Lower Prior Lake
has a surface area of 940 acres and a total watershed area (including that tributary to Upper Prior Lake) of 18,904 acres – a ratio of 20 to one. Both lakes
are relatively deep with a maximum depth of 56 feet in the Lower and 43 feet in
the Upper, although much of upper Prior Lake is shallow, and the lake has an average depth of 10 feet. The Prior Lake outlet channel leaves Lower Prior Lake
at its far western shore near County Road 21. Both Upper and Lower Prior Lake
have a public water access together are one of the top 10 most popular recreational lakes in the state, according to the Minnesota DNR. The land around
both lakes is primarily developed.
Spring Lake
Spring Lake flows to Upper Prior Lake through a natural outlet channel. Its 12,430-acre watershed compares to a lake surface area of 587 acres – a ratio of 21 to one. Spring Lake has a maximum depth of 34 feet and an average depth of
18 feet. Upper and Lower Prior Lakes and Spring Lake all have a substantial amount of residential development around them. Spring Lake has a public water
access.
Pike Lake Pike Lake is a shallow lake through which the Prior Lake outlet channel passes.
Pike Lake has a surface area of 50 acres and a watershed area of 21,770 acres – a ratio of 435 to 1. Although Pike Lake has a large tributary area due to the
outlet channel, Lower Prior Lake has much better water quality than Pike Lake.
An analysis completed for the Prior Lake Outlet Channel EAW showed that Pike Lake tends to have better water quality when the outlet is open compared to
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when it is closed, presumably because the water from Lower Prior Lake dilutes
the high-nutrient levels in Pike Lake. Campbell Lake
Campbell Lake lies northeast of Spring Lake within the jurisdiction of the Scott WMO. Aerial photography and USGS mapping indicate that Campbell Lake
discharges to the northwest through a ditch. It is not known at what elevation this
would occur. The lake’s OHW is 925.5’. Campbell Lake is also characterized by a well-developed wetland fringe and is relatively shallow for a lake though the
actual maximum depth is not known. While much of this lake’s drainage area is
agricultural, some of it is woodland classified as an isolated Natural Area Corridor by Scott County. This lake constitutes the headwaters of Picha Creek.
Campbell lake does not have a public access.
Howard Lake
This lake’s OHW is 957.2 feet. Like Campbell it has large, shallow wetland areas
around its perimeter, and it is not a deep lake though the actual maximum depth is not known. Based on USGS mapping the lake apparently discharges west
into Shakopee though it is not known at what elevation, or how frequently, this
occurs.
Markley Lake Markley Lake straddles the City’s eastern boundary. The lake is landlocked and has historically exhibited a wide fluctuation in water levels. Total lake area is
approximately 22 acres and maximum depth is 22 feet. The contributing watershed is approximately 434 acres. Since it is landlocked the lake must be
carefully managed. The City of Prior Lake Trunk Storm Sewer Fee Determination
Study (February 2001) considered a pumping station and force main from Markley Lake into the Credit River. The City completed the Markley Lake Study
in 2010. The study found that the level of flood protection for Markley Lake could
be minimized to 1991 levels by creating approximately 20 ac-ft of compensatory flood storage. Through a combination of projects, the City has provided 15.9 ac-ft
of compensatory flood storage within the City limits since 2012. The remaining 4.1 ac-ft is targeted for areas outside City limits and should be provided in these areas as properties develop.
Arctic Lake Arctic Lake flows into Upper Prior Lake through a natural outlet channel. Total
lake area is approximately 33 acres with a maximum depth of 30 feet (average of 9.5 feet). Arctic Lake’s 507 acre subwatershed is comprised of woodlands and low to medium-density residential uses. Arctic Lake contributes phosphorus
loading to Upper Prior Lake. A subwatershed analysis report was completed for the lake in 2013 that identified opportunities to reduce this loading. In 2017, the
City, SMSC, PLSLWD, Scott County, and Three Rivers Park District completed a
large collaborative project to connect regional trails and improve water quality in Arctic Lake. The water quality improvements were based on the 2013
subwatershed analysis.
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Jeffers Pond
Jeffers Pond is a deep pond located north of Jeffers Pond Elementary School and east of Eagle Creek Ave NE. The Prior Lake Outlet Channel flows through Jeffers Pond north to Pike Lake. The surface area is approximately 39 acres with
a maximum depth of 70 feet in the westernmost pond. There is a system of public trails and a fishing dock on Jeffers Pond that is only accessible by trail.
Haas Lake Haas Lake is located northeast of Mystic Lake just south of 140th St NW. This is
considered a shallow lake with a maximum depth of less than 8 feet. The total
surface area is around 27 acres. The discharge from the lake flows out of the northwest corner through a culvert under County Rd 42 and into a creek that
empties into the Minnesota River. PLSLWD completed an aquatic survey for the
lake in 2017. General findings identified native shorelines offered good wildlife habitat, low species diversity within the lake, and no non-native plant species
within the lake.
Blind Lake
Blind Lake is located between County Road 21 and State Highway 13 in
southern Prior Lake, within the Scott WMO. The total surface area is about 11 acres. The lake flows to Markley Lake through a series of wetlands and ponds.
There is no public access. Little is known about the characteristics of this lake.
Rice Lake
Rice Lake is located on the southern border of Prior Lake, within the PLSLWD. The lake has a watershed area of 665 acres and a surface area of 30 acres. The
entire shoreline of the lake is wetland fringe. There is not much available
information on water depth or quality, although the lake is classified as a shallow lake by PLSLWD. It flows north into Crystal Lake through a private culvert under
174th Street East in Spring Lake Township.
Crystal Lake
Crystal Lake is located north of Rice Lake in southern Prior Lake, within the
PLSLWD. The lake has a watershed area of 1,340 acres and a surface area of 30 acres. Much of the shoreline around the lake remains in a natural condition
and is part of Crystal Lake Park. The City maintains a popular fishing dock on the
lake that is part of the Minnesota DNR’s Fishing in the Neighborhood (FiN) program.
Mystic Lake Mystic Lake is located east of County Road 83 in the northwestern portion of
Prior Lake. According to the SMSC, Mystic Lake is a 65-acre basin that receives runoff from the Mystic Lake Casino parking lots after it is treated in over 10 acres of stormwater ponds. The SMSC has tracked water quality in the lake since the
late 1990s.
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3. Water Courses
Prior Lake Outlet Channel The Prior Lake Outlet Channel (PLOC) resulted from a citizen petition for an outlet
to carry stormwater from the landlocked Prior and Spring Lakes to ultimately discharge into the Minnesota River. In 1979, the Minnesota Department of Natural
Resources (DNR) issued a permit to the PLSLWD for construction of the Prior
Lake Outlet Channel. The district entered into a joint powers agreement with Prior Lake and Shakopee in 1981 regarding the channel and the outlet system was first
used in 1983. The original outlet structure consisted of a 36-inch RCP pipe
surrounded by a concrete structure with adjustable gates. The outlet structure was rebuilt in 2010 and consists of an accordion-shaped fixed crest weir (set at an
elevation of 902.5) and a low-flow gate allowing discharge between an elevation of
902.5 and 902.0, in accordance with the PLSLWD’s operation plan. The maximum discharge capacity is determined to be 65 cfs, although this discharge rate is only
achieved at very high lake levels above 906.0. The PLSLWD website
(www.plslwd.org) contains more detailed information about the outlet structure and the PLOC.
The PLOC works to address high lake level issues on Prior Lake and as a trunk stormwater system for the City of Prior Lake, the City of Shakopee, and the
SMSC. The PLSLWD, Cities of Prior Lake and Shakopee, and the SMSC operate and maintain the PLOC through a Memorandum of Agreement (MOA).
4. Monitored Water Quality and Quantity Data
The City will continue to support monitoring of surface waters within its
jurisdictional boundaries and the PLOC through the MOA. Data will be obtained through cooperation and coordination with other various agencies, including the
Minnesota Pollution Control Agency, cities and townships adjacent to Prior Lake,
the Metropolitan Council, the Minnesota Department of Natural Resources, the PLSLWD, Scott WMO, and Three Rivers Park District.
Through its own monitoring efforts and those of the Citizen Assisted Monitoring Program (CAMP) run by Metropolitan Council and Three Rivers Park District, the
PLSLWD has been collecting data on nutrient loading into the impaired waters,
and others, identified above.
The PLSLWD water quality data collection and monitoring efforts consist of tributary/outlet monitoring and in-lake monitoring. Tributary/Outlet monitoring, and other sampling occurs at the following locations:
• County Ditch 13 at the second/upstream crossing of Hwy 13 (PLSLWD site
CD 1)
• Outlet of the Hwy 13 Treatment Wetland (PLSLWD site CD2)
• Outlet of the desiltation basin on County Ditch 13 tributary just upstream of Spring Lake (PLSLWD site CD3)
• Outlet from Lower Prior Lake (PLSLWD site PLO)
• Outlet from Spring Lake (PLSLWD site SLO)
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• ST_19 - Tributary to Spring Lake from Scott County Highway Department Watershed
• ST_40 - Tributary to Spring Lake, Outlet of 12/17 Wetland (Spring Lake
Wetland)
• ST_14 - Tributary to Spring Lake, Outlet of Buck Lake
• ST_B3 - Tributary to Fish Lake
• ST_T3 - Tile outlet in Tributary to Fish Lake
• ST_24 - Tributary to Upper Prior - Cates Creek
• ST_S3P and ST_S3PP - Tributary to Lower Prior - Before and After IESF
at Fish Point Park
• ST_26A - Tributary to Pike Lake - along outlet channel in Pike Lake Park
• DLO - Tributary to MN River, where PLOC crosses Highway 101
A total of eight lakes, totaling 10 sample sites, within the PLSLWD were monitored in 2018 as part of the Metropolitan Council’s CAMP. These were:
CAMP Lakes
• Buck Lake
• Haas Lake
• Cates Lake
• Lower Prior Lake (2 monitoring sites)
Three Rivers Park District Lakes
• Lower Prior Lake
• Upper Prior Lake
• Spring Lake
• Pike Lake (2 monitoring sites, East Bay and West Bay)
• Fish Lake
Appendix A - Figure 7.9 shows monitoring stations located within the City. Water
quality information can be found from the watershed management organizations having jurisdiction within the City, Metropolitan Council, and the Minnesota
Pollution Control Agency on the following websites:
• Metropolitan Council monitoring information, including the Citizen-Assisted Monitoring Program (CAMP), can be found at: https://metrocouncil.org/Wastewater- Water/Services/Water-Quality-
Management/Lake-Monitoring-Analysis.aspx
• Prior Lake – Spring Lake Watershed District’s monitoring program
information can be found at:
http://www.plslwd.org/projects-and-programs/monitoring/
• Minnesota Pollution Control Agency’s Citizen Lake Monitoring Program
(CLMP) information can be found at: http://www.pca.state.mn.us/water/clmp.html
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5. Impaired Waters
The Minnesota Pollution Control Agency (MPCA) is required to publish a list of impaired waters; these are lakes and streams in the state that are not meeting
federal water quality standards. For each water body on the list, the MPCA and EPA are required to conduct and approve a study to determine the allowable Total
Maximum Daily Load (TMDL) for each pollutant that exceeds the standards.
Impaired waters in Prior Lake, or those receiving discharge from Prior Lake, are summarized in Table 7.5 and shown in Appendix A - Figure 7.10.
Table 7.5 – Impaired Waters
Water Body
Year First Listed
Affected Use
Pollutant or Stressor
TMDL
Completion
Date
Approved TMDL
Study
Spring (70-
0054)
2002 Aquatic
recreation
Excess
nutrients
2011 Spring Lake – Upper
Prior Lake TMDL
Spring
(70-0054)
1998 Aquatic
consumption
Mercury, FCA 2008 Statewide Mercury
TMDL
Spring (70-
0054)
2018 Aquatic life Fishes
bioassessments
Anticipated
2029
None
Upper Prior
(70-0072)
2002 Aquatic
recreation
Excess
nutrients
2011 Spring Lake – Upper
Prior Lake TMDL
Upper Prior
(70-0072)
2002 Aquatic
consumption
Mercury, FCA 2008 Statewide Mercury
TMDL
Lower Prior
(70-0026)
2002 Aquatic
consumption
Mercury,
FCA
2008 Statewide Mercury
TMDL
Lower Prior
(70-0026)
2018 Aquatic life Fishes
bioassessments
Anticipated
2029
None
Pike
(70-0076)
2002 Aquatic
recreation
Excess
nutrients
Anticipated
2019
None
Cleary Lake 2008 Aquatic Excess nutrients Anticipated None
(70-0022) recreation 2019
Cleary Lake
(70-0022)
1998 Aquatic
consumption
Mercury, FCA 2008 Statewide Mercury
TMDL
Minnesota
River
(07020012-
505)
2004 Aquatic
Consumption,
Aquatic
Recreation
Mercury, PCB’s,
Turbidity,
Dissolved
oxygen (DO)
2006, 2018 Statewide Mercury
TMDL, Lower
Minnesota River DO
TMDL, and
Minnesota River and
Greater Blue Earth
River Basin TSS
TMDL
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 160
Minnesota
River
(07020012-
506)
1998 and
2016
Aquatic
Consumption,
Aquatic Life
Mercury in Fish
Tissue and
Water Column,
PCBs,
Turbidity,
Nutrient /
eutrophication
biological
indicators
2008, 2018 Statewide Mercury
TMDL and
Minnesota River and
Greater Blue Earth
River Basin TSS
TMDL
Notes: FCA stands for fish consumption advisory and is thus not an independent pollutant or
stressor. Source: MPCA
A Lower Minnesota River Watershed TMDL is currently under development. The City will be required to update this surface water management plan to incorporate
the findings of each completed TMDL study and will also be required to amend
their MS4 permit and Storm Water Pollution Prevention Plan. This must be done within 18 months of the approved TMDL date.
The Minnesota River, downstream of the Prior Lake Outlet Channel, is also listed as impaired. This listing will potentially affect management of drainage that directly
discharges to the outlet channel. The river’s affected uses are aquatic consumption, aquatic recreation, and aquatic life and the pollutants or stressors
that have been identified as causing these impairments are the following:
• Fecal coliform
• Low oxygen
• Mercury
• PCB
• Turbidity/TSS
The Minnesota River and Greater Blue Earth River Basin Total Suspended Solids
TMDL was completed in 2018 to address the turbidity impairment for the
Minnesota River and the Greater Blue Earth River basin. The City of Prior Lake
was included in the categorical wasteload allocation for those portions of the
Lower Minnesota River downstream of the PLOC. The categorical TSS load
reductions for the relevant reaches to the City are as follows:
• 07020012-505 – 60%
• 07020012-506 – 74%
• 07020012-800 – 73%
The MPCA approved the TCMA Chloride Management Plan in 2016. This plan is intended to discuss the impacts of chloride on water quality, set performance-based goals, and provide implementation strategies to communities to reduce salt
runoff and usage. This plan can be viewed here: https://stormwater.pca.state.mn.us/index.php/Chloride_Management_Plan
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6. Groundwater
Groundwater resource data for areas within the City is available by reviewing the content of three reports. A brief description of the content for these documents is
provided below along with a web link.
