SURFACE WATER MANAGEMENT PLAN
For the
CITY OF SAINT PAUL PARK
Prepared by
McCombs Frank Roos Associates, Inc.
August 2009 I hereby certify that this plan, specification or report was prepared by me or under my direct supervision and that I am a duly Registered Professional Engineer under the laws of the State of Minnesota. Date Jeffrey J. Roos, P.E.,
Minnesota Registration No. 10206
CITY OF SAINT PAUL PARK
DRAFT SURFACE WATER MANAGEMENT PLAN
TABLE OF CONTENTS
SECTION I – EXECUTIVE SUMMARY................................................................................................... 1
A. Introduction and Policy Statement.............................................................................................1
B. Purpose.......................................................................................................................................1
C. Regulatory Requirements...........................................................................................................2
D. Water Resource Management Related Agreements ..................................................................2
E. Surface Water Management Plan Content.................................................................................3
F. Recommendations......................................................................................................................5
SECTION II – LAND AND WATER RESOURCE INVENTORY.......................................................... 6
A. Introduction................................................................................................................................6
B. Physical Environment ................................................................................................................6
C. Human Environment................................................................................................................10
D. Surface Water System..............................................................................................................12
E. Groundwater Resource Data ....................................................................................................19
SECTION III – ESTABLISHMENT OF GOALS AND POLICIES ....................................................... 22
A. Water Quantity.........................................................................................................................22
B. Water Quality...........................................................................................................................24
C. Erosion and Sedimentation Control .........................................................................................26
D. Wetlands ..................................................................................................................................27
E. Groundwater ............................................................................................................................29
F. Recreation, Fish and Wildlife ..................................................................................................29
G. Enhancement of Public Participation, Information and Education..........................................30
SECTION IV – ASSESSMENT OF PROBLEMS AND CORRECTIVE ACTIONS............................ 32
A. River and Surface Water Quality.............................................................................................32
B. Flooding and Rate Control Issues ............................................................................................33
C. Impacts of Water Quantity or Quality Management Practices on Recreational Opportunities35
D. Impacts of Stormwater Quality on Fish and Wildlife Resources ............................................36
E. Impacts of Soil Erosion on Water Quality and Quantity .........................................................36
F. General Impact of Land Use Practices, and in Particular, Land Development and Wetland
Alternation on Water Quality and Water Quantity ..................................................................37
G. Adequacy of Existing Regulatory Controls to Manage or Mitigate Adverse Impacts on
Public Waters and Wetlands ....................................................................................................38
H. Adequacy of Programs to Limit Soil Erosion and Water Quality Degradation ......................38
I. Adequacy of Existing Programs to Maintain the Tangible and Intrinsic Values of Natural
Storage and Retention Systems................................................................................................39
J. Adequacy of Capital Improvements Program to Correct Problems Related to Water Quality,
Water Quantity Management, Fish and Wildlife Habitat, Public Waters and Wetland
Management, and Recreational Opportunities.........................................................................39
K. Future Potential Problems Anticipated to Occur Within Next 20 Years Based on Growth
Projections and Planned Urbanization .....................................................................................40
SECTION V – IMPLEMENTATION PROGRAM .................................................................................. 42
A. City Regulatory Controls .........................................................................................................42
B. Management Programs ............................................................................................................43
C. Stormwater Design and Performance Standards......................................................................44
D. Capital Improvements Program ...............................................................................................45
E. MS4 Phase II Storm Water Pollution Prevention Program .....................................................46
F. Measures of Success........................................................................................................................ 46
SECTION VI – IMPLEMENTATION PRIORITIES AND FINANCIAL CONSIDERATIONS......... 47
A. Implementation Priorities.........................................................................................................47
B. Financial Considerations..........................................................................................................48
C. Funding Sources.......................................................................................................................49
SECTION VII – STORMWATER MANAGEMENT PLAN AND EROSION CONTROL
STANDARDS.............................................................................................................................................. 50
SECTION VIII – AMENDMENT PROCEDURES.................................................................................. 55
TABLE OF CONTENTS
TABLES
Table 1 – Average Climate Data For Minneapolis and St. Paul............................................................7
Table 2 – Curve Numbers Used for City Model......................................................................................... 16
Table 3 – MDNR Water Appropriation Permits......................................................................................... 20
Table 4 – Implementation Program Priorities ………………………………………………………...47
FIGURES
Figure Following Page
FIGURE 1 – Location Map....................................................................................................................6
FIGURE 2 – 2 Year - 24 Hour Rainfall Amounts .................................................................................7
FIGURE 2A – 10 Year - 24 Hour Rainfall Amounts ............................................................................7
FIGURE 3 – 100 Year – 24 Hour Rainfall Amounts ................................................................................... 7
FIGURE 4 – General Surficial Geology................................................................................................8
FIGURE 5 – Surface Soils Association .................................................................................................8
FIGURE 6 – Land Erosion Succeptibility .............................................................................................9
FIGURE 7 – Scenic Areas Map...........................................................................................................10
FIGURE 8 – Existing Land Use Map..................................................................................................10
FIGURE 9 – Future Land Use Map.....................................................................................................10
FIGURE 10 – Private (ISTS) Sanitary Sewer Locations.....................................................................11
FIGURE 11 – Potential Pollutant Sources...........................................................................................13
FIGURE 12 –NWI Wetland & Protected Water Map .........................................................................12
FIGURE 13 – FEMA Flood Boundary And Floodway Map...............................................................13
FIGURE 14 – Watershed Map.............................................................................................................14
FIGURE 15 – Critical Areas Map .......................................................................................................19
TABLE OF CONTENTS
APPENDICES
Appendix A – Significant Natural Features and Potential Pollutant Sources
Appendix B – MDNR Protected Waters and Wetlands Map, United States Fish and Wildlife Service
National Wetlands Inventory Maps and Washington County Hazardous Waste Generators List
Appendix C – Metropolitan Mosquito Control District Map
Appendix D – Cowardin and Circular 39 Wetland Classifications
Appendix E – FEMA – Floodway Maps and Flood Insurance Study
Appendix F – SWWD Stormwater Management Plan Guidelines and Watershed District Rules
Appendix G – Subwatershed and Drainage District Peak Flow Rates and Ponding Elevations, General
Land Use Curve Numbers
Appendix H – River Development District Ordinance
Appendix I – Floodplain District Ordinance
Appendix J – Infiltration Basin Design Guidelines
MAPS
Map 1 – Storm Water Drainage and Structure Map
STORMWATER AND SURFACE WATER ACRONYM EXPLANATIONS (website links provided for more information where applicable)
BFE – Base Flood Elevation http://www.fema.gov/plan/prevent/floodplain/nfipkeywords/base_flood_elevation.shtm
BMP – Best Management Practice
BWSR – Minnesota Board of Water and Soil Resources www.bwsr.state.mn.us
CERCLIS – Comprehensive Environmental Response, Compensation, and Liability Information System
http://www.epa.gov/superfund/sites/cursites/index.htm
CIP – Capital Improvements Program
CN – Curve Number http://directives.sc.egov.usda.gov/17752.wba
DWSMA – Drinking Water Supply Management Area http://www.health.state.mn.us/divs/eh/water/swp/whp/index.htm
EPA – Environmental Protection Agency www.epa.gov
FEMA – Federal Emergency Management Agency www.fema.gov
FIRM – Flood Insurance Rate Map http://www.fema.gov/library/viewRecord.do?id=1480
FIS – Flood Insurance Study http://www.fema.gov/library/viewRecord.do?id=1480
FWS – Fish and Wildlife Service www.fws.gov
GIS – Geographical Information Systems
HEC – RAS-Hydrologic Engineering Centers River Analysis System www.hec.usace.army.mil
HSG – Hydrologic Soil Group http://directives.sc.egov.usda.gov/viewerFS.aspx?hid=21422
HWL – High Water Level
IDF – Intensity Duration Frequency
ISTS – Individual Sewage Treatment Systems www.pca.state.mn.us/programs/ists/
LOMR – Letter of Map Revision http://www.fema.gov/library/viewRecord.do?id=1480
LGU – Local Government Unit www.bwsr.state.mn.us/wetlands/wca/index.html
LWMP – Local Water Management Plan (i.e. Surface Water Management Plan)
MCM – Minimum Control Measure www.pca.state.mn.us/water/stormwater/stormwater-ms4.html
MDNR – Minnesota Department of Natural Resources www.dnr.state.mn.us
MNDOT – Minnesota Department of Transportation www.dot.state.mn.us
MPCA – Minnesota Pollution Control Agency www.pca.state.mn.us
MS4 – Municipal Separate Storm Sewer System www.pca.state.mn.us/water/stormwater/stormwater-ms4.html
MNRRA – Mississippi National River and Recreation Area http://www.nps.gov/miss/
NFRAP – No Further Remedial Action Planned www.pca.state.mn.us/backyard/neighborhood.html
NPDES – National Pollutant Discharge Elimination System http://cfpub.epa.gov/npdes/
NRCS – National Resource Conservation Service www.nrcs.usda.gov
NWI – National Wetland Inventory www.nwi.fws.gov
NWL – Normal Water Level
OHWL – Ordinary High Water Level www.dnr.state.mn.us/waters/watermgmt_section/pwpermits/ohw.html
PWI – Protected Waters Inventory www.dnr.state.mn.us/waters/watermgmt_section/pwi/index.html
RCRA – Resource Conservation and Recovery Act http://www.epa.gov/epawaste/inforesources/online/index.htm
SCS – Soil Conservation Service (see Natural Resource Conservation Service)
SSTS – Subsurface Sewage Treatment Systems (see ISTS)
SWCD – Soil and Water Conservation District www.co.steele.mn.us/ENVSERV/envserv.html
SWPPP – Storm Water Pollution Prevention Plan or Program
SWWD – South Washington Watershed District http://www.swwdmn.org/
TR-20 – Technical Release 20 http://www.wsi.nrcs.usda.gov/products/w2q/H&H/docs/other/TR20_user_man.pdf
TMDL – Total Maximum Daily Load www.pca.state.mn.us/water/tmdl/index.html
USCOE – United States Corps of Engineers www.mvp.usace.army.mil
USDA – United States Department of Agriculture (see Natural Resource Conservation Service)
VIC – Voluntary Investigation and Cleanup www.pca.state.mn.us/cleanup/vic.html
WCA – Wetland Conservation Act www.bwsr.state.mn.us/wetlands/wca/index.html
WMO – Watershed Management Organization(s) (see MN State Statute 103B.205)
1
SECTION I – EXECUTIVE SUMMARY A. Introduction and Policy Statement
The City of St. Paul Park (City) has prepared this Surface Water Management Plan (SWMP) to provide the
City and its residents with direction concerning the administration and implementation of surface water
management activities within the community. The SWMP inventories City land and water resources and
presents water management policies and goals, which address both known surface water-related problems
and concerns about future development activities. The SWMP also presents the information needed to
comply with the requirements of the federal, state and regional regulatory agencies involved in surface
water management.
Policy Statement: The City of St. Paul Park is committed to a goal of nondegredation and no adverse
impact to area surface waters. To accomplish this goal, the City will demonstrate through this SWMP:
• Performance measures for all proposed stormwater treatment devices;
• Proposed plans that will require stormwater management, rate and volume control, and erosion
control BMP’s protection measures that will require City approval before work can commence;
• Performing proper maintenance for public works activities (i.e. street sweeping, cleanup of City
parks, etc.);
• Public education on water resource management;
• Construction site enforcement of stormwater BMP’s; and
• Providing the necessary funds to implement stormwater management plans, erosion control plans,
public education, and construction site enforcement.
B. Purpose
The general purposes and objectives of the St. Paul Park SWMP are as follows:
• Protect, preserve, and use natural surface and groundwater storage and retention systems;
• Minimize public capital expenditures needed to correct flooding and water quality problems;
• Identify and plan for means to effectively protect and improve surface and groundwater quality;
• Establish uniform local policies and official controls for surface and groundwater management;
• Prevent erosion of soil into surface water systems;
• Promote groundwater recharge;
2
• Protect and enhance fish and wildlife habitat and water recreational facilities; and
• Secure the other benefits associated with the proper management of surface and groundwater.
