Minnehaha Creek Watershed District 30 Years of Water Resources Management

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2 Page 2 The year 1997 marks the 30th year of the Minnehaha Creek Watershed District (MCWD). The MCWD is one of the largest watershed districts in the Twin Cities metropolitan area. The District covers an area of 181 square miles in Hennepin and Carver Counties. The watershed extends 29 miles from St. Bonifacius in western Hennepin County to the Mississippi River in Minneapolis and includes all or portions of 30 communities. There are 109 lakes, eight major creeks, and thousands of wetlands. Important water resources located within the district include Minnetonka, Minnehaha Creek, the Minneapolis Chain of s, and Minnehaha Falls. The District is managed by a seven-member Board of Managers appointed by Hennepin County (6) and Carver County (1). The District has been a leader in planning and implementing water management projects and policies to improve water quality and reduce flooding. Major studies, projects, activities, and accomplishments over the past 30-years are highlighted in this booklet. Establishment of the MCWD (1967) The was established in 1967 under the authority of the state legislature at the request of the Hennepin County Board of Commissioners. The petition filed by the County in 1966 sought establishment of the district to conserve the waters and natural resources of the watershed. Their goals included improving lakes, marshes and channels for water storage, drainage, recreation and other public purposes. The County also wanted to develop projects to reduce flooding, to keep silt out of streams, and to control erosion of land. Other goals were reclaiming wetlands, controlling stormwater, and preserving water quality within the District s lakes and streams. Minnehaha Creek Watershed District Holy Name INDEPENDENCE 110 MAPLE PLAIN Katrina 12 LONG LAKE Wolsfied Long Mooney PLYMOUTH 101 Dutch Langdon 110 WATERTOWN ST. BONIFACIUS MINNETRISTA Mud SPRING PARK MOUND MCWD OFFICE Upper Minnetonka Gleason WAYZATA ORONO 15 Gray's Bay Dam WOODLAND Lower Minnetonka DEEPHAVEN TONKA BAY GREENWOOD 7 EXCELSIOR Christmas Virginia MINNETONKA GOLDEN VALLEY Brownie of the Isles Twin s 169 ST. LOUIS Cedar PARK Bass 7 Calhoun 100 HOPKINS Harriet Minnehaha Creek EDINA W MINNEAPOLIS Hiawatha Nokomis Minnehaha Falls Mississippi River Stone Parley Zumbra VICTORIA Shultz Minnewashta Lunsten Auburn Steiger CHANHASSEN 5 LAKETOWN Wasserman Pierson CARVER CO. HENNEPIN CO W RICHFIELD Marsh

3 Page Permit Applications Regulatory Program (1967-Present) A regulatory program was initiated in 1967 to mitigate the impacts of new land development and other projects on water resources within the District. Through the regulatory program, the District has reviewed and approved stormwater management plans and shaped projects in floodplains and wetlands. The regulatory program has also covered dredging, stream and lake crossings, and shoreline improvement projects. To date, the District has issued over 2,000 permits. Rule B: Stormwater Management Plans Rule C: Floodplain Alteration Rule D: Wetland Protection Rule E: Dredging Rule F: Shoreline and Streambank Improvements Rule G: Stream & Crossings Rule I: Variances Rule K: Dredging Contractor License Rule K: Performance Bond or Letter of Credit Rule L: Wetland Conservation Act Adoption Rule L: Shoreline Improvement Contractor's License Rule M: Shoreline Improvement Contractor's License TOTALS (2) PERCENTAGE OF TOTAL Chanhassen % Deephaven % Edina % Excelsior % Greenwood % Hopkins % Independence % town Township % Long % Medina % Minneapolis % Minnetonka % Minnetonka Beach % Minnetrista % Mound % Orono % Plymouth % Shorewood % Spring Park % St. Bonifacious % St. Louis Park % Tonka Bay % Victoria % Wayzata % Woodland % TOTALS (2) : PERCENTAGE 21.7% 7.0% 7.7% 1.4% 39.3% 2.6% 0.7% 0.5% 5.1% 0.7% 5.8% 7.5% 100.0% (1) A total of 279 permits were applied for in (2) Multiple rules apply to some permit applications Note: Rule K and Rule L definitions were altered during the year 1996.