• The Scott County Geologic Atlas completed in 1982 contains information on aquifers, depth to ground water table, and areas sensitive to ground water pollution.
• The Scott WMO Comprehensive Water Resources Management Plan contains groundwater information, issues and policies for Scott WMO.
• City of Prior Lake Wellhead Protection Plan delineates drinking water supply management areas and wellhead protection areas. Appendix A - Figure 7.12 shows the Drinking Water Supply Management Areas (DWSMAs) for the City.
The City’s Wellhead Protection Plan consists of two parts. Part 1 delineates
wellhead protection areas and associated drinking water supply management areas (DWSMAs) and identified two DWSMAs within the City. Part 2 identified
potential contaminant sources within the DWSMAs, and discusses source
management strategies and the goals, objectives, and action plans that accompany these strategies. Some of these goals include:
• Maintaining the current level of water quality so that the municipal water
supply will continue to meet or excess state and federal water quality
standards.
• Protecting source water aquifers through intercommunity collaboration and
data sharing/collection.
• Providing educational material to the public regarding the Wellhead and
Source Water Protection Program.
Specific action items related to these goals can be found in Section 7.6 of this
SWMP. The Wellhead Protection Plan executive summary can be found in
Appendix G. A full version of Parts 1 and 2 can be requested from the City.
The City will be required to incorporate the requirements of the Wellhead
Protection Plan into their SWPPP for areas located within vulnerable source water protection areas (NPDES MS4 General Permit). Vulnerable Source Water
Protection areas are those areas susceptible to water supply contamination from activities at the land surface and are based on the following three components: geologic sensitivity, well construction maintenance and use, and water chemistry
and isotopic composition. DWSMA vulnerability is determined using geologic, soils and groundwater chemistry information. The designation indicates that the aquifer is covered by at least 50 feet of clay material.
For areas of vulnerability, the City will incorporate the guidance developed by the Minnesota Department of Health (MDH) on evaluating proposed stormwater
infiltration projects in vulnerable source water protection areas and the guidance located within the Minnesota Stormwater Manual when designing infiltration best
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 162
management practices (BMPs). This will be of a particular concern in areas where
stormwater infiltration is being considered in soils suitable for rapid infiltration adjacent to municipal and private wells.
Appendix A - Figure 7.17 also shows the surface water/groundwater interaction as analyzed by regional screening performed by the Metropolitan Council in their
report, Evaluation of Groundwater and Surface-Water Interaction: Guidance for
Resource Assessment. The Council intends on completing this process again in the future as new information becomes available. Spring Lake and Upper Prior
Lake are shown to recharge aquifers.
7. Flood Insurance Studies
A Flood Insurance Study, dated March 1978, was completed for the City of Prior Lake by the Federal Insurance and Mitigation Administration, a department of the
Federal Emergency Management Agency (FEMA). This study updated a Flood
Hazard Boundary Map that was prepared by the FEMA in 1975. The 1978 Flood Insurance Study was based on Prior Lake being a land-locked lake, no outlet was
considered in the analysis. The method applied a water mass balance model to generate historic lake levels. That study established a 100-year flood elevation of 908.9 with a 1-foot regulatory freeboard elevation of 909.9 for Prior Lake and a
100-year flood elevation of 914.4 for Spring Lake. In 1997, an approved Flood Insurance Study was prepared by the US Army Corps
of Engineers for the FEMA to determine if the 100-year flood elevation could be lowered for Prior Lake. The City and PLSLWD completed a flood mitigation and
stormwater management study in 2016 that included an analysis of Prior Lake and
its contributing drainage area. In 2018, FEMA approved a new 100-year floodplain elevation for Prior Lake at an elevation of 906.9 (regulatory freeboard elevation of
907.9) based on the results of the 2016 study. FEMA boundaries are shown in
Appendix A - Figure 7.13. The current FEMA maps can be found on FEMA’s website by searching for the Flood Map Service Center.
D. Natural Resources Data
1. MLCCS and MCBS
The Minnesota Land Cover Classification System, or MLCCS, categorizes urban
and built up areas in terms of land cover rather than land use. MLCCS serves as a tool for City staff to integrate natural area preservation into land planning, land
use, and zoning decisions. The City is dominated primarily by developed area with
planted or cultivated vegetation areas as the next majority land classification. The remaining areas are herbaceous areas and wetland throughout the center of the
City. Appendix A - Figure 7.14 provides MLCCS coverage for Prior Lake.
According to the DNR, the Minnesota County Biological Survey (MCBS) began in
1987 as a systematic survey of rare biological features on a county-by-county
basis. Prior Lake has several areas identified as outstanding and high biological significance. These are generally in close proximity to Prior Lake ’s open space
and park land. The DNR has jurisdiction over these areas. Based on state statute
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any work within these areas is required to meet DNR permit requirements.
Appendix A - Figure 7.15 provides the locations of rare and biological features in the City of Prior Lake.
The conservation corridor shown in Appendix A - Figure 7.15 represents area designated by the DNR to be protected and to provide restoration of key natural
habitats. These corridors are to be used by local agencies to prioritize areas for
conservation.
7.3 WETLAND MANAGEMENT PLAN A. Goals
The goal of this Wetland Management Plan is to establish a policy of No Net Loss of wetland area and function, in accordance with the Wetland Conservation Act (WCA).
The plan is designed to achieve the following goals:
1. Achieve no net loss of wetlands;
2. Protect and preserve wetlands through administration and enforcement of the
WCA;
3. Discourage the disturbance of wetlands;
4. Determine the quality of wetlands through the review of wetland assessments
prepared for any project that includes a wetland;
5. Restrict clearing and grading near the wetland boundary and require a protective
buffer strip of natural vegetation to provide protection from stormwater runoff and
promote infiltration of sediment and nutrients;
6. Investigate the establishment of a wetland bank to allow for wetland replacement
for City projects.
7. Identify wetland restoration or enhancement opportunities.
8. Promote wetland stewardship.
B. Wetland Conservation Act Administration
The City of Prior Lake will administer the WCA following the duties and procedures set
forth in Minnesota Rule 8420.0200. A wetland assessment will be required for any project parcel that includes a wetland, as defined by the National Wetland Inventory or other available data.
Wetland-related applications shall be submitted to the Local Government Unit (LGU)
contact. The City may establish fees to offset the costs associated with reviewing
these applications. Upon receipt, the LGU contact or their designee will review the application for completeness within 15 business days. A complete wetland delineation
application includes:
• Wetland Delineation Report completed in accordance with the most current
versions of the US Army Corps of Engineers (USACE) Wetland Delineation Manual and applicable Regional Supplement.
• Determination of wetland function through the application of the most current version of the Minnesota Rapid Assessment Method (MnRAM) for wetlands.
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 164
• Signed Joint Application Form for Activities Affecting Water Resources in
Minnesota.
• Submittal of wetland boundaries via GIS shapefile or CAD file (following
approval)
Wetland delineations shall be completed within the growing season, which is generally
defined as between April 15 – October 15 of any given year. Reports for delineations
within this time frame must be submitted to the LGU by November 1. This period may be extended or reduced at the discretion of the LGU based on local growing season
conditions.
The City of Prior Lake discourages wetland disturbances in accordance with the WCA.
The City requires project proponents to first avoid direct or indirect impacts to wetlands. If avoidance is not feasible, project proponents must minimize impacts. Finally, wetland impacts must be replaced at a minimum 2:1 ratio through either
project-specific (on-site) replacement or the purchase of replacement credits from a Board of Water and Soils Resources (BWSR)-approved wetland bank. A complete application for wetland impacts must include:
• Signed Joint Application Form for Activities Affecting Water Resources in
Minnesota
• Project plans depicting wetland impact area
• Mitigation plan (if required)
The Joint Application Form for Activities Affecting Water Resources in Minnesota is
available on the BWSR website at
http://www.bwsr.state.mn.us/wetlands/wca/index.html.
All complete applications will be noticed to the Technical Evaluation Panel (TEP) for a
minimum 15-day comment period. This comment period may be extended based on the complexity of the review. During this comment period the LGU may hold a meeting
to review the application. In accordance with MN Rules 8420.0240, the TEP consists
of a technical professional employee of the BWSR, a technical professional employee of the Scott County Soil and Water Conservation District (SWCD), a technical
professional with expertise in water resource management and Department of Natural Resources (DNR) for projects that involve DNR Public Waters. Although they cannot officially be part of the TEP, the local watershed district and USACE will be notified of
all complete applications and TEP meetings.
Per Minnesota Statute 15.99, decisions regarding wetland applications must be made
within 60 days of receipt of a complete application. This decision deadline may be extended. Decisions regarding wetland delineations, No Loss, or Exemptions shall be reviewed and approved at the staff level. Decisions regarding replacement (mitigation)
plans and wetland bank establishment plans shall be approved by the City Council. Other agencies may also regulate wetlands. These include, but are not limited to the
DNR, USACE, Minnesota Pollution Control Agency, and local watershed district.
Approval through the WCA does not obviate the need for approval from other regulating agencies. It is the responsibility of the applicant to identify and obtain all
permits or approvals needed prior to construction.
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C. Stormwater Protection
There are many types of wetlands, each determined by its hydrology and vegetative composition. A wetland’s sensitivity to stormwater input is dependent on the wetland’s
community type and the quality of its plant community. Some wetlands (e.g., sedge
meadows with carex species) are sensitive to disturbance and will show signs of degradation unless water quality, bounce and duration are maintained at existing
conditions after construction. On the other hand, there are other wetlands (e.g., floodplain forests) which are better adapted to handle the fluctuating water levels and influx of sediment often associated with stormwater.
Prior Lake’s Public Works Design Manual (PWDM) outlines the allowable uses of wetlands for stormwater utilization. This document divides wetlands into rankings that
include: highly susceptible, moderately susceptible, least susceptible, and slightly susceptible. The following are the procedures that were used to determine the wetland
susceptibility ranking.
Highly Susceptible: A wetland is considered highly susceptible if:
• Forty percent or more of the wetland complex has a highly susceptible wetland
community (-ities) as shown in Table 7.6 and;
• Highly susceptible wetland community (-ities) have medium to exceptional floral diversity/integrity.
Moderately Susceptible: A wetland is considered moderately susceptible if:
• Forty percent or more of the wetland complex has a moderately susceptible
wetland community (-ities) as shown in Table 7.6 and;
• Moderately susceptible wetland community (-ities) have medium to exceptional floral diversity/integrity.
Least Susceptible: Wetlands with low floral diversity, as determined by MnRAM, were least susceptible wetlands.
Slightly Susceptible: Wetlands that do not fall under the high, moderate, or least susceptible categories are considered slightly susceptible.
Table 7.6 Wetland Community Susceptibility to Stormwater Impacts
Highly Susceptible Wetland Communities* Moderately Susceptible
Wetland Communities*
Sedge Meadow Low Prairies Shrub-Carrs
Bogs Coniferous Swamps Alder Thickets
Coniferous Bogs Hardwood Swamps Fresh (wet) Meadows
Open Bogs Seasonally Flooded Basins Shallow Marsh
Calcareous Fens Deep Marsh
* Wetland community (-ities) determined using key provided in MnRAM Version 2.0.
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The following sections provide summaries of each protection strategy developed for
wetlands within the City. Refer to the PWDM for complete details regarding stormwater utilization.
1. Rate Control
Wetlands may be utilized for rate control as long as this use complies with the
bounce and inundation criteria of Table 7.7.
2. Volume Control
In the recent past, surface water management plans have protected wetlands from nutrients but not water fluctuations or duration. In fact, it was common to use
wetlands to reduce flooding potential through sizing storm sewer pipes to maximize bounce and detention time in wetlands.
This plan addresses stormwater quantity impacts to wetlands by providing protection strategies to maintain the existing integrity of the wetland through
special protection strategies for highly, moderately, and slightly susceptible
rankings and are described in Table 7.7 below.
Table 7.7 Wetland Quantity Standards
Hydroperiod
Standard
Highly
Susceptible
Moderately
Susceptible
Slightly
Susceptible
Least Susceptible
Storm Bounce
100-year
Existing Existing
+ 0.5 ft
Existing
+ 1 ft
No limit
Discharge Rate Existing See Rate Control
Standard
See Rate Control
Standard
See Rate Control
Standard
1 & 2-year NRCS
event Inundation
Existing Existing
+ 1 day
Existing
+ 2 days
Existing
+ 7 days
10-year NRCS event Inundation Existing Existing
+ 7 days
Existing
+ 14 days
Existing
+ 21 days
Outlet control
elevation Existing Existing 0-2 ft additional
storage
0-4 ft additional
storage
“Existing” in this chart means the existing hydrologic conditions. If there have been recent significant changes in conditions, it means the conditions that established the current
wetland.
3. Water Quality
Water quality plays a significant role in the overall quality of a wetland. When the
quality of the incoming water declines, the wetland’s plant community may see a
reduction in species diversity and retain only those species that are tolerant of high nutrient and sediment loads. Once a wetland’s plant community is changed,
the wetland’s character and ecosystem will change, often to a less valuable system in terms of biodiversity, habitat for wildlife, and aesthetic enjoyment. Stormwater runoff shall not be discharged into wetlands without pretreatment.
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4. Wetland Buffer and Setback Protection
A wetland buffer is a vegetated area that surrounds a wetland and reduces negative impacts to wetlands from adjacent development. Catch basins and storm
sewers typically collect street and front yard drainage and direct the drainage to an appropriately-sized pond for pretreatment prior to discharge to a wetland or
waterbody. Backyard drainage typically reaches wetlands or waterbodies without
pretreatment, thereby allowing lawn and garden chemicals, sediments, pet wastes, fertilizer and other types of contaminants to directly impact the receiving
waterbody. Wetland buffers can help mitigate potential development impacts to
wetlands by reducing erosion by stormwater; filtering suspended solids, nutrients, and harmful substances; and moderating water level fluctuations during storms.
Buffers also provide essential wildlife habitat for feeding, roosting, breeding, and
rearing of young, and cover for safety, movement, and thermal protection for many species of birds and animals.