C. Regulatory Requirements
In 1982, the Minnesota Legislature adopted The Metropolitan Surface Water Management Act requiring all
watersheds within the Twin Cities seven county metropolitan area to be incorporated into watershed
management organizations (WMO’s) and the preparation and adoption of watershed management plans by
each of the WMO’s. The Act also requires that Local Governmental Units prepare local surface water
management plans which include the official controls and capital improvements necessary to bring each
local surface water management into conformance with its respective WMO plan.
The City of St. Paul Park is entirely situated within the Mississippi River Watershed. Surface runoff
generally drains from east to west and eventually discharges into the Mississippi River. The South
Washington Watershed District is the WMO that has jurisdictional control over all drainage basins within
the city. The SWMP is intended to meet the requirements of the following regulatory documents:
• Metropolitan Surface Water Management Act - Minnesota Statutes Chapter 103B.
• Metropolitan Area Local Water Management - Minnesota Rules Chapter 8410.
• Minnesota Wetland Conservation Act of 1991 and subsequent rules and amendments.
• State and Federal laws pertaining to National Pollution Discharge Elimination System
(NPDES) permitting for stormwater outfalls to designated drainage ways.
• Erosion Control Guidelines and Best Management Practices prepared by the Minnesota Pollution
Control Agency.
• Critical Area Executive Order 79-19 for applicable areas within the City.
• South Washington Watershed District (SWWD) Watershed Management Plan, Adopted 2007.
• Met Council 2030 Water Resources Management Policy Plan, Adopted 2005.
• Washington County Groundwater Plan, Adopted 2003.
D. Water Resource Management Related Agreements
The City of St. Paul Park currently has no water resource management related joint powers agreements with
adjacent communities or private parties. The SWWD did obtain jurisdictional watershed control on May
28, 2003.
3
E. Surface Water Management Plan Content
The City of St. Paul Park’s SWMP has been developed to meet the needs of the community and address the
management planning requirements of the Metropolitan Surface Water Management Act. The SWMP has
been prepared in general accordance with Minnesota Rules Chapter 8410 and follows the plan outline
identified in the rules.
The following summaries identify the major sections of the SWMP and where information can be located in
the plan document:
EXECUTIVE SUMMARY (SECTION I) This section presents an introduction for the local water management plan, and a summary of all the
sections of this Surface Water Management Plan. This section also summarizes strategic
recommendations for consideration by the City in implementing the SWMP.
LAND AND WATER RESOURCE INVENTORY (SECTION II)
This section categorizes a wide range of information under the subsections entitled Physical
Environment, Human Environment, Surface Water System, and Groundwater Resource Data. The
subsections provide information and references regarding water resource and physical factors within
the City of St. Paul Park including the following:
• Location
• Precipitation data for hydrologic/hydraulic review and design
• Geologic and topographic information
• Surface soils and groundwater information
• Land Erosion (Runoff) Susceptibility
• Unique features and scenic areas
• Land use and public utility services
• Water-based recreational areas and land ownership
• Potential pollutant sources
• Public waters and wetlands
• Flood Insurance Studies and surface water drainage information
• City subwatersheds and Storm water modeling data, limitations and results
4
• Flood problem areas and surface water quality
• Specific City Ordinances pertaining to Storm water management
• Groundwater resource data
ESTABLISHMENT OF POLICIES AND GOALS (SECTION III)
This section outlines goals and policies addressing water resource management needs of the City
and their relationship with Regional, State, and Federal goals and programs. Goals and policies
relating to the following issues are presented:
• Water quantity
• Water quality
• Erosion and sedimentation
• Wetlands
• Groundwater
• Recreation, fish and wildlife
• Enhancement of public participation
ASSESSMENT OF PROBLEMS AND CORRECTIVE ACTIONS (SECTION IV)
This section provides an assessment of existing or potential water resource related problems within
the City. This section also describes potential structural, nonstructural and programmatic solutions
on correction actions to the identified problems.
IMPLEMENTATION PROGRAM (SECTION V)
This section identifies the regulatory controls, management programs, storm water design and
performance standards, and capital improvements to be utilized by the City in implementing this
SWMP.
IMPLEMENTATION PRIORITIES AND FINANCIAL CONSIDERATIONS
(SECTION VI)
This section presents improvement priorities and financial considerations that can be reasonably
funded and implemented by the City in the near and longer-term future. This section also identifies
the estimated costs and potential funding sources for implementing the proposed regulatory controls
and programs.
5
STORMWATER MANAGEMENT AND EROSION CONTROL PLAN STANDARDS
(SECTION VII) This section addresses stormwater management and erosion control standards the City reviews and
enforces when new development or redevelopment occurs. Implementation of these standards will
help minimize the impact of stormwater runoff from the site and to receiving downstream areas.
AMENDMENT PROCEDURES (SECTION VIII)
This section presents the expected longevity of the SWMP (to the year 2019) and the process for
making amendments consistent with the future WMO plan.
F. Recommendations The following recommendations are presented for the City’s consideration based upon the information
compiled for this SWMP:
• The SWMP should be used to guide future water resource management decisions and stormwater
related issues in existing and projected urban growth areas.
• The SWMP should be used as part of the City’s capital improvements planning process to address
and prioritize necessary stormwater related infrastructure needs.
• The City should examine existing and potential funding sources available for implementing
stormwater regulatory controls and improvements. Development of a stormwater area charge
should be considered for newly developing areas to address the off-site impacts of urbanization.
• The City should consider the additional staff time and financial resources required to implement this
SWMP, develop additional revenue sources, and budget accordingly.
• The City should develop a Water Resource Library at City Hall containing this SWMP and other
water resource related information and public educational materials.
• The SWMP should be updated if there are changes to the City’s projected land use and urbanization
areas.
• The SWMP provides a general framework for addressing existing and future surface water
management issues within the City. Additional studies may be required when specific development
proposals are prepared. Final high-water levels governing building elevations adjacent to ponding
areas and floodplains should be established as development occurs or when stormwater
management facilities are designed for construction.
6
SECTION II – LAND AND WATER RESOURCE INVENTORY
A. Introduction
This section provides a generalized description and summary of land and water resource factors affecting
the water resources within the City of St. Paul Park. The Physical Environment subsection presents local
information on precipitation, geology, topography, soils, fish and wildlife habitat and unique features and
scenic areas. The Human Environment subsection identifies local land use, public utility services, water
based recreational areas and known pollutant sources. The Surface Water Systems subsection presents
information on the City’s drainage patterns, hydrologic systems, public waters and wetlands, floodplain
areas, flood studies, shoreland management and water quality. The Groundwater Resource Data subsection
presents the information necessary for the City to begin addressing groundwater issues.
Much of the information contained within this section was compiled from available governmental sources.
Whenever possible, the location of the information or additional resources have been identified or
referenced.
B. Physical Environment
1. Location
The City of St. Paul Park occupies approximately 3.1 square miles in southwestern Washington
County as shown in Figure 1. The communities adjacent to St. Paul Park are Newport, Cottage
Grove and Grey Cloud Township. To the west of St. Paul Park lies the Mississippi River. All of St.
Paul Park’s stormwater runoff will eventually drain to the Mississippi River. Additional
information on the City’s water resources is contained in the following sections.
2. Precipitation
The climate of the Minneapolis/St. Paul metropolitan area is a humid continental climate with
moderate precipitation, wide daily temperature variations, warm humid summers and cold winters.
The total average annual precipitation is approximately 33 inches of which approximately 1/3
occurs in the months of June, July and August. The annual snowfall average is about 52 inches and
is equivalent to approximately 5.2 inches of water. The average monthly temperatures,
precipitations, and snowfalls are shown on Table 1.
7
TABLE 1 – AVERAGE CLIMATE DATA FOR ST. PAUL
Month Temperature (°F) Precipitation (Inches) Snowfall (Inches)January 14.5 1.02 12.2 February 21.4 0.78 7.5 March 32.8 1.92 9.7 April 47.2 2.54 3 May 59.9 3.73 0 June 68.4 4.98 0 July 73 4.41 0
August 70.8 4.37 0 September 61.8 3.2 0
October 49.8 2.51 0.4 November 33.3 2.09 9.3 December 19.5 1.04 10.3
Annual Average 46.00 32.59 52.40 Source: Minnesota State Climatology Office
Figures 2, 2a and 3 show the 24-hour rainfall amounts of the 2-year, 10-year and 100-year storm
events. The following values are to be used in the evaluation and design of all major stormwater
facilities in the City. See SWWD Standards Manual Section 4.1.3 for additional
2-Year 10-Year 100-Year
Rainfall Depth 2.8” 4.2” 6.3”
Probability (1-year) 50% 10% 1%
The SCS Type II distribution is a synthetic storm hyetograph for use in Minnesota for storms of 24-
hours in duration. These storms consist entirely of rainfall. For determination of snowmelt events,
the 100-year 10-day event was used based on information presented in the NRCS TR-60 document.
Additional climatological information for the area can be found in the Minnesota Hydrology Guide
prepared by the NRCS, the U. S. Weather Bureau Technical Papers 40 and 49, and the NRCS
National Engineering Handbook - Hydrology - Section 4.
3. Geology
The general geology of Washington County and the City of St. Paul Park has been compiled by the
Minnesota Geological Survey in a document titled Geologic Atlas of Washington County
Minnesota (L.Swanson and G. Meyer, Editors, 1990).
8
The surficial geology in the City is shown in Figure 4. In the east part of the City it consists of
mainly Terrace Deposits such as sand and gravel. The western half of the City consists of similar
Terrace Deposits such as coarse sand and gravel, capped in places by as much as 10 feet of loamy
sand. Bedrock is common within 10 feet of the surface in the western areas. There is a small
pocket of Postglacial Deposits like peat and organic-rich sediment in the southeast part of the City.
Floodplain Alluvium; consisting of stratified silt loam, loam and very fine, sandy loam with minor
interbeds of fine, sandy to clayey sediment and organic matter exists along the Mississippi River.
4. Topography
The City of St. Paul Park topography consists of a generally flat terrain. Surface elevations range
from 800 feet above sea level on the eastern part of the city, to 700 feet above sea level on the
western part. Most of the surface run-off drains west to the Mississippi River, which has an
approximate elevation of 675 feet above sea level.
5. Soils
The USDA Natural Resource Conservation Service (formerly the Soil Conservation Service)
prepared the Soil Survey for Washington County in 1980. This reference maps the location of
specific soil types throughout the City of St. Paul Park and provides detailed data on the typical
characteristics of each soil type. The patterns are shown in Figure 5. For the City of St. Paul Park,
the predominant soil types in the city are loam, loamy sand, sandy loam, silt loam and urban land.
A brief narrative of the soil types for the City is found below. The names associated for each soil
type as given by the Soil Survey appear in parenthesis.
a. Copaston-Sparta
Loam (Copaston)
This type of soil will experience average surface drainage. Typical permeability rates would
be in the range of 0.6 to 2.0 inches per hour (above bedrock). Soils will typically have
bedrock formations as high as 1 foot below the soil surface elevation. The soil is generally
unsuitable for septic fields and for infiltration due to shallow depths to bedrock.
Loamy Sand (Hubbard, Mahtomedi, Sparta)
This type of soil will experience excessive surface drainage. Typical permeability rates
would be from 6.0 to 20.0 inches per hour. The high sand content of soils are good for
septic fields provided the fields are built properly. Groundwater contamination is a
9
significant concern due to the high drainage and the soils inability to trap pollutants.
Groundwater elevations would generally extend beyond 6 feet below surface. Extra care
will need to be taken if grading occurs because of the high erosion potential.
Sparta is well suited for building sites, however the Copaston soils are limited by the
shallowness of the hard bedrock.
b. Sparta-Dickman-Hubbard
Sandy Loam (Chetek, Dickman)
This type of soil will experience moderately to excessive surface drainage. Typical
permeability rates would be from 2.0 to 20 inches per hour, with higher rates being achieved
approximately 2 feet below the surface. This soil type also experiences a high sand content
and has generally the same properties as the Loamy Sand classes.