4 Page 4 Total Phosphorus (mg/l) Wayzata Bay Average Annual Summer Surface Values Water quality trend graph showing phosphorus concentrations in Wayzata Bay on Minnetonka. Water quality monitoring plays a significant role in determining needed improvements as well as evaluating the performance of completed projects. Annual Hydrologic Monitoring (1968-Present) Since 1968, the District has been collecting hydrologic data throughout the watershed on an annual basis to define watershed hydrologic problems, provide information used in making watershed management decisions, and evaluate how well completed projects can function. The District has built one of the best long-term water quality and quantity data bases in the metropolitan area. The monitoring program has been modified and expanded throughout the years to more fully represent the quality and quantity aspects of the District s water resources. Since implementation in 1968, hydrologic data collected includes precipitation, lake levels, stream flows, lake and stream water quality, and groundwater levels and water quality. Monitoring results have been summarized in annual hydrologic data reports published by the District. Overall Plan for Water Management (1969) In 1969, the District s first water management plan was prepared. The plan identified surface and groundwater problems and possible corrective actions that could be taken alleviate the problems. The plan focused on three problem areas, namely water pollution, flood control, and low water levels during dry periods. Recommendations included removing all sewage treatment plant effluent from Minnetonka to improve water quality and reducing flooding along Minnehaha Creek by constructing an outlet control structure to regulate discharge from Minnetonka. Elimination of Municipal Wastewater Discharges to Minnetonka ( ) The District worked closely with local and regional governments to eliminate wastewater discharges to Minnetonka from seven municipal sewage treatment plants. Municipal wastewater discharges were phased out over a 15-year period from resulting a significant reduction in phosphorus loads to multiple streams, wetlands, and Minnetonka. A dramatic improvement in lake water quality was documented by the District's annual hydrologic monitoring.

5 Page 5 Summary of Past Municipal Wastewater Discharges to the Minnetonka Watershed Effluent Phosphorus Start Phase-Out Flow(1) Load(2) Municipality Receiving Water Date Date (mgd) (lb/yr) Excelsior Gideons Bay ,640 Long Tanager /Browns Bay ,160 Maple Plain Painter Creek/Jennings Bay ,130 Mound Langdon /Cooks Bay ,880 Orono French /Crystal Bay ,010 Victoria Auburn /Halsteds Bay ,160 Wayzata Peavey Pond/Browns Bay ,800 Notes: (1) Maple Plain flow in Victoria flow based on one-week field survey by MPCA in Other flows, average for two years prior to phase-out. (mgd = million gallons per day) (2) Effluent total phosphorus load in (lb/yr = pounds per year) Total 2 50,780 Wayzata Wetland Study for USEPA (1975) The District pioneered a federally funded wetland study in 1975 to evaluate how well wetlands treat urban stormwater runoff and remove nutrients such as phosphorus. A 7-acre wetland located in Wayzata with a 70-acre drainage area was selected for the study. The study defined the role natural wetlands play in the hydrologic cycle and demonstrated that wetlands are effective as a non-structural treatment method in removing nutrients and contaminants contained in urban stormwater runoff. The wetland used in the study retained 77 percent of all phosphorus and 94 percent of the total suspended solids entering the site during the evaluation period. Results from the District s wetland research were published by the U.S. EPA and became a national guidance document used in the management of urban stormwater runoff.

6 Page 6 Construction of an outlet control structure and improvements to Gray's Bay Dam helped to minimize flooding to communities downstream of Minnetonka. Construction of Gray s Bay Dam and Outlet ( ) One of the original goals of the District was to control flood damage along Minnehaha Creek. Most of the damage was occurring along the lower reach of the creek in commercial, residential, and park areas constructed within the floodplain. At the request of five communities located along the creek, the District improved the existing dam at Gray s Bay and constructed an outlet control structure in The purpose of the improvement was to manage water levels in Minnetonka and reduce downstream flooding along Minnehaha Creek. The outlet control structure was constructed with three adjustable stainless steel gates to release water at a controlled rate from about May to November and is equipped with a fish screen. The recreational facilities at the Gray s Bay Dam site were also upgraded by the District as part of this project including construction of a paved parking lot, picnic facilities, toilets, bike racks, drinking fountain, and canoe landing. Minnehaha Creek Channel Improvements at I-494 in Minnetonka ( ) A section of the upper reach of Minnehaha Creek was dredged by the District in the vicinity of the I-494/Minnetonka Blvd. interchange in to increase the flow capacity of the creek. This work, coordinated with the City of Minnetonka and Mn/DOT, involved lowering the creekbed by up to 2 feet by removing accumulated sediment along a 4,600-foot reach of the creek and stabilizing creekbanks. Minnehaha Creek channel dredging at I-494.