For any parcel created or developed in the City, a buffer shall be maintained around the perimeter of all Major Watercourses (as defined by Scott WMO),
watercourses (as defined by PLSLWD), WCA wetlands, and Public Waters wetlands. The buffer features outlined in Tables 7.9 and 7.10 below are required for wetlands and watercourses in the PLSLWD and Scott WMO; buffer
requirements will apply based on the watershed in which the project resides.
Buffer requirements do not apply to any wetland with a surface area equal to or less than the area of wetland impact allowed without replacement as de minimis
under the WCA.
The quality of each wetland can be found using the results of the MnRAM
assessment described in Section 7.2, and defined in Table 7.8:
Table 7.8 MnRAM Wetland Quality Definitions
MnRAM Wetland Classification Wetland Quality Rating
Preserve Exceptional
Manage 1 High
Manage 2 Medium
Manage 3 Low
Table 7.9 Wetland Buffer, Setback and No-Grade Requirements
(areas within PLSLWD)
Buffer
Requirement
Wetland Quality
Exceptional High Medium Low
Average Width (ft) 30 30 30 30
Minimum Width (ft) 20 20 20 20
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Table 7.10 Wetland Buffer, Setback and No-Grade Requirements
(areas within Scott WMO)
Buffer Requirement
Wetland Quality
Exceptional High Medium Low
Average Width (ft) 65 50 35 25
Minimum Width (ft) 25 25 25 25
Minimum No-Grade Zone (ft) 25 25 25 25
Foundation setback
from Wetland
35 35 35 35
Refer to the PWDM for complete standards regarding wetland buffer and setback
protection.
5. Buffer Vegetation
Where acceptable natural vegetation exists in wetland buffers, the retention of such vegetation in an undisturbed state is required unless an applicant receives
approval to replace such vegetation. An existing wetland buffer has acceptable
natural vegetation if it:
• Has a continuous, dense layer of perennial grasses that has been
uncultivated or unbroken for at least 5 consecutive years; or
• Has an overstory of trees and/or shrubs that has been uncultivated or unbroken for at least 5 consecutive years; or
• Contains a mixture of the plant communities described in the two preceding paragraphs that has been uncultivated or unbroken for at least 5
consecutive years.
Notwithstanding the performance standards set forth in this section, the City may determine the existing buffer vegetation unacceptable if:
• It is composed of undesirable plant species including but not limited to Prohibited and Restricted Noxious Weeds listed by the Minnesota
Department of Agriculture in the current Noxious Weed List; or
• It has topography that tends to channelize the flow of runoff; or
• For some other reason it is unlikely to retain nutrients and sediment.
Where wetland buffers are not vegetated or have been cultivated or otherwise disturbed within 5 years prior to the project application, such areas shall be
replanted and maintained. The wetland buffer plantings must be identified within
the application materials. Wetland buffers shall be established in accordance with the following standards:
• Buffers shall be planted with a seed mix included on the current State Seed
Mix list.
• Seed mixes shall be broadcast in accordance with the State Seed Mix specifications of the selected mix.
• The selected seed mix shall be appropriate for the site soil conditions and free of invasive species.
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• Native shrubs may be substituted for native forbs. All substitutions must be
approved by the City. Such shrubs may be bare root seedlings and shall be planted at a minimum rate of 60 plants per acre. Shrubs shall be distributed
to provide a natural appearance and shall not be planted in rows.
• Any groundcover or shrub plantings installed within the buffer are
independent of any landscaping required elsewhere by the City.
• Grasses and forbs shall be seeded or planted using a method of application
that shall be approved by the City prior to planting or seeding.
• No fertilizer shall be used in establishing new buffer strips, except on highly
disturbed sites when necessary to establish acceptable buffer vegetation
and then limited to amounts indicated by an accredited soil testing laboratory.
• All seeded areas shall be mulched immediately with clean straw at a rate of 1.5 tons per acre or as specified by the agency specifications for the seed
mix being used. Mulch shall be anchored with a disk or tackifier.
• Buffers (both natural and created) shall be protected by erosion and
sediment control measures during construction in accordance with the
PWDM. The erosion and sediment control measures shall remain in place until permanent cover, as defined by the current NPDES Construction
Stormwater Permit, is achieved.
A 2-year maintenance period is required as part of the developer’s agreement or other City agreement. During the first two full growing seasons, any buffer
vegetation that does not survive must be replanted. The owner shall be responsible for reseeding and/or replanting if the buffer changes at any time
through human intervention or activities. At a minimum, the buffer strip must be
maintained as a “no mow” area.
Buffer strips shall be required regardless of whether the wetland is on the same parcel as the proposed development or on an adjacent parcel. Wetlands on
adjacent parcels need not be delineated, but an estimation using aerial photos or
other desktop resources will be required.
Refer to the PWDM for complete standards regarding wetland buffer vegetation requirements.
6. Buffer Monuments
Buffers shall be identified within each parcel by permanent monumentation.
Monuments shall be required at each parcel line where it crosses a buffer and shall have a maximum spacing of 200 feet along the edge of the buffer. Additional
monuments shall be placed as necessary to accurately define the edge of the
buffer. Signage requirements and fees are outlined in the City’s PWDM.
7. Buffer Protection Conservation Easements and Outlots within Scott WMO
Within the Scott WMO, property owners shall submit to the City for its approval a
conservation easement for protection of approved buffers, or include the buffer in an outlot, dedicated to the City, as part of platting and subdivision approval.
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Conservation easements shall describe the boundaries of the wetland or public
waters wetland and buffer, identify the monuments and monument locations, prohibit removal of the buffer monuments, and prohibit any alterations set forth in in ‘Prohibited Buffer Alterations’ below. Approved conservation easements must
be filed for record and evidence of filing must be submitted to the City. Outlot descriptions shall provide for an equivalent level of protection of the buffer and
prohibit any alterations set forth in ‘Prohibited Buffer Alterations’ below.
Conservation Easements within PLSLWD
Within the PLSLWD, property owners shall submit to the PLSLWD for its approval
a conservation easement for protection of buffers. Conservation easements shall describe the boundaries of the watercourse or wetland and buffers, identify the
monuments and monument locations, prohibit removal of the buffer monuments,
and prohibit any alterations set forth in section 3.3.8 below. Approved conservation easements must be filed for record and evidence of filing must be
submitted to the PLSLWD.
8. Buffer Alterations
Prohibited Buffer Alterations Subject to ‘Permitted Buffer Alterations’ below, alterations including building,
storage, paving, mowing, plowing, introduction of Prohibited and Restricted Noxious Weeds listed by the Minnesota Department of Agriculture in the current Noxious Weed List, cutting, dredging, filling, mining, dumping, grazing livestock,
agricultural production, yard waste disposal or fertilizer application, are prohibited within any buffer. Prohibited and Restricted Noxious Weeds may be removed.
Alterations do not include plantings that enhance the natural vegetation or
selective clearing or pruning of trees or vegetation that are dead, diseased, or pose similar hazards.
Permitted Buffer Alterations The following activities shall be permitted within any buffer, and shall not constitute
prohibited alterations under ‘Prohibited Buffer Alterations’ above:
• Use and maintenance of an unimproved access strip through the buffer, not
more than 20 feet in width, for recreational access to the watercourse or
wetland and the exercise of riparian rights;
• Placement, maintenance, repair or replacement of utility and drainage
systems that exist on creation of the buffer or are required to comply with any subdivision approval or building permit obtained from the City, so long as any
adverse impacts of utility or drainage systems on the function of the buffer
have been avoided to the extent possible;
• Construction, maintenance, repair, reconstruction or replacement of existing
and future public roads crossing the buffer, so long as any adverse impacts of the road on the function of the buffer strip have been avoided or minimized
to the extent possible;
• Clearing, grading, and seeding is allowed if part of an approved Wetland
Replacement Plan.
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D. Wetland Restoration/Enhancement Opportunities
It is a goal of this plan to identify wetland restoration and enhancement opportunities and achieve no net loss of wetlands within the City.
The WCA requires replacement for wetland impacts a minimum 2:1 ratio through
either site- specific replacement or through the purchase of credits through a BWSR-
approved wetland bank. Site-specific replacement should be encouraged when a wetland restoration or creation is possible on-site. When site-specific replacements
are not ecologically appropriate, then wetland banks located within the City and
County should be the next priority. Currently, there are no wetland banks within the City of Prior Lake. It is a goal of this section and outlined in Policy 6.5 of this plan to
investigate the establishment of a wetland bank for use by the City to mitigate for
wetland impacts within the City.
In January 2017, the City prepared a study that identified potential wetland bank sites.
Five sites were identified, three of which had characteristics that would make wetland mitigation bank development feasible. Two of these sites are not currently owned by
the City. The City does maintain a conservation easement over the third site. A site visit and initial coordination with the WCA TEP occurred in Spring 2017. Additional coordination with the TEP and USACE is needed to further identify mitigation bank
potential.
E. Wetland Stewardship
There are a number of things that can be done by individuals or groups to enhance
wetlands, buffer strips that surround wetlands, shorelands, or high-quality upland
areas. This section describes some of these practices. It is recommended that individuals and groups contact the City prior to doing any work within wetlands or
buffers.
1. Enhancement
Native wildflowers, grasses, shrubs and trees can be planted in the wetland or the adjacent buffer areas to enhance habitat and stormwater filtering. Habitat can be
enhanced by creating vertical layers (planting trees or shrubs where these are absent), and by adding plants that provide food and cover, such as fruiting shrubs. Increasing the structural and plant species diversity in the landscape provides
additional habitat niches and can increase the numbers and species of animals using the area.
Species that are native to the area will probably require the least maintenance, survive harsh Minnesota weather more easily, and provide the greatest habitat
benefits. The DNR has information available to assist the public with landscaping
using native plants: http://www.dnr.state.mn.us/gardens/nativeplants/index.html.
Structures for nesting and basking can also be added to wetlands and buffer areas to enhance the habitat availability for wildlife. The Minnesota DNR, Minnesota
Waterfowl Association, and other habitat enhancement organizations can provide
information about the types and sources of structures available. Cost-share may
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be available from local organizations including the Scott WMO, PLSLWD, and
Scott SWCD. 2. Control of Invasive Species
Several non-native (invasive) species have become problems in Minnesota
wetlands and adjacent uplands. These plants invade native plant communities and
can take over rapidly, eliminating native plants that provide important food and habitat benefits.
Information related to the identification and control of invasive species is available through the DNR: http://www.dnr.state.mn.us/invasives/terrestrialplants/index.html.
The State Noxious Weed list is available from the Minnesota Department of Agriculture: https://www.mda.state.mn.us/plants-insects/minnesota-noxious-weed-
list
3. Encouraging Pollinators
The City of Prior Lake recognizes the importance of pollinators for assisting in the reproduction of plants. The City is interested in managing for pollinators and
increasing awareness for pollinators and the benefits they provide. Managing for pollinators includes a series of steps necessary to create, restore, or
enhance a designated area to provide the necessary habitat to various pollinators (e.g. bees, butterflies, certain bird species, bats). Strategies include ensuring
sufficient foraging habitat, providing structures or host plants needed for
reproduction, providing shelter, and minimizing the use of chemicals to control invasive species. The City may also provide educational opportunities to area
residents to increase awareness for pollinators and encourage individuals and
groups to adopt pollinator-friendly practices.
4. Education
The City intends to continue to provide educational opportunities to the public, and
currently hosts periodic workshops and events aimed at educating the public on water quality and water resources. The City also provides information on stormwater and wetland-related topics in the City’s newsletter.
Schools and other organizations can adopt wetlands and adjacent areas for use as outdoor classrooms. Students, parents, and teachers can add native wetlands
and upland plants, habitat structures, and other enhancements to increase learning opportunities and encourage other wetland owners in the area to make
similar enhancements.
5. Climate Change Resiliency
Studies have indicated that climate change may cause more frequent, extreme, weather events. Wetlands, some of which serve as areas for flood retention, may
be overwhelmed by these weather events. Additionally, native plant species may
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not compete well against invasive species under changing climate conditions,
which may adversely affect plant and wildlife habitats. Developing sustainability goals and preparing for greater climate variability and
extreme weather events can help to facilitate a faster response when these events occur. These efforts may include identifying potential flooding scenarios,
developing a flood reduction target, and assessing the cost and benefits of
infrastructure needs to achieve the target. In addition, efforts to reduce emissions and energy usage can be used to help the City reach its sustainability goals.
Examples of such efforts include: recycling/composting programs, native plant
sales, LED lightbulb promotion, energy workshops, non-motorized transportation availability, and electric vehicle plug-in parking.
7.4 AGENCY COOPERATION
There are a number of local, State, and Federal agencies that have rules and
regulations related to local surface water management. The City recognizes the roles of these other agencies and will cooperate, coordinate, and when possible partner with
these agencies. This section describes the City’s current surface water management program and practices and identifies the agencies and organizations having roles in the City’s management of these resources. Table 7.11 summarizes the City’s and other
agencies’ respective regulatory controls related to water resources management and protection.
A. City Ordinance, Policy, and Procedures
Prior Lake supports its comprehensive plan with infrastructure plans. These
infrastructure plans detail future sanitary sewer, water, transportation, and surface water systems that must be built to fulfill the land use plan. This LSWMP serves as the
infrastructure plan for surface water systems. Beyond its role in the comprehensive
plan update, the LSWMP has a broader regulatory context that includes meeting statutory, rule, and watershed requirements.
The Public Works Department is responsible for the planning, administration, design and inspection of infrastructure improvements. This department coordinates with
outside agencies in water resource management and conservation. They also provide monitoring and maintenance of storm sewers, ponding areas, water quality devices and other BMPs. The Prior Lake Planning Department manages comprehensive
planning and administers the zoning code within the City, which includes land use, zoning, transportation, sewer extension and community facility improvements.
Current regulations and policies that govern surface water management within Prior Lake include the engineering design standards and previous surface water
management plans. Table 7.11 summarizes the City’s regulatory controls regarding
surface water.
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Table 7.11 – Regulatory Control Official Control Responsibility Mechanism
Stormwater
Management
City, WD, WMO City Ordinance Section 1004: Design
Standards; Public Works Design
Manual
Erosion and Sediment Control City, WD, WMO, PCA City Ordinance Section 1004: Design Standards; Public Works Design
Manual
Shoreland City, WD, WMO,
DNR
City Ordinance Section 1104:
Shoreland Regulations
Floodplain City, WD, WMO,
DNR
City Ordinance Section 1105:
Floodplain Regulations Wetlands City as LGU, DNR, USACE & BWSR,
WD
City regulates, WCA source/delegated. TEP = DNR, BWSR, SWCD, Corps is separate process, WD regulates buffer conservation easements
Illicit Discharge City, WD City Ordinance Section 1004: Design Standards; Public Works Design Manual; WD within the PLOC
Grading and Drainage City, WD, WMO City Ordinance Section 1004:
Design Standards; Public Works
Design Manual
Public Waters City, DNR, Scott
County
City Ordinance Section 703: Public
Waters *Acronyms are defined in the sections below
City staff is supported by commissions and committees. These include:
• Planning Commission – reviews all applications for development and
recommends approval or denial based on conformance with the comprehensive plan and zoning regulations.