Sandy Loam (Hubbard)
This type of soil will experience excessive surface drainage. Typical permeability rates
would be from 6.0 to 20 inches per hour. The risk of pollution of underground water
supplies and nearby lakes and streams is large if septic tank absorption fields or other
sanitary facilities are placed on these soils.
6. Land Erosion (Runoff) Susceptibility
Land that is located on high sloping land, or has been previously been developed has a greater
likelihood of generating more runoff than in areas that has not been developed or are located on
low-sloping areas. Figure 6 shows the areas and their likelihood of generating runoff.
Areas in medium or high susceptible zones have a greater chance of producing runoff with high silt
concentrations and/or urban pollutants. Great caution is needed in high slope areas especially if
grading or constructing is taking place. The disturbed soil has a greater chance of washing or
blowing away due to the high sand and fines content. Establishing or maintaining vegetation on
exposed soil in these medium or high zone areas is critical to keep silt and urban pollutants from
washing into the receiving storm sewer lines and ultimately reaching the Mississippi River. Best
Management Practices (BMPs) for erosion and sediment control are to be a part of all new
development and redevelopment projects in all susceptibility areas.
10
7. Unique Features and Scenic Areas
The MDNR Natural Heritage and Non-game Research Program has identified several rare plant and
animal species, as well as other significant natural features, within and near the City of St. Paul
Park. According to MDNR records, there are no occurrences of any rare plant or animal species
within the city limits of St. Paul Park. In the southern undeveloped portion of St. Paul Park adjacent
to the Mississippi River, there exists several occurrences of rare species. Those occurrences include
Bald Eagle nesting areas, freshwater mussels species in the Mississippi River, Floodplain Forests,
and River Cliffs. Proper actions are to be taken in conjunction with the MDNR before any land
alteration or grading is scheduled to occur to ensure development will not affect rare plant or animal
species.
The City does not contain any state or federal owned wildlife and waterfowl management areas or
and state or federal owned scientific and natural areas. However, there are areas that have dense
forested cover and those areas are shown in Figure 7. The majority of dense forested cover lies
adjacent to the Mississippi River. Those forested areas have scenic value and care should be taken
to maintain and preserve the forests where feasible.
The area located near the shoreline of the Mississippi is located within the Critical Area Corridor as
established under Executive Order 79-19. The main purpose of establishing the Critical Area
Corridor was to protect the natural resources and preserve the natural, aesthetic, cultural, and
historical value for the public use along the shoreline of the Mississippi. The City governs land use
within this corridor through the River Development (RD) district zoning regulations. The Critical
Area Corridor boundary is shown on Figure 15. Additional information about the RD district can
be found later in this section under River Development and Floodplain Ordinances.
C. Human Environment
1. Land Use
The City’s Comprehensive Plan contains both existing Land Use (which has been updated in 2008),
as shown in Figure 8, and the Proposed Land Use Plan (extending to the year 2030) which is shown
in Figure 9. The City has annexed part of Grey Cloud Island Township. The development area has
the potential to double the residential population of the City of St. Paul Park. Outside of the Grey
11
Cloud Island area, 9.3 % of the land in St. Paul Park remains vacant as of 2008. The potential for
re-development does exist and those areas are shown in the Proposed Land Use Plan.
2. Public Utilities Services
The City of St. Paul Park has municipal sanitary sewer and watermain available in all developed
areas. Properties near the Mississippi River (mainly in the southwest) and a few in the northeastern
part of the city are not connected to the public sanitary sewer or water systems; the properties are
serviced by individual sewage treatment systems (ISTS) and by private wells. These private on-site
sewage treatment systems and private wells are designated on Figure 10. New development in the
southern part of the city would include gravity and forcemain wastewater operation to discharge
into the city’s existing sewer system. Water main would be connected to the City’s water system
and may require new wells, pump houses, and a water tower.
The existing public storm sewer system within the City primarily consists of six piping systems.
Four of the systems drain into the Mississippi River while the other two discharge into local ponds.
Drainage ditch systems also exist in the City paralleling the two railroad lines. Future development
would strongly emphasize infiltration as a plan. The sizes of trunk storm sewer mains and slope
information can be found on the overall Storm Sewer Map located on Map 1. Additional
information on storm sewer systems and drainage features are presented later in this SWMP.
3. Public Areas for Water Based Recreation
The only water body used for recreation in St. Paul Park is the Mississippi River, which borders the
City to the west. The river is a regional water resource and has many recreational uses including
fishing, swimming and boating. Public boat access is provided at the City’s Lion’s Park.
4. Potential Pollutant Sources
Various land use practices have the potential to contaminate local surface waters and groundwaters.
There is significant contamination potential at open and closed landfills, dumps, hazardous waste
sites, and underground and aboveground storage tanks. In-place or abandoned wells can allow
contamination of groundwater if not properly constructed or taken out of service. Figure 10
identifies potential sources of surface water and groundwater contamination within the City of St.
Paul Park. Locations in the City that have Hazardous Waste Generator Permits can be found in
Appendix B along with relevant data obtained from Figure 10. The potential pollutant source
12
information in the table was obtained from the MPCA, the Minnesota Department of Health
(MDH), and Washington County and is shown on Figure 11.
Within the city of St. Paul Park, the Marathon-Ashland Petroleum Plant has an industrial discharge
NPDES permit. See Section II.D.9 below for additional information including discharge readings.
The city does have private septic systems as mentioned earlier. The ISTS’s may be a pollution
concern due to the presence of sandy soils with high soil transmission rates and/or non-properly
functioning septic tanks. Washington County currently has a program that monitors existing septic
systems and has replacement procedures for failing systems.
D. Surface Water System This section summarizes the available surface water data within the City. Additional information is
included in the Appendices of this SWMP.
1. Public Waters and Wetlands
The MDNR currently lists only one protected water, wetland or watercourse within the City of St.
Paul Park of 2.5 acres or larger (excluding the Mississippi River). Minnesota Chapter 103G
provides specific criteria for protected status and the MDNR Protected Waters and Wetlands (PWI)
map identifies the protected water. In addition to the MDNR PWI Maps, National Wetlands
Inventory (NWI) Maps, prepared by the U.S. Fish and Wildlife Service, and Mosquito Wetland
Inventory Maps prepared by The Metropolitan Mosquito Control District are included in this
SWMP. Figure 12 is a compilation of protected waters and wetlands from the MDNR maps and the
U.S. Fish and Wildlife Maps. Appendix B shows the full size U.S. Fish and Wildlife Wetland
Inventory Maps and the MDNR Protected Water Map. Appendix C shows the Mosquito Wetland
Inventory Maps.
The various wetland inventories identify and classify wetlands based on two primary systems.
Those classification systems are the Circular 39 and the Cowardin. The U.S. Fish and Wildlife
Service developed their maps using both systems. The MDNR classified their protected waters by
using the Circular 39 system, and the NWI maps were defined by the Cowardin System. The
Minnesota Board of Water and Soil Resources (BWSR) has prepared a brochure that gives a brief
explanation of the two classification systems including photos of the different types of wetlands. It
13
also provides translations between the two systems. The brochure is included in Appendix D. The
classification systems were developed for a wide number of purposes and to assist in meeting
differing water resource management goals. Although not comprehensive, these inventories can all
be utilized in determining whether wetlands are present on a specific property and how land uses
may be affected.
The City of St. Paul Park has no near-term plans to inventory the functional values of wetlands
within the community but will review the functional values of impacted wetlands on a case-by-case
basis in accordance with Minnesota Statue, Section 103B.3355 during City review of individual
project proposals. The City has accepted responsibility as the Local Government Unit under the
Minnesota Wetlands Conservation Act and will review projects impacting wetlands in accordance
with State wetland laws and rules. Section III of this SWMP further defines the Cities review
process for projects affecting wetlands.
2. Flood Insurance Studies
In 1980, the Federal Emergency Management Agency (FEMA) completed a Flood Insurance Rate
Map (FIRM) and a Floodway Map for the City of St. Paul Park. The FEMA Community Number
for the City of St. Paul Park is 270514. The FIRM identifies areas within the City as being within
Zone A12: 100-year flood plain, Zone B: 100-500 year flood plain, or Zone C: Areas of minimal
flooding. Figure 13 shows the 100-year flood plain as shown in the FIRM. The Floodway Maps
show identical flood areas as those on the FIRM. The Floodway Maps identify cross-sectional areas
that are shown in corresponding Flood Insurance Study Report (FIS).
The FIRM and Floodway maps only depict areas prone to flooding adjacent to the Mississippi
River. The maps do not evaluate areas prone to flooding that are located in the upland areas east of
the Mississippi. The study boundary extends to the current city limits.
The FIS evaluated streamflow records in the Mississippi River from 1889 through 1969. The
riverbank elevations were generated from aerial photographs and topographic maps with four-foot
contour intervals. The 100-year river flow-rate used for this study and used to determine the 100-
year flood elevations was 160,000 cfs through St. Paul Park. The flow-rate location was 300 feet
upstream from the Robert St. Bridge. Since 1969, there has been no flow-rate that has exceeded the
160,000 cfs level. The highest recorded flow-rate at the Robert St. location post-1965 according to
USGS records was 143,000 cfs, which occurred on April 18th, 2001.
14
The City currently uses the floodplain information to review development proposals based upon the
real extent of flood plains identified in the FIRM. For determination of specific flow rates and
floodplain elevations, an updated hydrologic/hydraulic analysis may be required utilizing accurate
topographic data and water control structures. The full size FIRM and Floodway Map, and also the
FIS for St. Paul Park are contained in Appendix E. Since the FIRM lacks detailed hydrologic
information, this SWMP provides the specific hydrologic/hydraulic analysis that can be used for
community planning, flooding protection and capital improvements.
3. Surface Water Drainage Information
The surface water drainage system consists primarily of catch basins that collect run-off from
developed areas, then drain into trunk storm sewer lines that outlet to ponds, ditches, or the
Mississippi River. The trunk lines that drain directly to the Mississippi do not have any formal
treatment (sedimentation ponds, separators, etc.) before discharging into the river. The other trunk
lines drain to ponds or ditches primary located along the railroad lines and travel north into Newport
or south into Grey Cloud Island Township.
4. City Subwatershed Districts
The city consists of the following six major subwatershed districts: These districts are Highway
East, Marathon-Ashland, Downtown, City-South, West-Bluff, and Grey Cloud Island. The
subwatershed districts were then further divided into smaller sub-districts. Figure 14 shows the
subwatershed districts and sub-districts delineated for this study. A brief narrative about each of the
6 subwatershed districts is listed below.
Marathon-Ashland Subwatershed (MA)
This district contains the area that is occupied by the Marathon Ashland Refinery. Nearly
half of the site is ponded in depressions around the tanks. These depressions keep water
from discharging to the Downtown District. The overflow from the tank areas does not
enter the city’s storm system and the other refinery areas not draining to the tank depressions
sheet flow directly west to the Mississippi River.
West-Bluff Subwatershed (WB)
FIGURE 14: Subwatershed Map
.
No Scale9-14-09
St. Paul Park Surface Water Management Plan
15
This district is the area along the western edge of the City adjacent to the Mississippi River.
The stormwater from the subdistrict sheet flows directly without ponding to the Mississippi
River. There are no existing piped collection systems in this district.
Downtown Subwatershed
There are two existing trunk storm sewer lines, one on Broadway Avenue and one on Eighth
Avenue, which serve the majority of this district. The Eighth Avenue truck line passes
through the WB district and outlets into the Mississippi River. The Broadway trunk line
passes through the MA district and also discharges into the Mississippi River. The WB
district may also get additional surface water drainage if storm sewer overflows occur in the
Downtown District.
City-South Subwatershed
There are two trunk storm sewer lines that serve this district, one on Tenth Avenue and one
on Pullman Avenue. If storm sewer overflows occur in the City-South district the WB
district may also get additional surface water drainage.
Grey Cloud Island Subwatershed (GCI)
Runoff from this district enters the Mississippi River via ditches and sheet drainage across
Grey Cloud Island Township or areas annexed into St. Paul Park from Grey Cloud Island
Township. There are some storm sewer ponding areas that intercept and treat the flows
from the piped systems east of the Railroad tracks. There are no lateral storm sewer
structures with catch basin inlets west of the tracks.