7 Page 7 Minnehaha Creek Recreational Improvements ( ) Recreational and channel improvements along Minnehaha Creek between its headwaters and France Avenue within the cities of Minnetonka, Hopkins, St. Louis Park, and Edina were completed by the District in This work included the construction of canoe landings and portages, parking areas, picnic and sanitary facilities, bike racks, wildlife ponds, raising of pedestrian bridges, installation of culverts, and minor channel maintenance and repair. Minnehaha Creek Channel Improvements at West 44th Street in Edina (1981) In 1981, the District dredged out a 1,300-foot section of Minnehaha Creek in the vicinity of West 44th Street in Edina. The project, funded jointly with the City of Edina, improved the flow capacity of the channel resulting in lower upstream flood elevations. In 1980, the District completed recreational and channel improvements that included the installation of canoe landings along portions of Minnehaha Creek (Utley Park canoe landing shown above). Hydraulic/Flood Study of Minnehaha Creek in Minneapolis ( ) In the District and City of Minneapolis jointly undertook a hydraulic study of flooding along a portion of Minnehaha Creek west of I-35W. The study made use of a HEC-2 stream hydraulic model application previously developed by the U.S. Geological Survey for a flood insurance investigation. Flood impacts were evaluated for six existing bridges and culverts. Impacts were found to be large at three of these locations. Beneficial hydraulic effects were investigated for three possible designs proposed by the City for the Logan Avenue bridge, a larger culvert at Penn Avenue, and removal of an abandoned bridge. Reductions of up to 2 feet in 50-year flood stage were found to result from these modifications and several homes were afforded more flood protection. The study recommended a new single-span Logan Avenue bridge and a wider, higher Penn Avenue culvert. Removal of the abandoned bridge near Pleasant Avenue was not justifiable on the basis of flood impacts alone because the location is far downstream from flood-sensitive residential areas. TR-20 Runoff Model (1983) Surface water runoff impacts many District activities including floodplain management, stream flow forecasting, lake level regulation, drainage system design, water quality control, recreation, and fish and wildlife management. The District has modeled the entire watershed using the Soil Conservation Service TR-20 computer model under the existing and unmanaged future conditions for the 1, 10, and 100-year storm events. These values assist in establishing a framework for effective water quantity management. The model was first developed for the watershed in 1983 and later updated in The extensive effort involved the modeling of 153 individual subwatersheds. Modeling results are included in the District s water resources management plan.

8 Page 8 Minnehaha Creek Channel Improvements at T.H. 100 in Edina (1984) Under a cooperative project with the City of Edina and Mn/DOT, the District reconstructed a 300-foot section of Minnehaha Creek upstream and downstream of the Highway 100 bridge crossing to restore the creek channel profile to that of the original bridge design plans from The project was planned and funded jointly with the City and Mn/DOT, and designed and built by the District. The channel improvements resulted in the lowering of the surface water profile upstream of Highway 100 where low-lying properties are located within the 100-year floodplain. Painter Marsh. Painter Creek Subwatershed Improvement Project ( ) Painter Creek, a major tributary to Minnetonka, was known to carry large amounts of sediment and phosphorus from its 8,500 acre drainage area. During the winter of , the District constructed four detention basins, two sedimentation basins, and one fish barrier within the Painter Creek Subwatershed. A one mile stretch of Painter Creek was also cleaned and repaired. The project reduced nonpoint source pollution from the Painter Creek subwatershed improving water quality in Minnetonka and also provided an additional 900 acre-feet of flood storage under 100-year storm conditions. Draft Water Resources Management Plan (1987) In 1982, Minnesota Legislature adopted the Metropolitan Surface Water Management Act (Chapter 509) mandating that all watersheds within the Twin Cities Metropolitan Area be governed by a watershed management organization and that watershed management plans be prepared. In accordance with the law, the District completed a draft water resources management plan in 1987 focusing on preservation and use of natural water storage and retention systems and designed to achieve the following five basic primary objectives: To reduce, to the greatest possible extent, the public expenditures necessary to control excessive volumes and rates of runoff. To improve water quality. To prevent flooding and erosion from surface flows. To promote groundwater recharge. To protect and enhance fish and wildlife habitat and water recreation facilities. The plan was submitted to various agencies for review and comment and to the Board of Soil and Water Resources for approval.