• Citizen Engagement Committee – performs outreach and education within the community for a wide range of topics including those relating to water resources
and surface water management.
B. Support Agencies This plan is in conformance with but does not restate all other agency rules that are
applicable to water resource management. The following agencies deal with or regulate water resources throughout the City.
● Scott County https://www.scottcountymn.gov/
● Prior Lake- Spring Lake Watershed District https://www.plslwd.org/
● Scott Watershed Management Organization
https://www.scottcountymn.gov/746/Watershed-Management-Organization
● Scott County Soil and Water Conservation District
https://www.scottswcd.org/
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2040 Comprehensive Plan Page 175
● Minnesota Department of Health www.health.state.mn.us
● Minnesota Pollution Control Agency www.pca.state.mn.us
● Board of Water and Soil Resources www.bwsr.state.mn.us and the Wetland Conservation Act www.bwsr.state.mn.us/wetlands/wca/index.html
● Minnesota Department of Natural Resources (DNR) www.dnr.state.mn.us
● US Army Corps of Engineers www.mvp.usace.army.mi
● Minnesota Department of Agriculture www.mda.state.mn.us
● US Fish and Wildlife Service www.fws.gov
● Minnesota Environmental Quality Board www.eqb.state.mn.us
● Metropolitan Council www.metrocouncil.org
● Minnesota Department of Transportation (MnDOT) www.dot.state.mn.us/
● U.S. Environmental Protection Agency (EPA) https://www.epa.gov/
● Federal Emergency Management Agency (FEMA)
https://msc.fema.gov/portal
● Natural Resources Conservation Service (NRCS)
https://www.nrcs.usda.gov/
● U.S. Geological Survey (USGS) https://www.usgs.gov/
While these other agencies’ rules, policies, and guidelines are not all restated in this Plan, they are applicable to projects, programs, and planning within the City. The
MPCA Minnesota Stormwater Manual, which is a document intended to be frequently
updated, is also incorporated by reference into this Plan and can be found at www.pca.state.mn.us/water/stormwater/stormwater-manual.html.
C. NPDES Permitting Process
The MPCA has designated the City of Prior Lake as an NPDES Phase II MS4
community (MN Rules Chapter 7090). Prior Lake’s application for permit coverage was extended in 2014. The permit outlines Prior Lake ’s Stormwater Pollution
Prevention Plan (SWPPP) to address six minimum control measures:
• Public education
• Construction site runoff control
• Public involvement
• Post-construction runoff control
• Illicit discharge detection and elimination
• Pollution prevention in municipal operations
The City’s SWPPP contains several best management practices within each of the listed control measures. These were identified using a self-evaluation and input
process with City staff. The most recent 5-year permit cycle required cities to reapply for coverage in the Fall of 2018. Permit coverage was extended to Prior Lake in 2014 for the current 5-year permit cycle.
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Many of the goals and policies discussed in this local surface water management plan
are directly related to requirements listed as part of the MS4 program. As a result, the implementation section of this plan repeatedly references items listed in the City’s MS4 SWPPP.
Along with the City’s MS4 permit requirements, the MPCA also issues permits to
construction site owners and operators to prevent stormwater pollution during and
after construction. The National Pollutant Discharge Elimination System (NPDES) Construction Stormwater General Permit regulates any stormwater runoff from
construction sites. An NPDES permit is needed if the following activities are triggered:
• Disturbing one acre or more of soil.
• Disturbing less than one acre of soil if that activity is part of a "larger common plan of development or sale" that is greater than one acre.
• Disturbing less than one acre of soil, but the MPCA determines that the activity poses a risk to water resources.
The NPDES Construction Stormwater General Permit was reissued on August 1, 2018.
D. Comparison of Regulatory Standards
Developing property within Prior Lake is subject to review and approval from the two watersheds covering the City (Appendix A - Figure 7.11). Each watershed has
established rules or standards governing stormwater management and protection of
natural resources. Currently these rules vary in content between agencies and may be more restrictive than City standards.
1. Prior Lake- Spring Lake Watershed District (PLSLWD)
The Prior Lake – Spring Lake Watershed District (PLSLWD) defers permitting
authority for most projects to the LGUs and requires local municipalities to adopt standards equivalent to the PLSLWD standards. A copy of the most recent rules is
located in Appendix D. The District’s Water Resources Management Plan was adopted in 2010 and
revised in 2013. This Plan details the goals and policies of the District and provides the foundation for its activities and projects. It identifies problems and short-term strategies and goals. A link to the most recent plan is located above.
2. Scott Watershed Management Organization (WMO)
The Scott Watershed Management Organization (WMO) defers permitting authority to the LGUs and requires local municipalities to adopt standards
equivalent to the Scott WMO standards. A copy of the most recent standards is
located in Appendix E.
The Scott WMO has completed the process of updating their Comprehensive
Water Resources Management Plan and will adopt it in late 2018. Plan implementation will begin starting January 2019.
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E. Water Resource Related Agreements
This section summarizes those water resources related agreements the City of Prior Lake has established with other entities.
1. Prior Lake Outlet Channel MOA
The City of Prior Lake is party to a 2006 Memorandum of Agreement (MOA)
with the City of Shakopee, PLSLWD, and the Shakopee Mdewakanton Sioux Community (SMSC) regarding the operation and management of the outlet
channel for Prior Lake. A copy of the MOA is attached as Appendix I.
2. PLSLWD Equivalency Rules
To be updated with new equivalency agreement. Assessment of equivalency
will be conducted upon completion of the PLSLWD rule revisions and any necessary revisions to the City’s ordinances and PWDM.
3. Scott WMO Equivalency Rules To be updated with new equivalency agreement if needed.
7.5 ASSESSMENT OF PROBLEMS AND ISSUES A. Stormwater Management System Assessment
Previous sections of this Local Surface Water Management Plan (LSWMP) provide background on the physical and regulatory forces shaping surface water management
in Prior Lake. This section describes problems and challenges of specific waters,
neighborhoods or programs identified by the City, watershed districts and others. Minnesota Statutes and Rules and Metropolitan Council guidance documents require "issues and corrective actions" or "problems and corrective actions" as elements of
Local Surface Water Management Plans. The assessment includes stormwater management issues, current and future, identified by the City, the two watersheds with
jurisdiction within the City, and other state and federal agencies. Prior Lake
emphasizes the surface water management challenges ahead and that these challenges will test the City’s financial and technical resources. Appendix A - Figure
7.16 provides locations for specific issues throughout the City.
B. Water Quality
1. Issue: Spring Lake, Upper Prior Lake, Lower Prior Lake and Cleary Lake were placed on the MPCA’s impaired waters list for high mercury concentrations in fish. Corrective Action: The EPA has approved the statewide TMDL mercury study. The MPCA has since prepared a plan to reduce mercury releases by 2025. This plan describes specific strategies that the State will employ to achieve the goals of
the TMDL. No additional action by the City is needed.
2. Issue: Spring Lake, Upper Prior Lake, Pike Lake and Cleary Lake are on the
MPCA’s impaired waters list for excess nutrients.
Corrective Action: Prior Lake-Spring Lake Watershed District completed the
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TMDL report and TMDL Implementation Plan for Spring Lake and Upper Prior
Lake in 2011. Site-specific eutrophication criteria were also approved for Spring Lake in 2016. The site-specific water quality standards set a different goal condition for Spring Lake than the ecoregional water quality standards; the new
goal reflects pre-European natural conditions.
Clearly Lake and Pike Lake are included in the Lower Minnesota WRAPS that has
been completed in 2018. The final plan is expected to be officially approved in 2019.
The City will continue to collaborate with Scott WMO and PLSLWD to implement
the recommended strategies outlined in the Lower Minnesota WRAPS and the Spring Lake and Upper Prior Lake TMDL Implementation Plan. Specific projects identified at this time are listed in Table 7.12 of this Plan.
3. Issue: Spring Lake and Lower Prior Lake were placed on the MPCA’s impaired waters list for fish bioassessments in 2018.
Corrective Action: The City will update this plan to include new information
provided by the MPCA or DNR as it becomes available. No additional action by the City is needed.
4. Issue: It is anticipated that there may be additional, future impaired waters listed
that will affect the City.
Corrective Action: The City will work with PLSLWD, Scott WMO, MPCA and
others to develop and implement future TMDLs or other similar water quality-related planning efforts that affect the City.
5. Issue: The possibility of contamination exists when there are connections between groundwater and surface water.
Corrective Action: The City has developed a Wellhead Protection Plan which identifies DWSMAs and their vulnerability. The City will continue to follow the
requirements of its Wellhead Protection Plan to protect groundwater. Guidance
from the MPCA and MDH will be followed to determine the applicability of infiltration in the DWSMAs.
The City will also cooperate with Scott County and Scott WMO on the completion of an assessment of the Prior Lake Drinking Water Supply Management Area
(DWSMA). This assessment would provide a methodology for identifying probable locations of abandoned/unsealed wells and would be used to target contacts for
the well sealing cost share practice implementation. Additional information can be
found in the Scott WMO Watershed Plan.
6. Issue: The Minnesota River has been identified by the MPCA as an impaired
water. Impairments include mercury, PCBs, dissolved oxygen (DO), and turbidity.
Corrective Action: The EPA has approved the statewide TMDL mercury study and no additional action by the City is needed. The Minnesota River and Greater
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Blue Earth River Basin TSS TMDL was completed in 2018, which delegated a
categorical wasteload allocation to Prior Lake to reduce TSS prior to discharging to the Lower Minnesota River. A WRAPS study is currently underway, which would outline implementation measures to be completed to meet the TMDL
requirements. The City will look to implement projects from this report once it has been approved.
7. Issue: In 2016, the EPA approved the Twin Cities Metropolitan Area (TCMA) Chloride TMDL Study. The study established an allowable chloride concentration
and a categorical wasteload allocation has been established for the permitted
MS4s within each impaired watershed.
Corrective Action: The City will continue to follow their Winter Maintenance
Policy for deicing practices and chloride management. New and more efficient deicing practices will be researched to reduce the amount of chloride used for
roads and walkways.
8. Issue: Poor water quality has been monitored in Arctic Lake.
Corrective Action: The City will partner with PLSLWD and SMSC to implement BMPs listed in the Arctic Lake Subwatershed Assessment and BMP Retrofit
Analysis. Specific projects are listed in Table 7.12.
C. Flooding and Stormwater Management
1. Issue: The culvert under Jeffers Pass leading into Jeffers Pond has been observed to become clogged with debris placed by beavers, reducing the hydraulic capacity of the pipe. Additionally, the homes on the upstream side of the
culvert lie below the road EOF, therefore are in danger of flooding when the culvert does not function as designed.
Corrective Action: Install a grate or barrier to prevent the build-up of debris placed by beavers. This may include an outlet improvement on the downstream
side of the culvert as well. These actions will be consistent with the MOA between
PLSLWD and the City. 2. Issue: The culvert north of Island View and under the trail by Arctic Lake near the intersection of Fremont Ave and 82nd St frequently becomes blocked with debris and carp.
Corrective Action: The City will upgrade the structure and coordinate with the
PLSLWD and DNR as needed. This will be a City funded project.
3. Issue: Culvert under Glynwater Trail NW may be undersized. Additionally, when the culvert is blocked with debris, the EOF is over the roadway. Homes on the
upstream side of the culvert are in danger of flooding.
Corrective Action: An outlet improvement project will be completed to provide an overflow structure with an improved skimmer. The outlet will also include
preventative measures to prevent beavers from blocking the outlet. The City will
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also complete an analysis to replace the undersized culvert.
4. Issue: The outlet at Wildwood Pond near Woods at the Wilds Park has the potential to become plugged and the resulting high-water levels could impact
nearby homes.
Corrective Action: An outlet improvement project will be completed to provide an
overflow structure with an improved skimmer. The outlet will also include
preventative measures to prevent beavers from blocking the outlet.
5. Issue: The channel that flows to the Priorwood Street pond is subject to ice
buildup in the winter/spring and regularly floods.
Corrective Action: The City will complete a feasibility study to determine if a realignment of the channel is possible.
6. Issue: The south wetland near Fountain Hills Drive continues to wash out and overwhelm structures through the ravine.
Corrective Action: This issue will be addressed as development occurs. The City
will continue to provide ongoing maintenance until such time of development.
7. Issue: The outlet of the wetland west of Northwood Road near Linden Circle is not
functioning properly and has issues with the structure that maintains water levels.
PLSLWD has observed carp using the wetland as a possible spawning area. The Minnesota DNR formerly used the wetland as a northern pike rearing pond and
was responsible for the existing gate installation.
Corrective Action: An outlet improvement project will be completed to provide an
overflow structure with an improved skimmer that will better maintain the water level. The outlet will also include preventative measures to prevent beavers from blocking the outlet. This work may also include a carp grate installed in
cooperation with the PLSLWD.
8. Issue: The ravine along Shady Beach Trail currently drains through a city easement and experiences drainage issues.
Corrective Action: The City will complete a feasibility study to determine the best options for drainage mitigation.
9. Issue: The pond located near County Road 21 and Adelmann Street currently has an outlet that is not functioning properly. Backups can occur that cause flooding
near the adjacent structures. Both ponds also have a significant population of
cattails which could indicate that the ponds need to be cleaned out.
Corrective Action: The City will complete a survey of the pond and perform a pond cleanout project as necessary.
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10. Issue: The lakes within the City, including primarily Spring Lake and Prior Lake,
experience periodic flooding.
Corrective Action: The City will adhere to its Flood Response Policy, adopted in 2017, when responding to lake flooding events. The City will evaluate and update
the Flood Response Policy on a regular basis. Additionally, the City will work with
local government agencies, including the PLSLWD and Spring Lake Township, to implement the recommended corrective actions per the Prior Lake Stormwater
Management and Flood Mitigation Study (2016). 11. Issue: City streets experience temporary flooding due to intense rainfall events.
Portions of the storm sewer system may be undersized or in need of repair. This type of flooding can lead to public safety hazards, property damage, and sediment discharges to receiving waters.