Highway-East Subwatershed
Surface water flows in this district are collected in a ditch system paralleling Highway 61-10
and the Soo line railroad. The ditches gradually run in a northwesterly direction continuing
into the City of Newport. This subwatershed district also includes areas in Newport and
Cottage Grove.
5. Storm Water Modeling Information
As part of the SWMP preparation, a limited hydrologic analysis was conducted. The hydrologic
model utilized the Hydro CAD computer program. Hydro CAD is a hydrologic/hydraulics program
based on techniques developed by the Soil Conservation Service (SCS). The computer model is
16
similar to the SCS TR-20 program, which simulates single storm events. The results of the Hydro
CAD model provide a probability-statistical determination of runoff flow rates, pond volumes and
water elevations.
The analysis was limited to areas within the St. Paul Park vicinity and included drainage ultimately
received by the Mississippi River. The analysis included map and plan review, sub watershed
delineation from Dakota County topography and field reconnaissance, limited storm sewer surveys,
and development of a hydrologic model. The analysis determined hydrologic conditions, and peak
discharge rates for the 5-year and 100-year, 24-hour storm events and the 100-year, 10-day runoff
event.
To determine runoff volumes and flow-rates for each sub watershed, runoff curve numbers (CN)
were used as part of the Hydro CAD (SCS TR-20) program. The CN’s are dependent on land use
and can range from 25 for wooded areas to 98 for impervious surfaces. The CN’s vary based on the
type of soil, cover type or vegetation, and the amount of impervious surfaces in each watershed.
For the 100-year, 10-day snowmelt condition, all areas were given a CN of 98 which approximates
frozen ground conditions.
Due to the presence of sandy soils with good infiltration within the city, the runoff volumes for
developed areas were separated based on direct impervious and indirect impervious areas. Direct
impervious areas do not allow water to pond in grassy or open areas and will travel directly from a
rooftop to the street and then into a catch basin. The indirect impervious areas are able to travel
through open areas before reaching either a pond or catch basin and will generate little runoff. In
accordance with SWWD, CN values listed under hydrologic soil group A will generally not be
accepted where developed conditions are modeled. CN values must not exceed a value of 62.
Table 2 defines the direct impervious content, and curve numbers based on land use.
Table 2. Curve Numbers Used for City Model
Land Use Direct Impervious (fraction per acre)
Direct Impervious
CN
Indirect Impervious/
Open Areas CN Single Family Residential (2-6 housing units per acre) 0.20 98 49
High Density (Multi-Family) Residential >6 units per acre including Apartments/Town homes/Manufactured Homes
0.35 98 49
Commercial/Industrial/Retail 0.60 98 49
17
School 0.50 98 49
Open/Undeveloped/Woods/Parkland (Excluding open water surfaces) 0.0 N/A 39
Highway Right Of Way/Major Highway 0.20 98 49
Agricultural 0.0 N/A 55
Water Surfaces 0.0 N/A 98
Snowmelt/Frozen Ground N/A 98 98
Other Varies
6. Modeling Limitations
The modeling was based on assumed rain events and does not use or contain any calibrated data.
The analysis does not attempt to model the Mississippi River due to the body of water extending
well beyond the City Limits and due to the limitations of the program. This model does not attempt
to establish official 100-year HWL elevations of waterbodies or ponding areas. However, the
analysis does provide a technical tool to address risk and a mechanism to consider various
stormwater-related alternatives. The City should in the future compare the modeling results and
adjust the model if significant rain events (i.e. 5 or 100 year) or snowmelt event (100 year) were to
occur.
The Marathon-Ashland subwatershed was not modeled in the SWMP due to the storm runoff being
entirely contained within the subwatershed. The model will need to be updated if a significant
change to the Marathon-Ashland property is made in the future.
7. Modeling Results
Appendix G provides pertinent hydrologic data for each of the sub districts analyzed in this study.
The analysis results for peak discharge rates, types of flow routing (i.e. pond, storm line, etc.) 100-
year HWL elevations, and ultimate overflow elevations are given. The analysis evaluated existing
conditions. The results also include 5-year and 100-year peak flow rates and approximate flooding
elevations for the current land uses. The model will need to be updated if a substantial (i.e. 5 acres)
land use change occurs that increases the amount of direct impervious area and/or if there are
significant improvements made to the city storm sewer system. Documentation on the Hydro CAD
model and complete input parameters and results are available for review at the City’s Water
Resource Library or contained in the City offices.
18
The areas that are shown to flood for the 5 and 100-year events are indicated on Map 1. Any HWL
that exceeded the Drainage District’s overflow elevation is also indicated on the map. The HWL’s
for the 5 and 100-year events were generally confined to depressed or low-lying areas as determined
by the city’s topography. Upland areas located above the HWL’s may experience some temporary
flooding due to the limited capacity of the collection system. The depth of temporary surface water
in these areas is typically one foot or less.
8. Flood Problem Areas
There are limited number of areas located within the city that may flood based on Hydro CAD
modeling. The modeling shows these areas experience inconvenience flooding (i.e. non life-
threatening) and are not within FEMA 100-year flood plains. The areas shown to flood based on
the HydroCAD model should be monitored by City staff and appropriate measures should be taken
if inconvenience flooding does occur.
9. Surface Water Quality Data
The MPCA has established surface water quality monitoring sites throughout the city. The sites are
all located on the Mississippi River. There is also a monitoring site on the Mississippi River for
industrial discharge, which is taken from the Marathon-Ashland Petroleum plant.
The surface water quality information is also available online through the MPCA’s interactive
website. Also included at the MPCD website are explanations of the water quality measurements
used for each site evaluation. The information can be accessed via the web at:
http://www.pca.state.mn.us/data/edaWater/index.cfm
There are two other sources that can or will provide surface water quality monitoring. Those
sources include The Metropolitan Council (Met Council) and Washington Conservation District
(WCD). Currently, the Met Council does not have surface water monitoring locations in or near the
vicinity of St. Paul Park. The WCD provides monitoring on a volunteer basis. The SWWD is
operating an automated stormwater monitoring site in stormwater C manhole on the west end of 10th
Street. Flow measurements are recorded every 15 minutes and grab and/or composite water quality
samples are collected during snowmelt, baseflow and stormflow to characterize nutrient, sediment
and pollutant loading. The data from that manhole is available from the SWWD or WCD.
19
10. River Development and Flood Plain Ordinances
River Development Zoning District
The City of St. Paul Park has identified lands that lie within its boundaries along the Mississippi
River as Critical Areas. Lands within those areas fall under the City’s River Development District
Zoning Regulations. Any development that will occur within this zone must first receive approvals
from the MDNR before any development can take place. A map showing the Critical Area
boundary is shown in Figure 15.
The River Development District Zone identifies allowable uses, lot areas, and setbacks for
properties that fall within its boundary. In addition, the ordinance identifies other development
criteria including allowable lowest floor elevations, shoreland alterations, building heights, island
preservation, bluff impact zones and permitted use standards. The River Development District
Ordinance is contained in Appendix H.
Floodplain Zoning District
To maintain St. Paul Park’s eligibility in the National Flood Insurance program and to minimize
potential losses due to periodic flooding, the City has prepared and adopted a Floodplain Zoning
District. The flood plain zoning district is an overlay zoning district to existing land use regulations
of the city. The ordinance provides protection for designated areas that will become inundated
during a “regional flood.” A regional flood is defined according to standards set by the MDNR.
The Floodplain District Zoning Ordinance is contained in Appendix I.
E. Groundwater Resource Data
1. Groundwater and Surface Water Appropriations
The City of St. Paul Park’s municipal water supply system is served by four different wells. The
wells are located in the Prairie du Chien-Jordan Aquifer. As required by the well permits, the City
completes and submits to the MDNR the Annual Report for water use. The Annual Report is
available for review at City Hall and the MDNR. Additional information on the City’s municipal
water supply system is contained in the City’s Water Supply Plan available in the City’s Water
Resource Library.
Table 3 identifies the permitted city appropriations, flow rates, and reported pumpage volumes.
20
Table 3, MDNR Water Appropriation Permits
Permittee Appropriation Type-Source
Pumprate (m3/day)
Pumpage (Million
Gal/Year) City of St. Paul Park-Well 1 Groundwater Well 0 0
City of St. Paul Park-Well 2 Groundwater Well 604 58,206,000
City of St. Paul Park-Well 3 Groundwater Well 820 79,065,000
City of St. Paul Park-Well 4 Groundwater Well 570 54,957,000 Source: MDNR
2. Wellhead Protection Plan
This report documents the delineation of the wellhead protection areas and drinking water supply
management areas for the drinking water supply wells operated by the City of St. Paul Park,
PWSID No. 1820018. The delineation was performed in accordance with rules (Minnesota
Rules 4720.5100 to 4720.5580) for preparing and implementing wellhead protection measures for
public water supply wells. The Minnesota Department of Health (MDH) administers the rules for
the Wellhead Protection Plans. Key documentation relative to St. Paul Park's wellhead protection
effort is included in this report. Background data including City well pumping records, DNR
appropriations and pumping records for community and non community wells, water chemistry and
tritium analysis, well logs and geologic data were collected and reviewed prior to beginning the
modeling portion of the Wellhead Protection Plan.
Some of the recommendations within the Wellhead Protection Plan are: conducting an in depth
contaminant source inventory for the high vulnerability DWSMA (Drinking Water Supply
Management Area), reviewing the land uses and detailing a well inventory within the entire
DWSMA, additional pump testing on municipal wells 3 and 4 to determine presence of faults and
fractured bedrock, updating the City Water Supply Plan, and developing sound policies for source
water protection within the DWSMA.
3. Groundwater Plan
Washington County has adopted their Groundwater Plan effective from 2003-2013 which includes
the City. The plan represents a variety of information on groundwater-related issues including an
inventory of groundwater resources, potential contaminant sources, management of the resource,
21
and local groundwater protection strategies. Many of the recommended protection strategies and
actions are directed towards local levels of government (i.e., Cities and Townships). The SWMP
includes goals and polices which are consistent with the Groundwater Plan.
Another source of groundwater data and information is the 1990 Washington County Geologic
Atlas prepared by the Minnesota Geologic Survey. The atlas provides information on bedrock
geology, surficial geology, depth to bedrock, bedrock topography, hydrogeology, bedrock
hydrogeology, sensitivity of the Prairie du Chien-Jordan Aquifer to pollution, and well construction.
The Washington County Groundwater Plan and the Geologic Atlas are available for review at the
WCD office. The Washington County Groundwater Plan is also available online at:
http://www.co.washington.mn.us/client_files/documents/phe/ENV/ENV-2003GroundwaterPlan.pdf
22
SECTION III – ESTABLISHMENT OF GOALS AND POLICIES The City of St. Paul Park has developed the goals and policies contained in this section to conform with the
water resource purposes specified in Minnesota Statute Section 103B.201. They have been developed to
avoid conflict with existing State, Regional, and County goals and policies. The general purposes of the
goals and policies are as follows:
• Protect, preserve, and use natural surface and groundwater storage and retention systems;
• Minimize public capital expenditures needed to correct flooding and water quality problems;
• Identify and plan for means to effectively protect and improve surface and groundwater
quality;
• Establish uniform local policies and official controls for surface and groundwater
management;
• Prevent erosion of soil into surface water systems;
• Promote groundwater recharge;
• Protect and enhance fish and wildlife habitat and water recreational facilities;
• Secure the other benefits associated with the proper management of surface and
groundwater.
The goals and policies developed by the City address water quality, water quantity, erosion and sediment
control, wetlands, groundwater, recreation, fish and wildlife, and enhancement of public participation.
Outlined below are the goals and policies developed for each of the above topics.
A. Water Quantity
Goal: To limit public capital expenditures necessary to control excessive volumes and rates
of runoff.
Policies:
1. The city will require that proposed stormwater discharges as a result of development be
consistent with the subwatershed and subdistrict discharge limits and water levels identified
in this SWMP. Proposed projects must not exceed the existing runoff rates for the 2, 10, and
100 year 24 hour duration rainfall event and must maintain the annual average
predevelopment infiltration capacity of the site.