9 Page 9 Long Diagnostic/Feasibility Study ( ) In 1989, the District undertook a study of Long to assess its water quality (diagnostic study) and to develop a plan for water quality improvement (feasibility study). Field work included lake, stream, and storm sewer monitoring, and was conducted during the period October September 1990 (water year 1990). Long was found to be in an advanced stage of eutrophication. For the 1990 summer season, Secchi transparency averaged only 3 feet, chlorophyll-a levels indicated frequent nuisance algae blooms, and total phosphorus concentrations averaged two to four times higher than is typical for unimpacted lakes in the ecoregion. The quantity of phosphorus released into the water from bottom sediments (internal load) was found to be comparable to the inputs from streams and other sources (external load); each of these loads was a little over 3,000 pounds per year. To reduce the external load, a wet detention pond was recommended along the lake s main tributary near County Road 6, along with upgrading of stormwater ponds in a park in the City of Long. The recommendation for reducing internal load was originally enhanced aeration, but a change was later made to alum treatment. The diagnostic/feasibility study report was published in 1993, with a further report on feasibility completed in Approval of Water Resources Management Plan (1993) After a lengthy review process, the District s water resources management plan was approved in 1993 by the Board of Water and Soil Resources which paved the way for several District water quality improvement projects. Gleason Creek Improvement and Flood Control Project ( ) In 1994, the District completed the construction of Phase One of the Gleason Creek Improvement Project, a cooperative project with the City of Wayzata. The project involved construction of a new outlet control structure on Gleason, expansion of one and creation of a second stormwater pond and extensive storm sewer improvements. The project provides significantly improved flood control along Gleason Creek and improved water quality in Minnetonka. In 1995, the District completed Phase Two of the Project which focused on improving the water quality of Gleason by reconstruction and enhancement of a wetland at the inlet to the lake. Construction of this outlet structure on Gleason provided improved flood control along Gleason Creek.

10 Page 10 Twin s dredging. The Cedar Meadows wet detention basin/ wetland system treats inflows to nearby Cedar. Twin s Subwatershed Improvement Project ( ) In a cooperative effort to restore water quality in the Minneapolis Chain of s, the District entered into a partnership (Clean Water Partnership) with the cities of Minneapolis and St. Louis Park, the Minneapolis Park and Recreation Board, and Hennepin County. A feasibility study was performed by the District in 1994 to provide technical recommendations for watershed improvements to the Twin s Subwatershed, a 1,500 acre drainage area consisting of welldeveloped residential and commercial areas in St. Louis Park that contribute over 50% of the flow and over 60% of the phosphorus load to Cedar. The goal of the project was to optimize water quality improvement of stormwater runoff entering Twin s and Cedar by removing phosphorus, sediment, and other pollutants naturally through physical and biological processes. Designed, built, and funded by the District, the initial phase of structural water quality improvements were completed in These improvements consisted of constructing a wet detention basin upstream of Twin s and a wet detention basin/wetland system near Cedar, dredging Twin s, and diverting stormwater runoff. Long Improvement Project ( ) The first phase of watershed improvements, completed in 1996 as part of the Long Improvement Project, involved the construction of a large two-cell wet detention basin in Medina, on a major tributary to Long, and the expansion and enhancement of two existing sedimentation basins in the City of Long. A subsequent project phase including the construction of an additional wet detention basin in Orono is planned to be completed in View prior to construction of the wet detention basin in Medina. After construction of the wet detention basin.