Corrective Action: The City will create a stormwater system model to identify problem areas and needed system repairs/upgrades.
12. Issue: The outlet of Crystal Lake, located near the intersection of Village Lake
Drive and Panama Avenue (County Road 23), can become clogged with debris, potentially leading to high water in the entire Crystal Lake drainage area. High
water on Crystal Lake due to a clogged outlet has the potential to flood Panama
Avenue.
Corrective Action: An outlet improvement project will be completed to provide an overflow structure with an improved skimmer that will better maintain the water level. The outlet will also include measures to prevent beavers from blocking the
outlet.
13. Issue: A series of ponds located near Priorwood Lane and Kestrel Lane frequently
experience blockage issues that flood the trail and brings high water levels near existing structures.
Corrective Action: A feasibility study will be completed to analyze improvements
to drainage paths and options to reduce pond flooding.
14. Issue: A small pond near Deerfield Lane occasionally floods due to lack of capacity due to sediment deposits.
Corrective Action: The City will complete a survey of the pond and evaluate the
need for a pond cleanout project to remove any deposited sediment. The City will
also consider other options to add capacity such as removing the outlet between the adjacent pond to allow for more storage.
D. Adequacy of Existing Regulations and Programs to Address Adverse Impacts on Local Water Resources
1. Issue: The City has adopted ordinances related to floodplain regulation, illicit discharge, surface water management, native vegetation planting, wetland management and erosion and sediment control. These ordinances need to be
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kept up to date as requirements change. A copy of the ordinances can be found in
Appendix C. Corrective Action: The City will continually evaluate these ordinances and will
update them as needed. The City will continue to enforce all ordinances as necessary.
2. Issue: The City currently has limited funding sources available to complete projects related to water resources.
Corrective Action: Stormwater funds and special assessment funding are not
adequate to implement the studies, programs, and capital improvements outlined
in this plan. The City must apply for grants to fund the implementation of capital improvements identified in this management plan. The City will consider
increasing the current stormwater utility rate to fund future implementation items.
E. Erosion and Sediment Control
1. Issue: Cates Creek, originating on the north side of TH 13 east of Creekside Cir SE and discharging to Upper Prior Lake near the intersection of Green Heights Trail and Dutch Avenue SE, should be monitored for erosion.
Corrective Action: The City will continue to monitor Cates Creek.
2. Issue: There are significant erosion issues on a City-owned parcel on the south side of Markley Lake (PID 255280020).
Corrective Action: The City will provide short term stabilization measures as needed. The long-term goal for this area will be to stabilize an eroding ravine and
provide additional flood storage as well.
3. Issue: The culvert at the north end of Haas Lake under County Road 42 requires frequent maintenance due to an excess of sediment causing blockage in the pipe.
Corrective Action: The City provides frequent maintenance to clean out the contributing drainage channel and will continue to coordinate with the County on
this issue. The County infrastructure may require repairs or modifications to ensure long-term function.
F. Impact of Land Use Practices and Development 1. Issue: Lack of space for stormwater management BMPs on individual
redevelopment or road reconstruction projects.
Corrective Action: The City will work with PLSLWD and Scott WMO to ensure
local stormwater management requirements are met for each project. Alternatives to on-site BMPs may be proposed on a site-by-site basis. The City must also
ensure that all State stormwater management requirements are met for each site.
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2. Issue: Subsurface sewage treatment systems (SSTSs) have the potential to
contaminate surface and groundwater. Corrective Action: The City will ensure SSTS are properly abandoned within 1
year of the extension of new services. Procedures will follow the City’s ordinances.
3. Issue: Wetland degradation caused by agriculture or urbanization.
Corrective Action: The City will implement WCA requirements for any
development or agricultural practice that has the potential to cause wetland
degradation.
4. Issue: Increase in runoff volume as development occurs Corrective Action: To assess the impact development might have on water levels
in Prior Lake, the PLSLWD created a calibrated model of the watershed. The most
effective mitigation strategies, other than removing the homes, are retention storage in the watershed and volume control measures.
5. Issue: Development near Campbell Lake has the potential to impact the sensitive resources for Picha Creek downstream.
Corrective Action: The City will partner with Scott WMO to complete a study that
would assess potential issues with development and identify potential
opportunities for regional stormwater management.
G. Education Program 1. Issue: The City recognizes the need for local water education programs to
increase public awareness of local water management and improve the quality of
stormwater runoff. An education program is one of the requirements of the City’s MS4 Stormwater Pollution Prevention Program (SWPPP).
Corrective Action: The City will continue to provide educational content and opportunities to residents, businesses, developers, and others. These efforts may
include regular notices in the City's monthly newsletter, articles in the local paper, postings on the City website, and flyers in the utility bill. The City will coordinate with PLSLWD and the Scott WMO (including the Scott Clean Water Education
Program) to improve the efficiency of educational efforts and reduce duplication. Educational topics may include, but are not limited to:
• Stormwater pond function and maintenance
• Wetland buffers
• Yard/pet waste management
• Illicit discharge to stormwater
• Utility easements related to location, purpose, encroachments/obstruction • Controlling invasive species
• Erosion and sediment control on small scale landscaping projects adjacent
to impaired waters
• FEMA floodplain issues
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• Water Surface Use Management (WSUM) and water-based recreation
• Salt usage
• Benefits and care of native vegetation
• Groundwater issues
H. Identification of Potential Problems to Occur in the Next 20 Years
1. Issue: Inspecting and maintaining existing stormwater infrastructure throughout the City.
Corrective Action: The City of Prior Lake is responsible for maintenance of its stormwater system in conformance with the MPCA’s MS4 Program. This includes
maintenance of pipes, inlets, outlets, constructed ponds, ditches, swales, and other City stormwater infrastructure. Proper maintenance will ensure that the
stormwater system continues to provide the necessary flood control and water
quality treatment. The City will continue to refine its comprehensive stormwater infrastructure inspection program which is the primary means to identify issues
and prioritize needed stormwater infrastructure repairs. Refer to Appendix B for a
copy of the City’s MS4 SWPPP.
2. Issue: Presence of polycyclic aromatic hydrocarbons (PAHs) in stormwater ponds
from runoff of roadways and other surfaces.
Corrective Action: As stormwater ponds are inspected and maintained, the City will identify any ponds that are contaminated with PAHs and follow MPCA protocol for disposal of dredged material. The State of Minnesota banned the use and sale
of coal tar- based sealants for paved surfaces in 2014 but PAHs deposited in stormwater ponds before that time are expected to persist until they are manually removed during stormwater pond maintenance activities. There is an increased
cost associated with removing PAHs from stormwater ponds as contaminated sediment is considered a hazardous material and must be landfilled.
3. Issue: Accumulation of debris and material on City streets.
Corrective Action: The City will continue to sweep debris and salt from streets in
accordance with the City’s Street Sweeping Policy. Enhanced street sweeping, including targeting the watersheds of impaired lakes and other undertreated areas
within the City, is part of the Policy. More information regarding street sweeping
activities can be found in Appendix H.
4. Issue: Elevated levels of chloride concentrations have been found in stormwater ponds, surface water bodies, and groundwater throughout the Twin Cities Metro Area. At levels exceeding the water quality standards, chloride can be toxic to
aquatic life and can make drinking water sources not economically feasible to treat.
Corrective Action: The City will continue to implement chloride best management practices such as reducing salt use on roadways, education to private business
owners about correct salt application, and improve policies designating salt usage.
The City will continue to track and implement ways to reduce road salt usage
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based on its MPCA Level 1 and 2 Smart Salt Certifications.
5. Issue: Prioritizing inspection and maintenance of stormwater ponds as well as
determining the performance of existing stormwater ponds throughout the City.
Corrective Action: The City of Prior Lake will prioritize pond maintenance
activities and BMP inspections. This program will need to be updated regularly to result in an updated prioritization of pond inspection and maintenance activities. In
addition, the program will estimate the current treatment provided by each pond to determine if the desired amount of treatment is being achieved. This program will help meet the MS4 permit requirements related to the management of stormwater
ponds. I. Availability and Adequacy of Existing Technical Information to Manage Local
Water Resources
1. Issue: Atlas 14 (updated precipitation probability information) was recently released by NOAA.
Corrective Action: The City will continue to implement Atlas 14 in the review and
approval of new or redevelopment projects. The City will coordinate with the
watersheds, FEMA and the DNR on implementing Atlas 14 into its floodplain management and other applicable regulations.
2. Issue: The City has mapped the majority of its storm sewer system. As new and
redevelopment projects are completed, the storm sewer GIS database needs to continually be updated.
Corrective Action: The City will annually update its storm sewer GIS database to incorporate recent projects, BMPs, and associated storm sewer improvements.
3. Issue: The PLSLWD maintains Hydrologic and Hydraulic models for waterbodies within the City. Corrective Action: The City will annually provide routine updates to PLSLWD per new development, redevelopment, and any substantive stormwater management
improvements implemented.
7.6 GOALS AND POLICIES
A. Purpose
Prior Lake’s Local Surface Water Management Plan (LSWMP) aids with planning for the orderly management of stormwater as development occurs in the city. The plan provides clear guidance on how Prior Lake intends to manage surface water in terms
of both quantity and quality.
Much has changed since the city prepared its first LSWMP in 1973. Since that time,
the city has seen a marked increase in residential and commercial development. Not accounting for population growth due to annexation, city population has increased
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from almost 16,000 in 2000 to 25,049 in 2015; a growth of approximately 57%.
Population growth combined with increased regulation of stormwater at both the state and federal level necessitate that the city’s stormwater management goals evolve.
B. 2040 Vision and Strategic Plan
The original 2020 vision effort began in 2002 and since that time has included input
from numerous stakeholders in the community. The 2040 Vision and Strategic Plan focuses on preserving surface water and other natural resources, economic vitality,
and an overall safe and healthy community. The Prior Lake LSWMP is a piece of a
larger effort, conducted in partnership with the City’s two watershed organizations, toward addressing the 2040 vision of natural resources preservation.
The key issues facing the City constitute its vision statements. The elements of that vision become the City’s implementation goals out into the future. The 2040 vision
includes goals in a variety of areas. Of specific importance in the context of the
LSWMP are the following:
1. Community Assets
• Continue City commitment to on-going infrastructure maintenance and
replacement.
2. Natural Resources
• Update the Surface Water Management Ordinance in accordance with the City’s MS4 permit.
• Work with stakeholders to prepare and implement a plan which will address flooding issues and surface water matters.
• Work with local agencies to implement items listed in TMDL implementation
plans
C. Comprehensive Plan 2040 Goals and Policies
The Prior Lake 2040 Comprehensive Plan is currently being updated and will be
adopted in 2018. The primary purpose of this effort is determination of the land use plan (included in the LSWMP as Appendix A - Figure 7.2) which becomes the basis of
the hydrologic calculations summarized in the LSMWP. These Comprehensive Plans
are mandated by the Metropolitan Land Planning Act.
The goals of the Prior Lake 2040 Comprehensive Plan are:
• Housing Quality and Diversity
• Environmental and Natural Resource Protection
• Economic Vitality
• Security
• Access
• Information and Technology
• Human Development
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This Prior Lake LSWMP expands upon the goals and objectives provided in the 2040
vision and the 2040 Comprehensive Plan related to water resources management and protection.
D. City of Prior Lake LSWMP Goals and Policies
This section of the LSWMP outlines goals and policies specific to surface water management in Prior Lake. The policies that follow individual goals are specific requirements that promote attainment of the goal.
Water Quantity
Goal 1: To identify, plan and implement means to control runoff rate and volume.
Policy 1.1: Stormwater volume management, when required, shall meet the standards of the
Public Works Design Manual (PWDM).
Policy 1.2:
Preserve and optimize where feasible the retention capacities of the existing drainage systems by utilizing lakes, ponds, and wetlands for storing stormwater runoff.
Policy 1.3: Establish 100-year flood levels based on critical storm events using Atlas 14 rainfall data.
Policy 1.4: All minor storm sewer system design and analyses shall be based on the 10-year
Atlas 14 rainfall event consistent with the standards of this plan and the City’s PWDM.
Policy 1.5:
Stormwater best management practices (BMPs) shall be designed for the 100-year Atlas 14 rainfall event, consistent with the standards of this plan and the City’s PWDM.
Policy 1.6: Landlocked basins shall be analyzed and managed consistent with the standards of
the PWDM. Policy 1.7:
All hydrologic studies and drainage design shall be based on ultimate development of the 2040 land use plan. In some cases, near term conditions should also be analyzed to determine whether unrestricted drainage from rural areas may lead to construction
of interim facilities, or management based upon interim high-water levels or discharge rates.
Policy 1.8: In order to mitigate future development flows from increasing erosion potential to the
PLOC, the proposed discharge rates will be held to rates agreed to in the MOA. A
copy of the current PLOC MOA can be found in Appendix I of this Plan.
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Policy 1.9: All developments shall, to an extent determined by the City, provide land, funding, or a combination of both for developing regional detention sites to achieve the runoff rates
as indicated in this plan.
Policy 1.10:
Implement volume control and encourage low impact development techniques in developing and redeveloping areas to minimize runoff volumes that tend to increase
with an increase in impervious area.
Policy 1.11
Regional detention basins are used to manage peak flow rates and provide flood
storage and flood retention. On-site detention basins are utilized when regional basins are not in place or are not feasible. The city encourages the use of regional versus on-
site basins for rate control and flood protection.
Policy 1.12
Promote the use of overland versus pipe conveyance so that the benefits of natural channels can be realized. These benefits include filtration, flow attenuation, infiltration, and other water quality and quantity benefits. The city encourages the use of natural
vegetation within overland conveyance systems.
Policy 1.13:
Support the implementation of the prioritized policies per the Prior Lake Stormwater Management and Flood Mitigation Study (2016). These polices are listed below:
a. Protection of public safety and maintain emergency access at all times;
b. Protection of health and safety by protecting public utility infrastructure;
c. Maintain traffic flow through the County Road 21 corridor; and
d. Maintain access to private properties
Policy 1.14: Implement the short- and long-term feasible options to address flooding identified in
the Flood Mitigation Study.
Water Quality
Goal 2: To identify, plan, and implement means to effectively protect and improve water
quality.
Policy 2.1:
The City will work with partner agencies to implement TMDLs for impaired water bodies in the City and that receive drainage from the City.
Policy 2.2 Require water quality treatment for new construction, reconstruction, and other
projects based on the PWDM standards.
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2040 Comprehensive Plan Page 189
Policy 2.3:
Construct, where practicably feasible, best management practices (BMPs) to serve not only new development, but also existing development where opportunities arise to treat those areas that were established prior to stormwater management criteria
summarized in the PWDM.