23
2. The City will require on-site stormwater facilities for land development projects to maintain
pre-development hydrology. The existing regional stormwater facilities will be utilized for
the existing runoff of previous development.. For large land development projects, the City
will determine whether regional stormwater facilities can be utilized and the level of City
participation in planning and construction.
3. The City will review downstream stormwater-related impacts (within the community) of
development proposals and proactively address water resource-related concerns.
4. The design of new stormwater storage facilities and trunk lines will accommodate the 100-
year storm event. Additional information on stormwater design standards is contained in
Sections V and VII.
5. Stormwater facilities receiving discharges from adjacent communities will be designed to
accommodate those existing runoff rates and anticipated volumes.
6. Peak stormwater rates discharging from the City into an adjacent community will not
exceed pre-development discharge rates without notifying and obtaining approval from the
adjacent community or communities.
7. The existing 100-year flood elevation of local water resources will be maintained. Filling or
development in identified critical storage areas is not allowed.
8. Surface elevations for new buildings will be a minimum of 3 feet above projected 100-year
flood levels and the MDNR established OHWL’s.
9. The City will develop positive outlets for landlocked areas to control water levels on the site
or areas adjacent to the developing property. The outlets shall incorporate storm water
volume controls where feasible and shall not significantly impact downstream flooding.
10. The City will utilize of natural ponding areas and wetlands for stormwater storage and
treatment if not in conflict with the classifications and management strategies of this
SWMP, and the recommendations for Protect, Manage 1, Manage 2, and Urban
Management Wetlands set by the SWWD.
24
11. The City will minimize the amount of direct impervious surface planned for any
development. The city will use of natural drainage ways for conveying stormwater,
provided the drainage ways can properly channel the stormwater flows and volumes before
ultimately reaching an existing or proposed storm sewer line.
12. Enhanced filtration practices will be used in areas where the present or future land use does
not have a significant potential to contaminate either stormwater runoff flows or
groundwater infiltration.
13. Public stormwater facilities will be regularly inspected and maintained as necessary for
adequate operations. For private stormwater facilities, the City will require a maintenance
agreement, which identifies adequate inspection and maintenance methods for stormwater
facilities as a part of the development documents.
14. Wetlands within the City will be protected to assure that the wetland’s values for providing
water quantity benefits will not be significantly impacted.
B. Water Quality
Goal: To maintain or improve water quality of City waterbodies and wetlands.
Policies:
1. In the design and construction of new stormwater conveyance systems, or modification of
existing systems, pretreatment of stormwater runoff will be required prior to discharge to a
City waterbody or wetland. Pretreatment methods shall Best Management Practices
identified in the current MPCA Minnesota Stormwater Manual or equivalent performance
standards. Additional information on design standards are found in Sections V and VII.
2. Ponding areas constructed for water quality improvements shall include a skimmer, if
feasible, at the pond outlet to remove oil and other floating materials in stormwater runoff.
3. The City will develop a maintenance program to regularly inspect and maintain public
stormwater management facilities to assure their effectiveness per NPDES Phase II
25
Municipal Separate Storm Sewer System (MS4) Requirements. The City will require the
owner of private stormwater facilities to execute a maintenance agreement with the City for
regular inspection and maintenance of private ponding systems.
4. The City will continue to sweep paved public streets within the community at least one time
per year. Areas with direct discharge into wetlands, and rivers will be given first priority. In
addition, for future purchase or rental of street sweeping equipment, the City will give
consideration to utilizing street sweepers that are highly effective at removing nutrients from
the street.
5. The City will require that the allowable total phosphorus discharged to the Mississippi is
0.22 pounds/acre/year.
6. The City will develop and implement Best Management Practices (BMPs) at City public
works facilities and City owned lands to retain and prevent pollutants in stormwater runoff
from leaving the site.
7. The City will require individual sewage treatment systems to be in conformance with the
Washington County Individual Sewage Treatment Systems Regulations.
8. The City will eliminate known illicit (illegal) connections to the City’s Storm Water System.
The city will also cooperate on illicit connection removal efforts with Washington County.
9. The City will require the implementation of erosion and sediment control plans and best
management practices for construction and land development activities in accordance with
the developer’s Storm Water Pollution Prevention Plan (SWPPP) for construction activity
requirements as required by the MPCA.
10. For proposed land development adjacent to lakes and wetlands, the City will require native
plantings in vegetative buffer strips adjacent to the lake or wetland. The strips should be
planted with legumes or other perennial grasses as a means to limit erosion and nutrient
transport to the waterbody.
26
11. The City will protect wetlands within the community to assure that the wetland functions are
maintained and that the wetlands value in providing water quality benefits will not be
significantly impacted.
12. The City will continue implementation of the public education program to foster responsible
water quality management practices by City residents and businesses. The public
information will include proper lawn fertilizing and other lawn chemical use, disposal of
lawn waste, and disposal of solid, liquid, and household hazardous waste products. The city
will work to accomplish these tasks through partnerships with other organizations such as
WMO’s, City businesses, and private citizen groups.
13. The City will coordinate with the SWWD and Metropolitan Council on water quality
monitoring programs proposed within the community. In addition, the City will work with
the SWWD on taking the appropriate corrective action to existing and future water quality
problems.
C. Erosion and Sedimentation Control
Goal: To prevent erosion and sedimentation to the maximum reasonable extent.
Policies:
1. The City will require implementation of erosion and sediment control plans and best
management practices for construction and land development activities in accordance with
the developer’s approved SWPPP for construction activity requirements as required by the
MPCA. The City may obtain financial surety from the proposed project to assure
compliance.
2. The City will enforce the erosion and sediment control plan and best management practices
on construction sites to control erosion, soil loss, and sedimentation. Areas adjacent to
waterbodies and wetlands, or to have known high erosion potential will receive highest
priority.
3. Where new or increased discharges are proposed to open channels, the City will require that
the project design comply with the channel stability standards set be the SWWD.
27
4. The City will incorporate with State and Federal requirements for stormwater permits on
land alteration activities.
5. The City may prohibit work in areas having steep slopes and/or high erosion potential when
the impacts of significant erosion cannot be controlled or mitigated. A minimum buffer
width of 60 feet is required for new development along areas defined as a bluff or ravine
(slopes generally exceeding 15% along a watercourse). In addition, as part of the
development proposal, the City may require restrictive or preservation easements on areas
having steep slopes or high erosion potential.
6. The City will sweep paved streets within the community at least one-time per year. Areas
with direct discharge into wetlands and rivers will be given first priority.
7. The City will determine the feasibility and effectiveness of developing a nuisance ordinance
for controlling excessive erosion on construction sites and agricultural lands.
D. Wetlands
Goal: To protect wetlands in conformance with the requirements of the Minnesota Wetlands
Conservation Act and rules, and other State, Federal and Regional regulations.
Policies:
1. The City has accepted the Local Governmental Unit (LGU) responsibility for wetland
management and will manage these wetlands in conformance with the Minnesota Wetlands
Conservation Act (WCA) of 1991, its amendments and rules (MN Rules Chapter 8420).
2. The City will notify parties proposing land disturbing activities (i.e.: altering, dredging,
filling, and draining) in wetlands of possible permit requirements from the MDNR, MPCA,
US Army Corps of Engineers (COE) and South Washington Watershed District (SWWD).
3. The City will cooperate with the permitting programs of the MDNR, MPCA, USCOE and
SWWD for proposed activities within the jurisdictional wetlands.
28
4. The City will utilize available wetlands inventory information developed by the U.S. Fish
and Wildlife Service, the MDNR, the Metropolitan Mosquito Control District and the
SWWD to preliminarily identify the location of wetlands on properties where land alteration
is proposed.
5. The City will require a wetlands report identifying jurisdictional wetlands as part of the City
approval process for land development. If wetland encroachments are proposed with the
development, wetland values and impacts will be evaluated on a case-by-case basis in
accordance with the requirements of the WCA and rules. Wetland area replacement ratios
will comply with tests established in SWWD Wetland Plan.
6. The City will require pretreatment of stormwater runoff prior to discharge to a City
waterbody or wetland. Pretreatment methods shall include Best Management Practices
identified in the current MPCA Minnesota Stormwater Manual or equivalent performance
standards. The pretreatment standards for phosphorus shall be in accordance with those
established by the SWWD in its WMP.
7. The City will cooperate with interested private or governmental parties on wetland
restoration projects and may participate in the State’s wetland banking program if the City’s
interests are benefited.
8. The City will require placement of native, unmaintained buffer strips adjacent to wetlands to
limit erosion and nutrient transportation to the wetlands. The minimum buffer widths will
comply with the SWWD Wetland Buffer Standards. Buffer areas shall be identified by
permanent manholes, a minimum of one per lot or for each 300 feet of wetland edge.
9. Excavations in wetlands for purposes other than wildlife habitat improvement will comply
with sequencing requirements of the WCA.
10. The SWWD has synthesized and simplified its Draft Wetland Management Plan and
developed wetland standards in the SWWD WMP. The City hereby incorporates those this
SWMP.
29
11. The city will require the submittal of a report which identifies waters quantity plans into
wetlands and limit those flows to the standards set in the SWWD WMP.
E. Groundwater
Goal: To protect groundwaters by prudent management of surface waters.
Policies:
1. The City will cooperate with County and State agencies to inventory and seal abandoned
wells and notify its residents of State standards on well abandonment.
2. The City will require individual sewage treatment systems to be in conformance with
Washington County’s Individual Sewage Treatment System Regulations.
3. The City will include the significance of sensitive geologic areas, including karst features,
when making land use decisions, when reviewing development proposals, or when
proposing construction of stormwater facilities. Any activities that may have contamination
potential to these areas and features will be required to include protection measures.
4. The City will include the use of infiltration methods to promote groundwater recharge where
groundwater will not be significantly impacted by the land use or stormwater runoff.
5. The City will develop a spill response program for containment, neutralization and disposal
of spilled materials illegally discharged onto the ground or into stormwater facilities.
6. The City will adhere to policies established by the City’s Wellhead Protection Plan and
Washington County Groundwater Plan.
7. The City will eliminate known illicit (illegal) connections to the City’s Storm Water System.
The city will also cooperate with the illicit connection removal efforts of Washington
County.
F. Recreation, Fish and Wildlife
30
Goal: To protect and enhance recreational facilities, and fish and wildlife habitat.
Policies:
1. The City will support the efforts of Local, State, and Federal agencies promoting public
enjoyment, and the protection of fish, wildlife, and recreational resource values in the City.
2. The City will protect wetlands in accordance with the goals and policies of this plan.
3. The City will require native buffer zones around wetlands and ponding areas in new
developments and restrictive easements for areas adjacent to the City waterbodies and
streams.
4. The City will create natural habitat buffer zones adjacent to the waterbodies, wetlands, and
streams in City property and parks, where feasible.
5. The City will encourage its residents to retain existing wetlands, vegetation buffers, and
open spaces for the benefit of wildlife habitat.
6. The City will guide future land planning activities and encourage community development
actions to include agricultural preserves and to protect existing wooded areas.
G. Enhancement of Public Participation, Information and Education
Goal: To educate and inform the public on water resources management issues, and to
increase public participation in water management activities.
Policies:
1. The City will continue the current public education program to foster public participation in
responsible water quality management practices by residents and businesses. The public
education topics include: fertilizer use and the restrictions on phosphorus as per MN Statute
18C.60; lawn care and lawn chemical use; solid, liquid and household hazardous waste
disposal; and natural water resource systems and protection methods.
2. The City will coordinate public information and education programs with information and
activities from State and Federal agencies and the SWWD.
31
3. The City currently distributes water resource and water quality related information to
residents at least once annually. The City will also have water resource protection
information available at City Hall for review by its residents.
4. The City will have available for public review water resource and water quality information
at City Hall. The library will contain resources referenced in this SWMP, public
information on water quality practices and activities, The St. Paul Park MS4 Storm Water
Pollution Prevention Plan (SWPPP), and other water resource-related documents and
information.
5. The City will consider forming an Environmental Commission, or Advisory Committee to
address water resource-related public education and information, solicit public concerns and
issues, and develop further water resource management strategies as issues arise.