Policy 2.4:
Implement a stormwater pollution prevention program (SWPPP) that meets or exceeds the requirements of the City’s MS4 permit.
Policy 2.5: Continue to partner with the WD and WMO to implement stormwater management
improvements, even when not required by local or state regulations.
Policy 2.6:
Continue to be proactive on salt usage by implementing the Winter Maintenance
Policy, incorporating chloride BMPs listed in the TCMA Chloride Management Plan, and providing staff training on salt usage and its impacts on water quality.
Policy 2.7 Assess existing stormwater management facilities for potential water quality
enhancements when planning MS4 maintenance
Policy 2.8
Identify partnership opportunities to implement water quality improvement practices that exceed minimum local or state requirements.
Water Resources Recreation
Goal 3
To protect and enhance water recreational facilities.
Policy 3.1
The City of Prior Lake will work with and support to the maximum extent practical the efforts of Minnesota Department of Natural Resources, the Corps of Engineers, the
United States Environmental Protection Agency, and other appropriate agencies in
promoting public enjoyment and recreational resource values.
Policy 3.2 Activities related to recreation, parks, open space, and trails systems shall be consistent with the City’s 2040 Comprehensive Plan and City Ordinances.
Fish and Wildlife Habitat
Goal 4: To protect and enhance fish and wildlife habitat.
Policy 4.1: To the greatest possible extent, natural areas shall be preserved, especially when
adjacent to wetland areas.
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Policy 4.2: Buffer zones of natural vegetation shall be maintained around lakes, ponds and wetlands as much as possible.
Policy 4.3:
Coordinate with the Department of Natural Resources (DNR) and the U.S. Fish and
Wildlife Service to protect rare and endangered species.
Policy 4.4:
Explore with the DNR, Prior Lake-Spring Lake Watershed District, and Scott WMO new methods of eradicating or controlling aquatic and terrestrial invasive species.
Policy 4.5: The City will work to create wildlife corridors throughout the City, where feasible.
Policy 4.6: The City will coordinate with local and state agencies to protect threatened and
endangered plant and animal species.
Groundwater
Goal 5: To promote groundwater protection and recharge.
Policy 5.1:
Implement the City’s approved Wellhead Protection Plan (Appendix G). Specific
policies include: • Promote proper management and sealing of wells.
• Continue to identify potential contaminant sources.
• Educate the public with the Annual Water Quality Report and other information through the City website.
• Collect data and promote data sharing among agencies. Policy 5.2:
Collaborate as necessary with various agencies to perform special studies related to
groundwater protection and recharge. The City will also work with the agencies to fill gaps in assessments of groundwater data.
Policy 5.3: Provide a permanent ponding volume below the outlet or overflow in ponds and
wetlands to promote groundwater recharge.
Policy 5.4:
Maximize infiltration with the use of BMPs whenever possible, in open areas within all proposed developments following MS4 requirements and the Minnesota Stormwater
Manual guidelines.
Policy 5.5:
Cooperate with state and regional agencies on groundwater monitoring, inventorying
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or permitting programs. These agencies could include the MPCA, MDH, DNR, Scott
WMO and PLSLWD. The City’s groundwater protection policies are intended to preserve groundwater levels and flow and protection of drinking water supplies.
Policy 5.6: Cooperate with the Department of Health and Scott WMO to ensure that all unsealed
or improperly abandoned wells within the City are properly sealed. Technical
requirements for the abandonment of these wells will be in conformance with the local and State regulations.
Wetlands
Goal 6:
To protect and preserve wetlands through administration of the Wetland Conservation Act.
Policy 6.1 Act as the local government unit responsible for enforcing the Wetland Conservation
Act of 1991. Policy 6.2
Discourage wetland disturbance. Wetlands must not be drained or filled, wholly or partially, unless replaced by restoring or creating wetland areas of at equal public value, as permitted by the Wetland Conservation Act.
Policy 6.3
Restrict clearing and grading within proximity of the wetland boundary to provide for a
protective buffer strip of natural vegetation to promote infiltration of sediment and nutrients. If grading occurs close to the wetland boundary native plant materials shall
be reestablished as a buffer strip per PWDM requirements.
Policy 6.4
Establish for City use a wetland bank account to allow for wetland debits and credits for city projects.
Policy 6.5 Require that a wetland delineation be prepared for any project that potentially includes a wetland.
Erosion and Sediment Control
Goal 7: To prevent soil erosion and sediment discharge into surface water systems through
enforcement of the City’s MS4 SWPPP and NPDES Construction permit.
Policy 7.1: Erosion and sediment control plans shall be required per the PWDM.
Policy 7.2:
The City may prohibit work in areas having steep slopes and high erosion potential.
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The provisions of the shoreland ordinance should be followed to prevent impact to
these erosion sensitive areas. Policy 7.3:
The City shall maintain a street sweeping program to minimize sediment entering the MS4. Streets will be swept according to the City’s street sweeping policy. The City’s
Street Sweeping Policy can be found in Appendix H of this Plan.
Policy 7.4
The City will periodically review ordinances related to erosion and sediment control
and drainage to maintain conformance with the NPDES construction permit, the City's MS4 permit, guidance from Metropolitan Council, and the requirements of the
regulating watersheds.
Prior Lake’s MS4 Permit
Goal 8: To operate and manage the City’s surface water system consistent with best current
practices and the City’s MS4 SWPPP.
Policy 8.1:
Projects to correct existing deficiencies, to the extent they are identified, will be prioritized as follows:
• Projects intended to reduce or eliminate flooding of structures in known problem areas
• Projects intended to improve water quality in the City’s lakes
• Projects intended to reduce maintenance costs
• Projects intended to restore wetlands and habitat
Policy 8.2:
The City will actively inspect, and properly operate, maintain and repair its public
stormwater facilities per MS4 permit requirements. The City will follow a regular inspection, cleaning, and repair schedule. Frequency of maintenance will be event-
based and informed by experience and inspection history. Policy 8.3:
The City will follow best management practices on its own lands and for its own projects including street reconstruction projects – in accordance with the City’s MS4 SWPPP.
Policy 8.4
Assess all existing stormwater management facilities for retrofit opportunities to
enhance water quality treatment during scheduled MS4 maintenance.
Policy 8.5
The City will implement a program that identifies and prioritizes pond maintenance activities and BMP inspections. This program will need to be updated regularly to
result in an updated prioritization of pond inspection and maintenance activities.
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Policy 8.6:
Operation and maintenance agreements shall be developed as part of all private BMPs. This agreement must include inspection schedules, procedures for maintenance and must meet any requirements outlined in the PWDM and the
Minnesota Stormwater Manual.
Financial Management
Goal 9:
To ensure that the costs of the surface water system are equitably distributed and to
utilize available funding mechanisms to construct and maintain a sustainable stormwater management system.
Policy 9.1: The City will continue to update and apply area-based charges so that the surface
water related costs of development can be fairly borne by the development.
Policy 9.2:
The City will periodically update its storm water utility rate structure to accomplish the following:
• Meet the requirements of its MS4 SWPPP.
• Provide for the maintenance and repair of stormwater infrastructure.
• Support its system planning efforts.
• Implement water quality improvement projects identified in the CIP.
Policy 9.3:
The City will utilize various funding sources including, but not limited to, PLSLWD,
Scott WMO, cost sharing and grants, area charges, stormwater utility, and other grants to accomplish improvements listed in this plan and other surface water
documents.
G. Impacts of the Prior Lake LSWMP on Other Units of Government
Other units of government with surface water-related jurisdiction within the City of Prior Lake include the Minnesota Pollution Control Agency (MPCA), Minnesota
Department of Natural Resources (DNR), United States Army Corps of Engineers (USACOE), the Shakopee Mdewakanton Sioux Community (SMSC), the Prior Lake-
Spring Lake Watershed District (PLSLWD), and the Scott Water Management
Organization (Scott WMO). The MPCA has jurisdiction over stormwater discharges to waters of the state of
Minnesota. The City will meet MPCA’s Municipal Separate Storm Sewer (MS4) permit and Construction Stormwater General Permit (MNR100001) requirements as outlined
within in this Plan.
The DNR has jurisdiction over public waters and public waters wetlands as defined in
Minnesota Statute 103G. The City will follow all DNR requirements with respect to
public waters and public waters wetlands when sponsoring or permitting projects that could impact these resources.
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 194
The USACOE is the federal agency that regulates discharges of dredged or fill
material into waters of the United States (wetlands, tributaries, lakes, etc.) under Section 404 of the Clean Water Act (CWA) and regulates work in navigable waters under Section 10 of the Rivers and Harbors Act. The City will ensure that USACOE
regulations are followed when sponsoring or permitting projects that fall under USACOE jurisdiction.
The Shakopee Mdewakanton Sioux Community (SMSC) is a federally recognized sovereign nation located partially within the boundaries of the City of Prior Lake. The
SMSC has jurisdiction over water resources on lands placed in trust for the SMSC by
the Department of the Interior. Areas of the SMSC that do not have trust status are subject to City jurisdiction. The City works closely with the SMSC to manage our water
resources within our common boundaries.
Two watershed management organizations have jurisdiction within the City: The Scott
WMO and the PLSLWD. Both watersheds must review and approve the LSWMP. The
City envisions its two watersheds as partners in implementing this Plan. Because the City must meet water quality regulations and standards through the state-mandated
MS4 and Construction Stormwater General permits, much of the City’s available stormwater budget will be used meeting these regulations and standards and maintaining existing MS4 infrastructure. Therefore, the City envisions the watersheds
taking the lead on water quality monitoring, voluntary water quality projects, enhancing the water quality improvement aspects of City-led maintenance projects, and other
water quality initiatives in accordance with their Watershed Management Plans.
The City will work closely with the PLSLWD to implement projects and initiatives
called out in the Prior Lake Stormwater Management and Flood Mitigation Study
(2016). Although most flood retention storage will likely be located outside the existing City boundary, the City will provide support for these projects as warranted by each
specific project.
The City and PLSLWD entered into a Memorandum of Agreement (MOA) for local
water planning and regulation in 2007. The MOA specified the responsibilities of the PLSLWD and the City for issuing permits affecting water resources within the City. The City assumed all permitting powers within its jurisdiction after the MOA was
signed by both organizations, with the exception of its own projects. The MOA terminated automatically when the PLSLWD adopted a revised Water Resources Management Plan (WRMP) in 2010 and the MOA was not extended by written
agreement of both parties (Section 4.4, 2007 MOA). The MOA stated that the City’s implementation plan for local water management was in conformance with PLSLWD’s
WRMP. Although the MOA technically expired, the City and PLSLWD rules have not
been substantively changed since 2007 and should still be considered equivalent. The City intends to enter a new permitting MOA with the PLSLWD. The new MOA should
be based on existing rules and updated after completion of the PLSLWD’s next
WRMP and/or rules updates. This may require an additional process to evaluate rules equivalency and possibly an amendment to the City’s LSWMP.
The City and Scott WMO have substantially equivalent rules. The City maintains permitting authority within the Scott WMO, with Scott WMO retaining the right to audit
project reviews that occur within its jurisdiction. The Scott WMO portion of the City’s
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2040 Comprehensive Plan Page 195
current and 2040 boundary drains toward the City of Shakopee and the Credit River.
The flows and routes that discharge from Prior Lake into Shakopee were developed in consultation with the City of Shakopee and in conjunction with their surface water planning efforts. Further coordination will be needed to address the concerns of the
WMO when areas within the upper reaches of the WMO are proposed for development.
H. Watershed Goals and Strategies that Affect the City of Prior Lake
PLSLWD The City of Prior Lake, PLSLWD, and Spring Lake Township jointly developed goals
related to volume management that will have a profound effect on the City as it implements its surface water system. Specifically, the Prior Lake Stormwater
Management and Flood Mitigation Study (2016) calls for retention storage to mitigate
the impact of future development on Prior Lake and its outlet channel. The City will work closely with the PLSLWD to implement practices outlined in the Flood Study’s Implementation Plan. PLSLWD will assume the lead role for all practices located
outside the City; the City will provide support for those practices.
The City will work with PLSLWD Spring Lake Township to periodically review the
Flood Study Implementation Plan, evaluate progress, and update as needed.
Scott WMO
The City’s 2040 boundary includes areas in the Scott WMO that may merit additional protections based on past water quality improvement projects and downstream
impairments. These include the Picha Creek watershed and areas draining to
Campbell Lake, and ultimately to Sand Creek and the Minnesota River. The City will work with Scott WMO to determine the adequacy of on-site and/or regional
stormwater management facilities in these areas. 7.7 IMPLEMENTATION PROGRAM
A. Overview
The Implementation Plan section of the Prior Lake LSWMP describes a range of
activities and programs that support improvement of the City’s surface water management program. Capital outlay for the surface water system (pipes, channels,
and ponds) shown on the system maps will be large. For this reason, a City financing
mechanism, called an area charge, is reviewed in this section. Based on the Capital Improvement Plan and the developable acreage, the City’s current area charge is
reviewed, and application of this charge is discussed.
The concept of an area charge to finance expansion of the trunk stormwater management system is not a new concept for the City. Since its report titled Trunk
Storm Sewer Fee Determination Study (February 2001) the City has quantified future
trunk and ponding needs and developed an area charge based on actual costs of
these needs spread across the potential developable acreage. With the analysis
contained within the LSWMP the City will update the fees for the 2040 growth area.
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Much of this section of Prior Lake’s LSWMP focuses on the analysis that supports the
development of the area charge. There are also several City planning and budgeting
documents that outline surface water management activities undertaken by the City.
Those documents are identified in Table 7.13 and are incorporated by reference into
this Plan.
Table 7.13 Planning and Budgeting Documents
Plan/Document Revision Frequency/Notes
Capital Improvement Program Annually
City Budget Documents Annually
Stormwater Pollution Prevention Program Every five years (minimum)
B. Review of the Existing Trunk Stormwater Acreage Charge In 2018, the City completed a review of their Trunk Stormwater Acreage Charge. The
original fee has not changed significantly from 2001-2016. The City performed a review of the construction cost index (CCI) from 2005-2016 and identified there has
been a 36% increase in construction costs over this period. A decision from the City
Council directed staff to phase the CCI increase over several years. The incremental increase recommended was 10% over the years of 2016-2019. A copy of the
complete memo can be found in Appendix K.
C. Operation and Maintenance
1. Activities
A stormwater system is a major investment for the City of Prior Lake – both in
terms of initial capital cost and in terms of ongoing maintenance costs. The capital improvement program outlines the costs for new trunk system construction which
will be funded by area charges. System maintenance is funded by the city’s stormwater utility.