6. The City will utilize best management practices in the management of City lands,
recreational areas, and open space areas and public works facilities.
7. The City will require lawn care companies operating in the community to have phosphorus-
free fertilizer available for lawn applications and prohibit phosphorus to be used as fertilizer
unless if allowed under Minnesota Statute 18C.60.
8. The City will utilize the programs developed by the SWWD and WCD into local education
programs, including notifying residents and officials of educational opportunities, arising
programs on local cable television and distributing informational pamphlets.
32
SECTION IV – ASSESSMENT OF PROBLEMS AND CORRECTIVE ACTIONS This section contains an assessment of existing and potential water resource related problems presently
known within the City and a description of structural, non-structural, or programmatic solutions that could
be used to address or correct the problems. The problems and concerns have been identified by MFRA as
part of the land and water resource data collected in the preparation of this SWMP. Additional problems
and concerns may be included in this SWMP by City Staff at a later date. Some of the topics discussed
herein are repetitive because they are presented according to the State rules and outline for local
management plan preparation.
A. River and Surface Water Quality
1. Assessment:
a. The Mississippi River is listed as “Impaired” based on exceeding Turbidity standards for
aquatic life according to MPCA’s 2008 TMDL Report. The stretch of the Mississippi River
that is impaired includes land adjacent to the City.
b. There may be potential failing on-site sewage treatment systems adjacent to city wetlands,
waterbodies, bedrock layers, and streams.
c. The quality of surface water discharge is reduced due to erosion and sedimentation build-up
in stormwater quality ponds.
d. Run-off waters containing sediments are being discharged directly into lakes and City
waterbodies from roadway areas and storm sewer outfall pipes without prior pretreatment.
2. Corrective Action:
a. The City shall cooperate with the MPCA if an approved TMDL load allocation is
determined for the City; stringently uphold surface water quality and erosion/sediment
control standards for development within subwatersheds; consider joint preparation of a
Mississippi River water quality diagnostic feasibility study with the adjacent communities of
Newport and Inver Grove Heights.
33
b. The City shall continue to enforce on-site sewage system maintenance programs and
necessary upgrades with property ownership changes.
c. The city shall develop and implement a stormwater facility inspection and maintenance
plan.
d. The City shall stringently uphold erosion control standards for land development and house
building activities; prioritize or increase frequency of street sweeping for areas draining
directly into City waterbodies; require new storm sewer outfalls to incorporate stormwater
treatment prior to discharge where feasible; incorporate stormwater treatment in system
upgrade projects where feasible; regularly maintain and clean storm sewer ponding and
piping facilities; dredge and dispose of sediment debris at storm sewer outlets; construct
natural or structural sediment control buffers at the end of roadways draining into
waterbodies; encourage design of new impervious surfaces to channel through pervious
surfaces before reaching a catch basin, or other storm sewer inlet.
B. Flooding and Rate Control Issues 1. Assessment:
a. Based on 100-year 24-hour storm event modeling, there are several areas located within the
Downtown and City-South Subwatersheds (DT-4,5,6, CS-3,4,8,9) that are shown to pond
water due to the storm sewer lines backing up. In the event stormwater does back up in
those areas, there would be potential for property damage due to flooding.
b. In the southern part of the city, there are currently no storm sewer lines to serve the general
area that runs south of 14th Avenue from 2nd to 7th Streets. During significant rain events,
this area will flood at the low points and it may take days for the floodwaters to subside.
There are several homes in the area that may be damaged as a result of flooding.
c. In the northeast part of the city, there is a potential flooding problem in the area of Hastings
Avenue where it intersects the Burlington Northern railroad line. Several businesses located
near the area may be at risk due to flooding or washed out roads.
34
d. There may be flooding caused by the receiving storm sewer inlet either being plugged by
debris, or the outlets hydraulic grade line being at or near the receiving inlet’s opening
elevation.
e. Landlocked drainage districts that contain ponding areas without structural outlets are
shown to pond to elevations higher than shown for the 100-year 24-hour storm event. Some
drainage districts are shown to have the 100-year, 10-day HWL's cover a large portion of the
district.
f. In addition to all corrective actions stated, the City will work with the SWWD on taking the
appropriate corrective action to existing and future water quality problems.
2. Corrective Action:
a. The City shall insure that any new construction that takes place in upstream sub districts
conforms to existing flow-rates or lower. The City will provide overflow outlets on the
trunk line as the line approaches the open ditches adjacent to the railroad and then use the
ditches for flow-relief. Consult with homeowners and businesses where on-site runoff
drains to these lines and investigate possible methods on reducing direct runoff into the
storm system (i.e. rain barrels, rainwater gardens, grassed swales, etc.). The City will make
improvements to the trunk line whenever reconstruction is taking place in the affected
drainage districts.
b. The City shall insure that any new construction taking place shall conform to existing flow-
rates or lower. Any new impervious surfaces created shall first travel through grassed
surfaces before reaching the streets, particularly if the street is shown to drain at or near the
low areas. The City shall consider adding storm sewer to serve this area if improvements to
the sewer and/or street systems are planned. Consult with homeowners and businesses
where on-site runoff drains to these lines and investigate possible methods on reducing
direct runoff into the storm system (i.e. rain barrels, rainwater gardens, grassed swales, etc.).
c. The City shall maintain the ditch located along the Soo Line Railroad free from
obstructions. Ensure the culvert that crosses the Soo Line Railroad and eventually drains to
Hastings Avenue has a defined flow-path and does not encroach any adjacent buildings. If
any improvements are made to Hastings Avenue, the wetland area may need to be dredged
35
to provide more flood storage and the overflow may need to be lowered to ensure that
ponding of water will not encroach the roadway. Upstream development shall be limited to
pre-development rates or lower.
d. The City will verify that all storm sewer inlets are free from obstructions on a yearly basis.
The City should further investigate the developed model and determine additional areas
where overland flooding may be a concern for exiting building openings.
e. The City will provide positive outlets for the landlocked areas where structures are or are
shown be impacted by snowmelt or large runoff events. The outlets shall be designed so
downstream properties will not be significantly impacted. If development is scheduled to
occur in any portion of the landlocked district, volume controls shall be considered. The
volume of runoff in the development must be shown not to increase if receiving area
downstream is landlocked and not capable of accommodating the increased volume of
runoff. If structural outlets can not be feasibly constructed within the development, a
calculation shall be evaluated to show lowest building openings built at least 1.5 feet above
the 100-year, 10-day runoff HWL elevation.
f. In addition to all corrective actions stated, the City will work with the SWWD on taking the
appropriate corrective action to existing and future flooding problems.
C. Impacts of Water Quantity or Quality Management Practices on Recreational
Opportunities 1. Assessment:
a. Existing land use activities and land development within the City may adversely impact
water related recreational activities in City waterbodies.
2. Corrective Action:
a. Water related recreational activities will be considered in land use decisions and in
reviewing land development proposals.
36
b. Future park and trails will retain the natural character of waterbodies and watercourses
within the community and trails will be designed to encourage water related recreational
opportunities.
c. The City’s stormwater management practices and the implementation of erosion and
sediment control practices will maintain and improve water quality in the City’s waterbodies
increasing their value as recreational resources.
D. Impacts of Stormwater Quality on Fish and Wildlife Resources 1. Assessment:
a. Sediment, nutrients and urban pollutants in untreated stormwater discharges adversely
impacts water quality and fish and wildlife resources.
b. Manicured lawns immediately adjacent to lakes and wetlands allow lawn chemicals to
runoff directly into waterbodies and also encourages habitation of lawns by Canada geese
with the resulting deposition of waterfowl waste.
2. Corrective Action:
a. Stormwater discharges will be pre-treated prior to release into City waterbodies and
wetlands, where feasible.
b. A natural, unmaintained buffer zone will be required around natural or constructed
waterbodies as part of future development proposals and buffer zones will be encouraged
around all waterbodies, wetlands and watercourses.
c. In addition to all corrective actions stated, the City will work with the SWWD on taking the
appropriate corrective action to existing and future natural resource problems.
E. Impacts of Soil Erosion on Water Quality and Quantity 1. Assessment:
37
a. Construction-related soil erosion can occur on small and large-scale construction projects.
Sediment can be discharged off-site or into City waterbodies by direct runoff or by
construction equipment tracking sediment off-site.
b. Erosion of steep slopes due to natural causes or construction activities can adversely impact
waterbodies or watercourses.
2. Corrective Actions:
a. Erosion and sediment control plans will be prepared, implemented, and enforced on
construction projects to prevent erosion, sedimentation and adverse water quality impacts.
b. Existing eroded steep slopes will be addressed and corrected as part of development
proposals. Development within steep slopes will be discouraged unless adverse impacts can
be property mitigated.
F. General Impact of Land Use Practices, and in Particular, Land Development and Wetland Alternation on Water Quality and Water Quantity
1. Assessment: a. Land use practices, land development and wetland alterations may have a significant
impact on water quality and water quantity. Impervious surfaces are often the receiving
source of urban pollutants and contribute more runoff volume than natural land and
vegetation. Increased development in the City has the potential to increase downstream
flooding and degrade water quality.
b. Land development in adjacent communities has increased the flooding potential within the
City and future land development in St. Paul Park, without proper planning, may increase
the flooding potential in neighboring communities.
2. Corrective Actions:
a. Implementation of the stormwater management practices within this SWMP will address
potential negative impacts of land development. The City will work with new development
38
proposals to remedy existing drainage problems, where feasible. Implementation and
enforcement of erosion control best management practices will protect the quality of surface
waters. In addition, the City will also continue to monitor lot coverage amounts for newly
developing areas.
b. Better communications and cooperation with adjacent communities and the WMO’s will
reduce unanticipated impacts of land development impacting other communities and
improve joint water resource planning and improvement efforts.
G. Adequacy of Existing Regulatory Controls to Manage or Mitigate Adverse Impacts on Public Waters and Wetlands 1. Assessment:
a. Public waters and wetlands are currently regulated by programs administered by the
USCOE, MDNR and by Minnesota’s Wetland Conservation Act (WCA). The City has
accepted the responsibility of the Local Government Unit (LGU) and currently administers
the WCA requirements.
2. Corrective Action:
a. It is the City’s position that the existing regulatory programs and the implementation of this
SWMP will adequately manage or mitigate adverse impacts on public waters and wetlands.
H. Adequacy of Programs to Limit Soil Erosion and Water Quality Degradation 1. Assessment:
a. As part of the land development or alteration, the City requires the qualified preparation of
stormwater management plans which include erosion and sediment control plans to address
temporary and permanent water quantity and quality issues and erosion concerns.
Sometimes, stormwater management facilities are not fully constructed. In other cases,
erosion control practices are not implemented or maintained. These shortcomings result in
the project potentially not meeting design standards and soil erosion standards. This may
result in the degradation of water quality.
2. Corrective Action:
39
a. The City will improve its current enforcement program and require verification that
permanent stormwater management facilities have been constructed in accordance with the
approved plans. The City will also consider preparation of a soil erosion nuisance ordinance
with enforcement and penalty clauses.
I. Adequacy of Existing Programs to Maintain the Tangible and Intrinsic Values of Natural Storage and Retention Systems
1. Assessment:
a. There is a varied and diverse wildlife in City waterbodies. Land use activities and future
land development have the potential to reduce recreational and wildlife opportunities and the
natural values of the City waterbodies.
2. Corrective Action:
a. It is the City’s position that the existing State, Federal and Local regulatory controls will
maintain the tangible and intrinsic values of City waterbodies.
The City will maintain flood storage volumes below 100-year flood plain elevations on all
waterbodies, obtain easements, where feasible, below floodplain elevations for the
protection and maintenance of the waterbodies and require natural buffer zones adjacent to
City waterbodies on future development proposals.
The City may consider future water quality analysis or diagnostic feasibility studies of City
ponds to further determine conditions of the waterbodies, potential expanded uses, and long-
term impacts of existing or future land activities.
J. Adequacy of Capital Improvements Program to Correct Problems Related to Water Quality, Water Quantity Management, Fish and Wildlife Habitat, Public Waters and Wetland Management, and Recreational Opportunities.