The city’s stormwater system maintenance responsibilities include the following: • Stormwater basins
• Cleaning of sump manholes and catch basins • Inspection and repair of storm sewer inlet structures • Open channels
• Assessing pipe condition (typically by televising) • De-icing practices
• Street sweeping
A brief description of each of these practices is listed below.
2. Stormwater Basins
Stormwater basins represent a sizable investment in the City's drainage system. General maintenance of these facilities helps ensure proper performance and
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reduces the need for major repairs. Periodic inspections are performed to identify
possible problems in and around the basin. Inspection and maintenance cover the following:
• Basin outlets/inlets
• Side slopes
• Illicit dumping and discharges
• Sediment buildup
A key issue with stormwater basins is ensuring that the outlets perform at design
capacity and that the outlet is kept clear of debris and vegetation. Inlets are inspected for erosion and excess sediment deposits. Side slopes are to be kept well-vegetated to prevent erosion and sediment deposition into the basin and are
inspected for noxious weeds. Basins are periodically inspected for evidence of illicit dumping or discharges. The most common of these is dumping of yard waste
into the basin. Sediment removal is performed where excessive sediment buildup
has occurred. Table 7.14 provides a typical maintenance schedule for wet ponds.
Table 7.14 Stormwater Pond Maintenance Schedule
Repair undercut or eroded areas. As needed
Remove sediment accumulated sediment in the forebay
and permanent pool
2 to 7 years or when
50% of capacity has
been lost
Adapted from the Minnesota Stormwater Manual: Operation and Maintenance of Stormwater Ponds
3. Sump Manholes and Sump Catch Basins
Sump manholes and sump catch basins are included in storm sewer systems to
collect sediments before they are transported to downstream water bodies. These structures keep sediments from degrading downstream water bodies. Once
sediments are transported to a lake or pond, they become much more expensive
to remove.
Construction activity and erosion are the main contributors of sediment into the
stormwater system. Since these structures are designed to collect these sediments, they are routinely inspected and cleaned to provide capacity for future
sedimentation. Suction vacuum equipment is typically used.
Activity Schedule
Inspect regional pond outlets for clogging. After significant rainfalls
Inspect for damage.
Note signs of hydrocarbon build up. Monitor for sediment accumulation in the facility and
forebay. Examine to ensure that inlet and outlet devices are free of debris and operational.
Annual inspection
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4. Storm Sewer Inlet Structures
To fully utilize storm sewer capacity, inlet structures are kept operational in order to transport stormwater runoff into the system. All efforts are made to keep catch
basins and inlet flared ends free of debris and sediments so as not to restrict inflow and cause flood damage. Leaf and lawn litter are the most frequent cause
of inlet obstructions. On a routine basis, City staff visually inspects inlet structures
to ensure they are operational.
5. Open Channels
Overland flow routes constitute an important part of the surface water drainage
system. Open channels are typically vegetated and occasionally lined with more
substantial materials. The lined channels typically require little or no maintenance. Vegetated channels are periodically inspected and maintained, as high flows may
create erosion within the channel.
Eroded channels can contribute to water quality problems in downstream water
bodies as the soil is continually swept away. If not maintained, the erosion of open channels would accelerate, and the repair would become increasingly more costly. The use of bioengineering and natural stream technology, which mimics the
characteristics of natural streams to promote channel stability, can reduce the potential for erosion.
6. Piping System
The storm sewer piping system constitutes a multimillion-dollar investment for the
City. The City performs a comprehensive maintenance program to maximize the life of the facilities and optimize capital expenditures. The following periodic
inspection and maintenance procedures are followed:
• Catch basin and manhole castings are inspected and are cleaned and
replaced as necessary.
• Catch basin and manhole rings are inspected and are replaced and/or
regrouted as necessary.
• Catch basin and manhole structures are inspected and are repaired or replaced as needed. Pipe inverts, benches, steps (verifying integrity for
safety), and walls are checked. Cracked, deteriorated, and spalled areas are grouted, patched, or replaced.
• Storm sewer piping is inspected either manually or by television to assess pipe condition. Items looked for include root damage, deteriorated joints,
leaky joints, excessive spalling, and sediment buildup. The piping system is
programmed for cleaning, repair, or replacement as needed to ensure the integrity of the system.
7. De-Icing Practices
Minnesota receives approximately 54 inches of snow during a typical year. This
requires a large amount of de-icing chemicals (primarily salt) to be applied to roads and sidewalks each winter. Improper storage as well as overuse of salt
increases the risk of high chloride concentrations in runoff and groundwater. High
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2040 Comprehensive Plan Page 199
chloride concentrations can be toxic to fish, wildlife, and vegetation.
The following procedures are used for storing de-icing chemicals in the City.
• De-icing material is stored in waterproof sheds. Where this is not possible,
stockpiles are covered with polyethylene and placed on impervious surfaces.
• Road de-icing stockpiles are not located near municipal well areas or in other
sensitive groundwater areas.
• Runoff from stockpiles is not allowed to flow directly into streams or wetlands
where environmental damage can occur.
Prior Lake has established a detailed Winter Maintenance Policy to address winter
maintenance needs. Street conditions are assessed for each individual event and ice control material application is adjusted accordingly. Equipment is maintained in
good working order to place ice control material on roadways and is properly
calibrated to prevent excessive application.
8. Street Sweeping
Street sweeping is an integral part of the City’s effective surface water
management system. It greatly reduces the volume of sediments that have to be cleaned out of sump structures and downstream water bodies. The City has a “street sweeping policy” that includes one sweeping of the entire city in the spring
and additional sweepings around targeted areas throughout the remainder of the year. Sweeping priorities for targeted areas in order are the following: TMDL
drainage areas, non-TMDL direct drainage areas for nonimpaired lakes, drainage
areas with existing stormwater treatment systems that drain to surface waters, and landlocked areas. Spring sweeping begins either late March or early April after the
risk of later snowfall has passed and targets sand left from winter sanding
operations.
Prior Lake does not allow residents to rake leaves into the street for pick up but
does provide a compost site where residents can bring their leaves. This greatly reduces the incidence of inlet blockages and protects the water quality of
downstream water bodies. The objective of both programs is to minimize impacts from leaf litter, salt and other debris on the surface waters of the City.
D. Education
In order to obtain the necessary political and economic support for successful LSWMP implementation, it is vital to inform City residents about basic stormwater management
and water quality concepts, policies and recommendations in the LSWMP, and the
progress of stormwater management efforts. Education is also required as part of the MS4 Permit.
This information is presented to the public through the City newsletter, press releases on the City website or to local papers, through the Mayor’s and City Manager’s
columns, and at public meetings as appropriate. Periodic updates on the progress of LSWMP implementation and information on specific improvement projects is also provided to the public.
City of Prior Lake Surface Water Management
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E. Financing and Stormwater Utility The City of Prior Lake implemented a stormwater utility in 1993. The current quarterly
residential charge is $14.34 per residential unit. As the city’s maintenance responsibilities grow, the stormwater utility funding also needs to grow to keep pace.
The NPDES permit and SWPPP commit the city to certain activities, including capital
projects, for the purpose of improving the quality of the city’s stormwater discharge. Prior Lake’s capital improvement projects and MS4 permit requirements are listed in
Table 7.15.
The City will use funds generated from its stormwater utility as the primary funding
mechanism for its implementation program including; maintenance, repairs, capital
projects, studies, etc. If funds from this utility fee do not cover necessary costs, the City will consider adjusting the stormwater utility fee to cover the costs associated with
the implementation program. The City will continue to review the stormwater utility fee
annually and adjust based on the stormwater related needs of the City and other available funding mechanisms. The City will also take advantage of grant or loan
programs to offset project costs where appropriate and cost-effective. Below is a list of various sources of revenue that the City will attempt to utilize:
• Grant monies possibly secured from various agencies. This could include
PLSLWD, Scott WMO, Scott County, Mn/DOT, the MPCA, the DNR, Legislative-Citizen Commission on Minnesota Resources (LCCMR), the Board
of Water and Soil Resources (BWSR), Metropolitan Council and others.
• Special assessments for local improvements performed under authority of Minnesota Statutes Chapter 429.
• Developer funds.
• Other sources potentially including tax increment financing, tax abatement, state aid, and others.
F. Design Standards
The City of Prior Lake has produced and regularly updates the Public Works Design
Manual. The latest version of this manual is titled Public Works Design Manual, City of Prior Lake, July 2007. This manual, as revised, is adopted by reference into City
ordinance and into this Surface Water Management Plan as the applicable design
standard for surface water management.
G. Watershed Implementation Priorities
The Prior Lake-Spring Lake Watershed District has adopted a Water Resources
Management Plan that includes programs and projects focused on water quality and runoff management, land management to improve water quality and reduce runoff volumes, and management of the Prior Lake Outlet System. As part of the PLSLWD
Water Resources Management Plan, a detailed list of implementation priorities has been developed for partnership opportunities between the City and watershed district.
The Scott WMO will adopt a revised Water Resource Management Plan at the end of 2018. This Plan focuses on select priorities and major issues identified through input
from various agencies and presents goals and policies to help implement solutions for
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2040 Comprehensive Plan Page 201
these issues. The Scott WMO implementation priorities specifically for the City of Prior
Lake include two assessments related to Campbell Lake and the DRSMA, deicing and street sweeping practices and priorities, and addressing water-related CIPs in this LSWMP.
H. City of Prior Lake Implementation Priorities
Projects listed in Table 7.15 to correct existing deficiencies, to the extent they are identified, will be prioritized as follows:
• Projects intended to reduce or eliminate flooding of structures in known
problem areas
• Projects intended to improve water quality in the City’s lakes
• Projects intended to reduce maintenance costs
• Projects intended to restore wetlands and habitat
Other implementation priorities for the City as it adopts this Plan and begins the implementation phase of the Plan include:
• Implement the City’s MS4 SWPPP.
• Partner with PLSLWD to implement options listed in the Prior Lake Stormwater
Management & Flood Mitigation Study.
• Ensure the Stormwater Utility Funding is adequate to maintain the existing
stormwater system and to meet its current and future obligations toward pond
maintenance and MS4 compliance.
• Application of the revised area charge outlined in this report and update of the
area charge based on increases in land value and construction costs.
• Implementation of the rate control targets as outlined in the appendices and
stormwater modeling that supports this plan.
• Application of the wetland susceptibility criteria in determining how wetlands are
used for flood storage, retention, and rate control.
• Maintaining equivalency with Scott WMO and PLSLWD rules.
• Working in partnership with WMO and WD to minimize downstream impacts.
Specific implementation items for the City are listed in Table 7.15.
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2040 Comprehensive Plan Page 202
TABLE 7.15
SURFACE WATER MANAGEMENT IMPLEMENTATION PLAN
10 Year Total
Possible Proposed Cost by Year1
No. Project Description Cost Estimate
1,3
Watershed
District4 Funding
Sources 2
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
Comments
Capital Improvement Projects (CIP)
1
General stormwater improvements - Placeholder for
stormwater projects listed in the City's CIP.
$250,000
City-Wide
Stormwater Fee,
Scott WMO,
PLSLWD,
Grants
$25,000
$25,000
$25,000
$25,000
$25,000
$25,000
$25,000
$25,000
$25,000
$25,000
City's CIP
2
PLSLWD Storage and Infiltration Projects - Continue to
partner with the PLSLWD on projects to reduce runoff,
increase infiltration, and reduce pollutant loading and
transport to Spring and Upper Prior Lakes.
$450,000
PLSLWD Stormwater Fee,
PLSLWD,
Grants
$50,000
$50,000
$50,000
$50,000
$50,000
$50,000
$50,000
$50,000
$50,000
Spring and Upper Prior Lake
TMDL Implementation Plan
3
Wetland Restoration - Continue to partner with PLSLWD on
projects to restore key wetland to increase storage, improve
habitat, and create a wetland bank to mitigate future wetland
loss from development.
$250,000
PLSLWD Stormwater Fee,
PLSLWD,
Grants
$50,000
$50,000
$50,000
$50,000
$50,000
Spring and Upper Prior Lake
TMDL Implementation Plan
4
PLSLWD Public Infrastructure Partner Projects - Continue to
partner with PLSLWD to retrofit streets,
highways, and other public infrastructure with volume
management and load reduction BMPs on routine street,
highway, and other reconstruction projects. Upcoming
projects could include Balsam, Sunrise, and Manitou.
$675,000
PLSLWD
Stormwater Fee,
PLSLWD,
Grants
$75,000
$75,000
$75,000
$75,000
$75,000
$75,000
$75,000
$75,000
$75,000
PLSLWD Watershed
Management Plan
Implementation Items
5
Jeffers Pass Outlet Improvement - Install a grate or barrier to
prevent the build-up of debris placed by beavers.
$20,000
PLSLWD
Stormwater Fee,
Grants
$20,000
Issue 5.3.1
6
Island View Culvert Replacement - The City will upgrade the
structure and coordinate with the PLSLWD and DNR as
needed.
$20,000
PLSLWD Stormwater Fee,
PLSLWD,
Grants
$20,000
Issue 5.3.2
7
Glynwater Trail NW Culvert Replacement - An outlet
improvement project will be completed to provide an
improved overflow structure and resizing of the culvert.
$30,000
PLSLWD
Stormwater Fee,
PLSLWD,
Grants
$30,000
Issue 5.3.3
8
Wildwood Pond Outlet - An outlet improvement project will be
completed to provide an overflow structure with an improved
skimmer.
$30,000
PLSLWD Stormwater Fee,
PLSLWD,
Grants
$30,000
Issue 5.3.4
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 203
10 Year Total
Possible Proposed Cost by Year1
No. Project Description Cost Estimate
1,3
Watershed
District4 Funding
Sources 2
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
Comments
9
Northwood Road Wetland Outlet - An outlet improvement
project will be completed to provide an overflow structure with
an improved skimmer that will better maintain the water level.
This work may also include a carp grate installed in
cooperation with the PLSLWD.
$40,000
PLSLWD
Stormwater Fee,
PLSLWD,
Grants
$40,000
Issue 5.3.7
10
Adelmann Street Pond - The pond located near County Road
21 and Adelmann Street currently has an outlet that is not
functioning properly. The City will complete a survey of the
pond and perform a pond cleanout project as necessary.
$153,000
Scott WMO
Stormwater Fee,
Scott WMO,
Grants
$3,000
$150,000
Issue 5.3.9
11
Crystal Lake Outlet Improvement - An outlet improvement
project will be completed to provide an overflow structure with
an improved skimmer that will better maintain the water level.
The outlet will also include measures to prevent beavers from
blocking the outlet.
$20,000
PLSLWD
Stormwater Fee,
PLSLWD,
Grants
$20,000
Issue 5.3.12
12
Deerfield Lane Pond Improvement - Survey and cleanout the
pond to remove sediment. Identify the need to remove the
outlet to the adjacent pond to provide additional storage.
$80,000
Scott WMO
Stormwater Fee,
Scott WMO,
Grants
$80,000
Issue 5.3.14
13
Markley Lake Erosion - There are significant erosion issues
on a City-owned parcel on the south side of Markley Lake.
The City will provide short term stabilization measures as
needed. The long-term goal for this area will be to stabilize an
eroding ravine and provide additional flood storage as well.
$280,000
Scott WMO
Stormwater Fee,
Scott WMO,
Grants
$15,000
$15,000
$250,000
Issue 5.5.2
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 204
10 Year Total
Possible Proposed Cost by Year1
No. Project Description Cost Estimate
1,3
Watershed
District4 Funding
Sources 2
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
Comments
MS4 Permit Items and Regular Maintenance
14
Education Activity - Complete education activity outlined in
the MS4 permit and SWPPP. Continue to partner with Scott
WMO and PLSLWD on education related items including
involvement in the Scott Clean Water Education Program,
demonstration projects, resident education, education
materials, etc.
$15,000
City-Wide
Stormwater Fee
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
Spring and Upper Prior Lake
TMDL Implementation Plan;
MS4 Permit
15
Annual SWPPP Assessment & Annual Reporting City staff
will conduct an annual SWPPP assessment in preparation of
each annual report. Proposed SWPPP modifications are
subject to Part II.G of the MS4 permit.
$10,000
City-Wide
Stormwater Fee
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
City's MS4 Permit And
SWPPP
16
Online Availability of the Stormwater Pollution Prevent Plan
(SWPPP) Program Document - The City will make the
SWPPP and each year's annual report available on the City's
webpage and will update as needed.
$2,000
City-Wide
Stormwater Fee
$200
$200
$200
$200
$200
$200
$200
$200
$200
$200
City's MS4 Permit And
SWPPP
17
Employee Training - Continue to host a minimum of one staff
training event per year to discuss illicit discharge recognition
and reporting. City staff will continue to develop an annual
training schedule, record the employee names, topics
covered, and date of each event.
$5,000
City-Wide
Stormwater Fee
$500
$500
$500
$500
$500
$500
$500
$500
$500
$500
City's MS4 Permit And
SWPPP
18
Establishment of Procedures for Site Inspections and
Enforcement - The City will inspect construction sites for
conformance to NPDES construction permit standards and
applicable City standards. This goal will be met by enforcing
the City's erosion control and waste disposal standards.
$50,000
City-Wide
Stormwater Fee
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
City's MS4 Permit And
SWPPP
19
Site Plan Review Program - The City will review and revise (if
necessary, during the plan review process) permanent BMP
designs and criteria for post-construction stormwater
management associated with new development and
redevelopment projects of one acre or more. The City will
also actively look for non-structural opportunities where prudent and feasible.
$30,000
City-Wide
Stormwater Fee
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
City's MS4 Permit And
SWPPP
20 Storm Sewer Mapping - The City will annually update its
storm sewer system map. $8,000 City-Wide Stormwater Fee $800 $800 $800 $800 $800 $800 $800 $800 $800 $800 City's MS4 Permit And
SWPPP
21
Street Sweeping - Conduct street sweeping operations per
the City's Street Sweeping Policy.
$200,000
City-Wide
Stormwater Fee
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
City's MS4 Permit And
SWPPP
22
Structural Stormwater BMP Inspections - Continue to inspect
100% of all structural stormwater BMPs each year as
required per the MS4 permit.
$80,000
City-Wide
Stormwater Fee
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
City's MS4 Permit And
SWPPP
23
Inspect MS4 Outfalls and Ponds - Continue to inspect 20% of
all MS4 outfalls each year, until 100% of all MS4 Outfalls and
Ponds have been inspected.
$80,000
City-Wide
Stormwater Fee
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
$8,000
City's MS4 Permit And
SWPPP
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 205
10 Year Total
Possible Proposed Cost by Year1
No. Project Description Cost Estimate
1,3
Watershed
District4 Funding
Sources 2
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
Comments
24
Review Inspection Reports - Annually, review all pond, outfall,
and SPCD inspection records to determine if maintenance,
repair, or replacement is needed. Include a description of the
findings and any maintenance, repair, or replacement as a
result of the inspection findings. Evaluate each structural
pollution control device (SPCD) inspection frequency and
adjust as needed per MS4 Permit Part III.D.6.e(1.).
$20,000
City-Wide
Stormwater Fee
$2,000
$2,000
$2,000
$2,000
$2,000
$2,000
$2,000
$2,000
$2,000
$2,000
City's MS4 Permit And
SWPPP
25
Stormwater Systems Maintenance Training Program -
Training focused on parking lot and street cleaning, storm
drain systems cleaning, road salt materials management.
$15,000
City-Wide
Stormwater Fee
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
$1,500
City's MS4 Permit And
SWPPP
26
Road Salt Application Review - The City will record the
annual activities of the salt distribution program and adjust
current practices as necessary.
$10,000
City-Wide
Stormwater Fee
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
$1,000
City's MS4 Permit And
SWPPP
27
Operation and Maintenance - Continue to perform and track
annual inspections of all public water quality BMPs. Track all
required maintenance and repairs required and completed.
$50,000
City-Wide
Stormwater Fee
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
$5,000
City's MS4 Permit And
SWPPP
28
Pond Surveys - The City will annually complete pond surveys
to schedule and prioritize the necessary maintenance projects.
$30,000
City-Wide
Stormwater Fee
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
$3,000
City's MS4 Permit And
SWPPP
29
Pond Maintenance and Retrofit - The City will annually
maintain stormwater ponds and enhance overall system
treatment efficiency.
$1,625,000
City-Wide
Stormwater Fee
$300,000
$25,000
$300,000
$25,000
$300,000
$25,000
$300,000
$25,000
$300,000
$25,000
City's MS4 Permit And
SWPPP
30
Chloride Management - The City will promote and adopt
strategies included in the TCMA Chloride Management Plan.
$50,000 City-Wide Stormwater Fee $5,000 $5,000 $5,000 $5,000 $5,000 $5,000 $5,000 $5,000 $5,000 $5,000
City's MS4 Permit And
SWPPP
31
Stormwater Infrastructure Maintenance - Maintenance,
retrofit, and creation of structural stormwater practices such
as sump manholes, bioretention, infiltration and filtration
$520,000
City-Wide
Stormwater Fee
$60,000
$60,000
$60,000
$60,000
$20,000
$60,000
$60,000
$60,000
$60,000
$20,000
City's MS4 Permit And
SWPPP
32
PLSLWD District-Wide Model Updates - Continue to
cooperate and data share as the District completes regular
updates of their XPSWMM models.
$5,000
City-Wide
Stormwater Fee
$500
$500
$500
$500
$500
$500
$500
$500
$500
$500
City's MS4 Permit And
SWPPP
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 206
10 Year Total
Possible Proposed Cost by Year1
No. Project Description Cost Estimate
1,3
Watershed
District4 Funding
Sources 2
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
Comments
Official Controls
33
Ordinance Updates - The City will continually review their
ordinances related to stormwater, erosion and sediment
control, wetlands, and floodplains for consistency with state
and watershed requirements.
$5,000
City-Wide
Stormwater Fee
$500
$500
$500
$500
$500
$500
$500
$500
$500
$500
34 Prioritize Inspections - The City will develop a process to
determine the frequency for inspecting high priority inspection
sites (e.g. near sensitive receiving waters).
$2,000
City-Wide
Stormwater Fee
$1,000
$1,000
35
Evaluate the Need to Update the Stormwater Utility Fee - The
City will review the implementation of proposed programs and
improvements identified in this plan and will determine the
potential update of the stormwater utility fee.
$5,000
City-Wide
Stormwater Fee
$1,000
$1,000
$1,000
$1,000
$1,000
36 Flood Response Policy - Review and update as needed the
City's Flood Response Policy and evaluate the effectiveness
of action items.
$8,000 City-Wide Stormwater Fee $800 $800 $800 $800 $800 $800 $800 $800 $800 $800
37
Winter Maintenance and Street Sweeping Policies - Review
and update as needed the City's Winter Maintenance Policy
and Street Sweeping Policy.
$8,000 City-Wide Stormwater Fee $800 $800 $800 $800 $800 $800 $800 $800 $800 $800
Monitor and Study
38
Campbell Lake Regional Stormwater Assessment - Additional
development is planned around Campbell Lake, which is the
headwaters for Picha Creek. Partner with Scott WMO to
complete a study that would assess potential issues with
development, and identify potential opportunities for regional
stormwater management.
$30,000
Scott WMO
Stormwater Fee,
Scott WMO,
Grants
$30,000
Scott WMO Watershed
Management Plan; Issue
5.6.5
39
City of Prior Lake DWSMA Abandoned Well Assessment -
Partner with Scott WMO to review the City's Drinking Water
Supply Management Area to develop a methodology for
identifying probable locations of abandoned/unsealed wells.
Results will also be used to target contacts for the well
sealing cost share practice implementation through the TACS
program.
$30,000
Scott WMO
Stormwater Fee,
Scott WMO,
Grants
$30,000
Scott WMO Watershed
Management Plan
40
Innovative Phosphorus Load Reductions Study - Complete
feasibility reports to identify areas suitable for new
management methods and innovative technologies for TP
load reductions.
$90,000
City-Wide
Stormwater Fee,
Watershed
Partnerships,
Grants
$30,000
$30,000
$30,000
Spring and Upper Prior Lake
TMDL Implementation Plan
41
BMP Research - Partner with local agencies to investigate or
contribute to research on the functionality of constructed
BMPs and/or innovative BMP options for stormwater
treatment.
$200,000
City-Wide
Stormwater Fee,
Watershed
Partnerships,
Grants
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
$20,000
Spring and Upper Prior Lake
TMDL Implementation Plan
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 207
10 Year Total
Possible Proposed Cost by Year1
No. Project Description Cost Estimate
1,3
Watershed
District4 Funding
Sources 2
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
Comments
42
Priorwood Street Pond - The City will complete a feasibility
study to determine a realignment of the channel is to the
pond possible.
$40,000
PLSLWD Stormwater Fee,
PLSLWD,
Grants
$40,000
Issue 5.3.5
43
Shady Beach Trail Ravine - The City will complete a feasibility
study to determine the best options for drainage mitigation.
$40,000
PLSLWD
Stormwater Fee,
PLSLWD,
Grants
$40,000
Issue 5.3.8
44
Priorwood Lane Pond Study - The City will complete a
feasibility study to analyze the existing pond system to
mitigate outlet issues and flooding.
$30,000
PLSLWD
Stormwater Fee,
PLSLWD,
Grants
$30,000
Issue 5.3.13
45
City-wide Stormwater Model - The City will create a
stormwater system model to identify problem areas and
needed system repairs/upgrades.
$85,000
City-Wide
Stormwater Fee,
Watershed
Partnerships,
Grants
$85,000
Issue 5.3.11
TOTAL $5,676,000 $534,100 $373,100 $675,100 $458,100 $652,100 $568,100 $750,100 $413,100 $919,100 $333,100
1 Cost estimates are preliminary and subject to review and revision as engineer's reports are completed and more information becomes available. Table reflects 2018 costs and does not account for inflation. Costs generally include labor, equipment, materials, and all other costs necessary to
complete each activity. Some of the costs outlined above may be included in other operational costs budgeted by the City.
2 Funding for stormwater program activities projected to come from following sources - Surface Water Management Fund, Developers Agreements, Grant Funds, General Operating Fund, or Special Assessments.
3 Staff time is not included in the cost shown.
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 208
7.8 ADMINISTRATION
A. Review and Adoption Process
Review and adoption of this Surface Water Management Plan will follow the
procedure outlined in Minnesota Statutes 103B.235:
‘After consideration but before adoption by the governing body, each local government unit shall submit its water management plan to the watershed management
organization[s] for review for consistency with the watershed plan. The organization[s] shall have 60 days to complete its review.’
‘Concurrently with its submission of its local water management plan to the watershed management organization, each local government unit shall submit its water
management plan to the Metropolitan Council for review and comment. The council
shall have 45 days to review and comment upon the local plan. The council’s 45-day review period shall run concurrently with the 60-day review period by the watershed
management organization. The Metropolitan Council shall submit its comments to the watershed management organization and shall send a copy of its comments to the local government unit.’
‘After approval of the local plan by the watershed management organization[s], the
local government unit shall adopt and implement its plan within 120 days and shall
amend its official controls accordingly within 180 days.’ B. Amendment Procedures The Prior Lake LSWMP is intended to extend through the year 2027. For the plan to
remain dynamic, an avenue must be available to implement new information, ideas,
methods, standards, management practices and any other changes that may affect the intent and/or results of the LSWMP. The amendment procedure for the LSWMP is
presented below.
1. Request for Amendment
Written request for plan amendment is submitted to City staff. The request shall outline the need for the amendment as well as additional materials that the City will need to consider before making its decision.
2. Staff review of Amendment
A decision is made as to the validity of the request. Three options exist: 1) reject
the amendment, 2) accept the amendment as a minor issue, with minor issues collectively added to the plan at a later date, or 3) accept the amendment as a major issue, with major issues requiring an immediate amendment. In acting on an
amendment request, City staff shall recommend to City Council whether or not a public hearing is warranted.
3. Council Consideration The amendment and the need for a public hearing shall be considered at a regular
or special Council meeting. Staff recommendations should also be considered
City of Prior Lake Surface Water Management
2040 Comprehensive Plan Page 209
before decisions on appropriate action(s) are made.
4. Public Hearing and Council This step allows for public input based on public interest. Council shall determine
when the public hearing should occur in the process. Based on the public hearing, the City Council could approve the amendment.
5. Council Adoption Final action on an amendment is City Council adoption. However, prior to the
adoption, an additional public hearing could be held to review the plan changes
and notify the appropriate stakeholders.
6. Coordination with WMO and WD
To the extent and manner required by the PLSLWD and Scott WMO, all major amendments to the LSWMP (including, but not limited to, substantive new data,
updated management practices, and rule revisions) shall be submitted to the
watersheds for review and approval in accordance with applicable state rules and statutes (Section 103B and Rules). For any minor updates, the City will coordinate
with the WMO and WD as any changes are made. Minor amendments, such as those completed for TMDLs, CIP updating, Nondegradation Planning, and Groundwater Protection, do not need to be submitted to the WD and WMO for
approval.