1. Assessment:
a. In the near future, the city will be updating its Capital Improvements Plan (CIP) to further
identify and prioritize capital improvements needed within the community. The CIP will
40
also likely identify funding sources for the improvements. Currently the City has a
stormwater utility fund, which generates revenues to fund stormwater management projects,
and programs deemed by the City to be in the public’s best interest. The CIP will likely
identify a higher number of stormwater-related than can be funded through the current
stormwater utility fund.
2. Corrective Action:
a. The City will identify and prioritize stormwater-related improvements in the CIP and
additional methods of project financing. In addition, the City will need to address a variety
of water quality and quantity issues in conjunction with land development proposals or City
street improvement projects, when feasible.
K. Future Potential Problems Anticipated to Occur Within Next 20 Years Based on Growth Projections and Planned Urbanization 1. Assessment:
The 2008 Comprehensive Plan identifies staged growth areas within the City to the year 2030.
Projected urbanization is mainly in the vicinity of West Bluff and Grey Cloud Island
Subwatersheds, and along the western edge of the Downtown and City-South Subwatersheds. The
following are potential stormwater related problems and issues anticipated to occur from
urbanization.
a. General – Urbanization with added areas of impervious surfaces has the potential to
decrease water quality and increase flooding potential both during construction and after
development is complete. During construction, erosion and sedimentation can degrade
water quality and in the longer-term, additional phosphorus and other pollutants may be
discharged to waterbodies due to urbanization.
b. Roadways – Public or private roads in the City have the potential to degrade water quality
by roadway erosion, insufficient culvert size or length, and road encroachment into
wetlands.
41
c. Pond and Stormwater Maintenance – Urbanization will increase the number of public and
private stormwater ponding and drainage facilities. For the facilities to adequately and
effectively function, routine inspection and maintenance will be required. City and private
funds will need to be expended for stormwater-related inspections and maintenance.
d. Minor Storm Sewer and Water Quality Improvements – It is anticipated that there will be
increased public pressure to address minor storm sewer or drainage problems and water
quality issues within the City. The projects are often difficult to fund and to obtain wide
community support due to perceived limited benefit.
2. Corrective Action:
a. General – To maintain water quality and protect against flooding, urbanization will follow
an orderly process of site evaluation, design and project construction. Construction
activities will need to include erosion control practices and site development will need to
incorporate proper stormwater ponding and storm drainage facilities for the control of
surface waters.
b. Roadways – Public or private road maintenance and improvement projects will address
stormwater quantity and quality issues such as wetland protection, slope stabilization,
culvert capacity, erosion and pretreatment of stormwater, where feasible.
c. Pond and Storm Sewer Maintenance – A city-wide pond and storm sewer maintenance
program is implemented (per MS4 Phase II requirements) and funded to regularly inspect,
clean, and maintain public stormwater facilities. For private stormwater facilities,
maintenance agreements should be established identifying maintenance programs,
responsible parties, and consequences for non-compliance.
d. Minor Storm Sewer and Water Quality Improvements – Minor stormwater-related
improvements should be identified and prioritized. A funding method should be established
and a process determined for implementing these projects.
42
SECTION V – IMPLEMENTATION PROGRAM This section identifies the various methods, programs and official controls available to the City for the
implementation of this SWMP. Many of these items are already in place, and currently utilized by the City.
A. City Regulatory Controls The City has various regulatory controls to manage and protect water resources and reduce stormwater-
related impacts in the community. The following presents each of the official controls:
River District Ordinance
The City has adopted an ordinance for areas located adjacent to the Mississippi River Shoreland in
the Critical Area as defined by Executive Order 79-19.
Floodplain District Ordinance
The City has adopted a Floodplain District Ordinance.
Wetland Regulation
The City has accepted the responsibility of the Local Governmental Unit (LGU) under the
Minnesota Wetlands Conservation Act and will review wetland impacts in accordance with the
State wetland law and rules.
Subdivision Ordinance
The City has adopted a Subdivision Ordinance controlling the land use and development of property
within the community. In addition to other items, the ordinance addresses City project review and
approvals, development of steep slopes, the necessity of erosion and sediment control plans, design
standards for stormwater facilities and required flowage and drainage easements.
Stormwater Management and Erosion Control Plans
The City will assume responsibility for this permitting and require development and land activities
to comply with City standards that meet or exceed MPCA and NPDES requirements and are
consistent with SWWD rules.
43
Floodplain Alteration
The City will assume responsibility for this permitting and require development and land activities
to comply with the adopted Floodplain District Ordinance.
Wetland Protection
The City has previously accepted the responsibility as the Local Governmental Unit under the
Minnesota Wetland Conservation Act (WCA) and will continue as the permitting authority for
wetlands protection in conformance with the State WCA laws and rules.
Dredging
The City will not assume responsibility for permitting this activity. The permitting responsibility
will be retained by State and Federal agencies.
Shoreland and Streambank Improvements
The City will not assume responsibility for permitting this activity. The permitting responsibility
will be retained by the State and Federal agencies.
B. Management Programs The City will implement the following water resource-related management protection programs.
Buffer Requirements
The City will require natural, unmaintained wetland buffers around lakes, wetlands and waterways
in development proposals. In addition, the City will begin the placement of natural buffers around
all City waterbodies.
Best Management Practices
The City will sweep paved public streets at least one-time per year with highest priority given to
streets draining directly to waterbodies.
1. The City currently implements a public stormwater facility inspections and maintenance
plan per NPDES MS4 requirements and will require similar plans for private stormwater
systems.
44
Public Education
The City will prepare and implement a public education program to foster sound water resource
protection practices within the community and to develop additional strategies necessary to protect
the City’s water related amenities.
Water Quality Monitoring
The City will support efforts of the Metropolitan Council, Washington Conservation District,
SWWD, and other agencies collecting water samples in the City.
C. Stormwater Design and Performance Standards The following design and performance standards will assist in proper stormwater management, reduce
flooding impacts and help in the planning for urban development.
Maximum Flowrates
1. General Standards - Maximum stormwater discharge rates will be controlled on a
subwatershed district basis and subdistrict basis to not exceed the existing runoff rates for
the 2, 10 and 100 year 24-duration rainfall event and the predevelopment infiltration
capacity of the site must be maintained.
2. Exception - Subwatershed district or subdistrict discharges may exceed existing conditions
provided the stormwater conveyance system in the downstream district is adequate to
convey the additional discharges.
3. Roadway culverts - During roadway maintenance operations or improvements, subdistrict
outlet culverts will be sized to accommodate identified discharge flowrates and be at least
18-inches in diameter.
Ponding Facilities
If stormwater ponding facilities are proposed, all facilities shall be designed and constructed to meet
water quantity and water quality requirements of this SWMP. Detention ponds shall be designed
for the 100-year critical storm event with multi-staged outlets to control the 5-year and 100-year
storm events. Private water quality ponds shall meet the MPCA’s recommendations or equivalent
45
performance standards. Storm water ponds shall include a skimmer, where feasible, to remove oils
and other floating pollutants. Additional pond design standards are provided in Section VII.
Stormwater Conveyance Systems
Trunk storm sewer and conveyance systems downstream of ponds or other stormwater storage areas
shall be capable of conveying the 100-year storm event discharge from the storage facility. Lateral
storm sewers within site developments shall be designed for the 5-year storm event. Roadways
culverts shall be designed to convey the 25-year storm event with a minimum of 1-feet of freeboard
between the street and surcharged culvert high water level. Natural drainage ways used for trunk or
lateral storm drainage shall be bio-engineered or structurally armored to prevent erosion.
Floodplain Standards and Minimum Building Floor Elevations
Storage volumes below flood plains and projected 100-year high water levels shall be maintained.
Fill which displaces storage volumes below flood plains, if allowed, shall be mitigated elsewhere on
the same waterbody. Fill and excavated areas below the floodplain shall be protected against
erosion. Buildings adjacent to waterbodies shall be constructed with a minimum floor elevation of
3 feet above the projected high water level or MDNR established OHW, whichever elevation is
highest. The City may allow a minimum separation of 2-feet between the lowest building elevation
and high-water level if the high-water elevation is well established.
Incorporation of Additional Stormwater Best Management Practices
The city will use alternative BMP’s in place of, or in addition to, stormwater ponds where feasible.
The BMP’s will be based on MPCA design standards and will be subject to the same flood-
protection requirements as stormwater ponds. Additional alternative BMP design standards are
presented in Section VII.
D. Capital Improvements Program The City has reviewed its Capital Improvements Plan (CIP) to identify and prioritize necessary
improvements within the community. Currently the CIP is funded by the general fund and through the City
Storm Water Utility. Future capital improvements funded by the City will be at the direction of the City
and based upon project feasibility, City priority, and availability of financial resources. Privately installed
improvements will be consistent with the management strategies identified in this section.
46
The SWWD is in the process of developing a Coordinated Capital Improvement Program that will be used
to provide funding assistance to cities. The City will work with the SWWD in the process.
E. MS4 Phase II Storm Water Pollution Prevention Program The MPCA has issued permit coverage to the City to discharge stormwater as defined in the MS4 Phase II
SWPPP permit (MN040000). The intent of the NPDES Phase II Program is to get municipalities to reduce
or control the amount of storm water runoff, both in the form of water quality, rate control. Another key
component is to educate businesses and public about proper stormwater management. The program is
comprised of six minimum control measures (MCM’s). Those measures are:
• Public education and outreach
• Public participation/involvement
• Illicit discharge, detection, and elimination
• Construction site runoff control
• Post-construction site runoff control
• Pollution prevention/good housekeeping
To obtain the MS4 permit coverage, the city has generated a stormwater pollution prevention plan
(SWPPP) that contains best management practices (BMP’s) for each MCM. These MCM’S must have
attainable goals for each BMP. BMP’s are defined by the MPCA as “schedules of activities, prohibition of
practices to prevent or reduce the pollution of waters of the state.” The current Phase II permit (MN R
040000) is available online to view and is located on the MPCA website. The web address is
www.pca.state.mn.us/water/stormwater/stormwater-ms4.html. The website also contains additional
information on the MS4 Phase II program including guidance and further explanations.
The City has submitted yearly annual reports showing compliance to permit requirements. The current
permit will be in effect until 2011. At that time, the MPCA will re-issue the permit for a period of five
years. The City SWPPP is available for review at the City offices.
F. Measures of Success
The City will incorporate SWWD’s Annual evaluation tool for District activities (Table 5.3, Pg. 88) as a
success measure to strengthen cooperation between the City and SWWD.
47
SECTION VI – IMPLEMENTATION PRIORITIES AND FINANCIAL CONSIDERATIONS A. Implementation Priorities This SWMP has presented an implementation program identifying those various regulatory controls,
management programs and potential capital improvements that are necessary to address City surface water
resource related needs and funding capabilities. Table 4 below prioritizes the implementation program. It
is the City’s position that regulatory controls and management programs will be effective once this SWMP
is adopted by the City Council. Capital improvements will need to be implemented and funded by private
parties or the City based upon City growth, demand and available resources.
Table 4. Implementation Program Priorities Ranking Implementation Program Description
1 Adequate planning and engineering review of all new development or redevelopment sites and roadway improvements for conformance with goals, policies and management objectives of this SWMP.
2 Inspection and enforcement of erosion control measures for site development
and agricultural land uses. 3 Inspection of stormwater facilities and providing adequate maintenance as
required. 4 Acquire easements for ponding areas, stormwater facilities, and for access to
outlet control structures. 5 Continued implementation of the public information and education plan. 6 Construct or require construction of capital improvements to address those
stormwater related problems anticipated due to future City growth and urbanization.
48
B. Financial Considerations Implementing this SWMP will have financial impacts on the City. The paragraphs below describe the
implementation item and the anticipated cost of the associated regulatory control or management program.
These are not necessarily new costs to be budgeted by the City since many of these costs are already being
charged back to developments or included within current City programs. The anticipated costs of capital
improvements are included in this SWMP. The subsection to follow identifies estimated funding the City
requires to implement these programs and future capital improvements.
1. The City will review site plans and other proposed projects for conformance with this
SWMP. The estimated cost for this item is $5,000-10,000 per year. These costs will
generally be recouped from new developments.
2. The City will inspect and enforce erosion control measures identified in this SWMP. The
estimated cost for inspection is $15,000-20,000 per year. Permit fees associated with
building activities will recover portions of these costs.
3. The City will inspect municipal stormwater basins, ponds and outfalls every other year at a
minimum. The City will also inspect all structural pollution control devices every year.
Structural Devices include trap manholes, sump manholes, floatable skimmers and traps,
and separators. The estimated cost for this task is $5,000-7,000 per year.
4. Acquisition of easements around ponding areas, stormwater facilities or for access to outlet
control structures will be identified during the City project review process. Some easements
can potentially be obtained during the project review process. The additional cost for this
item will vary greatly based on project approval conditions and the value and use of
property within the easement areas.
5. Funding needed to provide the public information and education plan. The plan is part of
NPDES Phase II requirements. The estimated cost to provide education mailings is $1,000
to $5,000 per year. The City will work to share educational resources with other concerned
parties such as the Washington Conservation District, watershed districts and other parties
concerned with storm water management.
49
6. Construction of capital improvements addressing known surface water resource problem
areas or anticipated problems due to urbanization and growth will require detailed
engineering feasibility studies, construction documents and property easements. The
specific improvements will need to be determined based on need, cost and availability of
funds.
C. Funding Sources The City currently uses general tax revenues, special assessments and the Storm Water Utility fee to fund
program and capital improvements identified in this SWMP. While general tax revenues and the Storm
Water Utility can likely fund the regulatory and management programs, special assessments will generally
be required to fund the larger capital improvements projects.
Several other revenue sources available to the City including the establishment of a watershed management
tax district under Minnesota Statute 103B.245. The watershed management tax may arrive by authority of
the SWWD. The City will need to review each of these potential funding sources and determine the most
appropriate and acceptable course of action for each program or project.
In addition to the local sources, the SWWD is developing a Coordinated Capital Improvement Program that
will include funding assistance to help cities implement local CIPs.
50
SECTION VII – STORMWATER MANAGEMENT PLAN AND EROSION CONTROL STANDARDS All new construction or redevelopment projects with land disruption over 1.0 acres will be required to
prepare and submit for City review a stormwater management plan and erosion control plan meeting the
following standards. All construction sites regardless of size will be required to provide and maintain
minimum erosion control measures during construction.
Stormwater Management Plan Standards:
1. The rate of runoff from the developed or redeveloped site shall not exceed existing runoff rates for
the 2, 10 and 100 year 24-hour rainfall events. The predevelopment infiltration capacity of the site
must be maintained.
If post development discharges from sites are being compared to the peak direct discharges
identified in this SWMP, the NRCS (formerly SCS) Curve Numbers used for the site’s drainage
analysis shall reference the chart entitled “General Land Use Curve Numbers for Developed Sites”
(see Table 2)as provided in Appendix G. Predevelopment CNs shall not be greater than 62 when
modeling.
2. All proposed stormwater best management practices (BMP’s) shall be required to maintain or
improve stormwater quality prior to discharge from the site. BMP’s shall be designed in
accordance with MPCA Permanent Storm Water Management System standards or equivalent
performance standards. The maximum expected benefits for BMPs should conform to the standards
shown in Table 2.4 of the SWWD Standards Manual (Pg. 27). The overall stormwater management
plan shall be designed to remove 80% total suspended solids (TSS) in the stormwater discharge on
an average annual basis. The City will require that the allowable total phosphorus discharged to the
Mississippi is 0.22 pounds/acre/year. The Walker P8 model is the preferred model to demonstrate
TSS and TP removals.
3. All ponding facilities (wet detention basins, dry ponds, infiltration basins) shall provide easement
areas for future access, vegetative buffers and prevention of future encroachments or filling.
Ponding outlets shall include skimmer devices (wet detention basins only), where feasible, to
51
remove oils and other pollutants. Skimmer device inlets must be placed at least 1 foot below the
treatment pond’s established NWL.
4. The volume of site runoff may not increase due to the proposed project when the receiving area
downstream is landlocked and not capable of accommodating the increased volume of runoff. In
landlocked areas, the City will encourage construction of a stormwater outlet system and will
require easements around ponded water areas and the downstream conveyance systems. A 100-
year, 10-day runoff event (7.2 in.) shall be used to determine flood impact to any landlocked area
when no outlet can feasibly be provided.
5. Runoff draining onto a site must be accommodated in the analysis and design of new stormwater
management facilities.
6. Downstream stormwater impacts due to development shall be addressed with development
proposals. Impacts due to water quantity (flow rates and volumes) and water quality shall be
identified and appropriate mitigation measures incorporated.
7. The lowest floor of new buildings shall be constructed a minimum of 3 feet above the projected
100-year high-water elevation or MDNR OHW (whichever is higher) of nearby surface waterbodies
or stormwater ponds. The City will consider allowing a minimum of 2 feet separation where high-
water conditions are well established. Emergency overflows shall be at least 1.5 feet below any
adjacent building openings in other low areas (i.e. street low points, backyard low points) that do
not have an established 100-year high-water elevation, or in low points served by storm sewer that
is normally dry after storm events. Emergency overflows shall be provided and identified on plans
to protect structures against flooding.
8. There shall be no encroachment upon the floodway (main flowage channel) of the FEMA
established 100-year floodplain. Encroachment into a 100-year floodplain is discouraged but will
be allowed if compensatory floodplain storage is provided in the same waterbody or drainage
district and the filled area and excavated areas are properly protected against erosion.
9. Stormwater design analysis shall utilize an industry standard hydrograph, routing method and time
of concentration determination. Storm sewer lateral systems for individual sites shall be analyzed
52
utilizing the rational method. Stormwater ponding areas and downstream conveyance systems shall
be designed for the 100-year, 24-hour storm event with a multi-staged outlet to control the 5 and
100-year events to pre-development levels. Lateral storm sewers shall be designed to accommodate
the 5-year storm event. Runoff “C” values and IDF curves used for the rational method shall be in
accordance with MNDOT Drainage Manual Dated September 27, 2005 as revised herein.
10. If “infiltration basins” are intended to be used as a BMP, the owner or developer shall conform to
the Infiltration Basin Evaluation Guidelines as shown in Appendix J for each basin. The basin or
basins will be required to comply to all MPCA and SWWD standards regarding
infiltration/filtration and will be subject to approval by the City Engineer. BMP’s considered
“infiltration basins” include:
• infiltration basins • rainwater gardens • sand filters
• organic filters • bioretention areas • enhanced swales
• dry storage ponds
with underdrain
discharge
• off-line retention
areas
• natural
depressions
When plans are approved, the developer owner must provide a maintenance agreement for each
basin constructed. The City will not maintain private infiltration basins.
11. Alternative stormwater best management practices will be allowed where practicable and feasible.
Each individual BMP downstream conveyance system shall be designed for the 100-year, 24-hour
storm event and at the point of ultimate discharge, the flow-rates must be below existing conditions
for the 5 and 100-year events. The alternative BMP’s must also have emergency overflows
provided. The BMP or the series of BMP’s must show treatment levels that meet or exceed MPCA
standards, provide 80%TSS and 50%TP removal on an average annual basis and must use
acceptable engineering methods. Once approved by the City, the developer must provide a copy of
the MPCA Storm Water Permit pertaining to the Permanent Storm Water Management System
before construction can begin.
12. The City recommends the use of the Metropolitan Council’s “Minnesota Urban Small Sites BMP
Manual” and the MPCA ”Minnesota Stormwater Manual” as sources for selecting and designing
the applicable management practice or practices.
53
13. Redevelopment projects requiring MPCA Construction Permit (MNR100001) coverage are required
to remove 80% on an average annual basis for the additional impervious surfaces when compared to
existing conditions for the affected parcel(s). The City will require that the allowable total
phosphorus discharged to the Mississippi is 0.22 pounds/acre/year.
Erosion Control Standards
1. Proposed erosion control plans shall show location and type of all temporary and permanent erosion
control BMP’s on the plan. Detail plates shall be provided for all structural BMP’s that are used for
either temporary or permanent erosion control.
2. The plan shall show proposed methods of retaining waterborne sediments on-site during the
construction period and proposed restoration, covering or re-vegetation after construction.
3. The plan shall show locations of any temporary sediment basin(s). Temporary Sedimentation
Basins shall be designed in accordance with Part III.B of the MPCA “Storm Water Discharge
associated with Construction Activity” (MN R100001) permit.
4. Sites with high erosion potential characterized by steep slopes or erodible soil will be required to
provide site-specific construction recommendations by a Soils Engineer for City review. Steep
slopes shall be defined as areas of 12% or more slope. In addition, a financial surety may be
required to ensure performance.
5. If work is being done inside the “Critical Areas” as defined by the MNRRA, the plan shall show no
proposed grading in areas equal to or greater than 18% slope.
6. If “infiltration basins” are proposed for the construction site, a note must appear on the plan stating;
“The infiltration basin area(s) cannot be used to treat construction site runoff, and shall not be
constructed to final grade until the contributing drainage area achieves final stabilization and
approved by the City Engineer or the City Engineer’s authorized designee.” In addition, the
following statement shall also appear; “The proposed infiltration basins shall be roped off as not to
allow heavy construction site traffic to enter any basin and the basins shall be staked off before any
construction can begin.”
54
7. If any disturbed soil is located within 200 lineal feet of a “surface water” as defined by the MPCA,
and the area has a continual positive slope to the “surface water”, the exposed area must provide
temporary erosion protection, or permanent cover according to Part IV.B.3 of the MPCA MN
R100001 Permit. Those areas requiring temporary erosion protection or permanent cover shall be
identified on the plans.
8. All sediment control practices shall be installed according to Part IV.C of the MPCA MN R100001
Permit.
9. The erosion control plan shall provide rock construction entrances for all entrances where heavy
construction traffic will enter. Those entrances must be clearly identified on the plan.
10. Proposed design, suggested location and phased implementation of effective, practicable erosion
control measures for plans shall be designed, engineered and implemented to achieve the following
results:
a. Prevent gully and bank erosion: and,
b. Limit total off-site permissible annual aggregate soil loss for exposed areas resulting from
sheet and rill erosion to an annual, cumulative soil loss rate not to exceed 7.5 tons per acre
annually.
11. The City shall receive documentation that the NPDES General Storm Water Permit for Construction
Activity application has been approved from the MPCA, as well as any other approved applications,
as required, for the construction site, such as the Subdivision Registration form, Permit
Transfer/Modification form, and the Notice of Termination form.
55
SECTION VIII – AMENDMENT PROCEDURES It is the City’s intention to have this SWMP reviewed and approved by the Met Council in accordance with
Minnesota Statutes, Section 103B.235. After approval, it will be adopted by the City Council and
incorporated into the City’s Water Resource Library.
This SWMP has been prepared to extend through the year 2019. The SWMP may need to be updated to
conform with the SWWD watershed plan and this SWMP may need to be updated for conformance with
the Washington County Groundwater Plan.
If the City proposes changes to this SWMP before year 2020, the changes and their impacts will be
determined by the City as either a “minor” change or a “major” change. The general descriptions of minor
or major changes and the associated reviewal and approval requirements are presented as follows:
Minor Changes would include small adjustments to subwatershed district or subdistrict boundaries or other
minor changes that would not significantly affect the rate or quality of stormwater runoff discharged across
the municipal boundary or significantly affect high-water levels within the City. Minor changes also
include revisions made to the stormwater related Capital Improvements Program to best meet the City’s
water resource needs and financial considerations. For proposed minor changes, the City will prepare a
document, which defines the change and includes information on the scope and impacts of the change. The
document will be forwarded to SWWD for their records. The minor change will be implemented after the
document is adopted by the City Council.
Major Changes are those that could have significant impacts on the rates, volumes, water qualities and
water levels of stormwater runoff within the City or across its municipal boundaries. For proposed major
changes, the City will prepare a document, which defines the change and includes information on the scope
and impacts of the change. The document will be forwarded to SWWD for their review and approval.
SWWD shall have 60 days to comment on the proposed revisions. Failure to respond within 60 days will
constitute approval. After SWWD approval, the City will adopt the amendment as part of the SWMP.