11 Page 11 Long Alum Treatment (1996) Long was treated with aluminum sulfate (alum) by the District in the Spring of 1996 to remove phosphorus from the water column and to retard the release of phosphorus from lake bottom sediments. By late summer of that year, water clarity in Long had increased from 2 feet to 15 feet. Alum has proven to provide a safe and effective solution to control of the amount of algae present in lakes. Long alum application. MDNR Outstanding Watershed District of the Year (1996) The MCWD was honored as watershed district of the year at the 1996 Minnesota Association of Watershed Districts (MAWD) annual meeting. The Outstanding Watershed District Award was presented to the District by the Minnesota Department of Natural Resources (DNR). In presenting the award, the DNR cited four to the District s major achievements: Working with the DNR on a streamlined process for obtaining general permits. Enhancing MCWD rules to provide for better adherence to the land alteration requirements. Adopting a wetland buffer requirement to further protect wetland resources. Developing Minnesota s first watershed Internet site and helping develop on Internet presence for the remaining 41 state watershed districts on the MAWD Home Page. Thirty years of proactive management of the Minnehaha Creek Watershed has provided the community with an exceptional recreational and aesthetic environment. The District was also recognized for using regulation, education, and water resource projects in a comprehensive way to protect and improve the water resources in the most heavily populated district in the state. Painter Creek Subwatershed Maintenance Project ( ) Designed to restore the flood storage capacity created by the 1985 project and enhance the water quality treatment capability, accumulated sediment was removed and the two existing basins enlarged and depend at the South Katrina and Painter Marsh sites by the District in The existing outlets were also modified to prevent blockages.

12 Page 12 Wetland Watershed Boundary (Approximately 50 Acres) 5 WETLAND BASIN 41 Minnesota Landscape Arboretum Wetland Restoration ( ) The Spring Peeper Meadow Restoration project at the University of Minnesota Landscape Arboretum in Chanhassen was completed in The District provided $250,000 toward this wetland restoration project which will be showcased for public learning, experiences, demonstrations, and on-going research on wetland regeneration. The site s hydrology was restored by breaking the network of drain tiles below the soil surface. Native plant species were planted in the wetland basin and a boardwalk and interpretive trail constructed within the basin to provide access to the 20-acre wetland for close viewing and plant identification. N 82nd STREET Contributing to the Minnesota Landscape Arboretum is one method the District uses to help promote watershed education. Gray s Bay Outlet Maintenance and Repair (1997) The overflow spillway at the Gray s Bay outlet had fallen into disrepair over the years through erosion and settlement. Maintenance and repair of the structure was performed by the District in 1997 to ensure proper and safe implementation of the existing operation plan. This work consisted of installing timber piles to stabilize the steel sheet pile weir and constructing a new weir cap; placing riprap, boulders, and cobbles along the lake side of the weir; filling and grading earth material for erosion protection and to confine lake overflow to the weir area; extending and adding fences for safety; and removing large downed cottonwood trees. Maintenance and repairs to the Gray's Bay overflow spillway were conducted in early View of overflow spillway after completion of repairs.

13 Page 13 Approval of 2nd Generation Water Resources Management Plan (1997) The District s 2nd Generation Water Resources Management Plan was approved by the Board of Water and Soil Resources in The plan identifies a series of capital improvement projects throughout the District, as well as specific strategies to reduce the continuing degradation of surface water in the watershed. The plan also reflects the District s goals and policies for water resources management and protection, including the District s increased emphasis on education and public participation. Minnehaha Creek. Please visit our Web Site at

14 Page 2 The year 1997 marks the 30th year of the Minnehaha Creek Watershed District (MCWD). The MCWD is one of the largest watershed districts in the Twin Cities metropolitan area. The District covers an area of 181 square miles in Hennepin and Carver Counties. The watershed extends 29 miles from St. Bonifacius in western Hennepin County to the Mississippi River in Minneapolis and includes all or portions of 30 communities. There are 109 lakes, eight major creeks, and thousands of wetlands. Important water resources located within the district include Minnetonka, Minnehaha Creek, the Minneapolis Chain of s, and Minnehaha Falls. The District is managed by a seven-member Board of Managers appointed by Hennepin County (6) and Carver County (1). The District has been a leader in planning and implementing water management projects and policies to improve water quality and reduce flooding. Major studies, projects, activities, and accomplishments over the past 30-years are highlighted in this booklet. Establishment of the MCWD (1967) The was established in 1967 under the authority of the state legislature at the request of the Hennepin County Board of Commissioners. The petition filed by the County in 1966 sought establishment of the district to conserve the waters and natural resources of the watershed. Their goals included improving lakes, marshes and channels for water storage, drainage, recreation and other public purposes. The County also wanted to develop projects to reduce flooding, to keep silt out of streams, and to control erosion of land. Other goals were reclaiming wetlands, controlling stormwater, and preserving water quality within the District s lakes and streams. Minnehaha Creek Watershed District Holy Name INDEPENDENCE 110 MAPLE PLAIN Katrina 12 LONG LAKE Wolsfied Long Mooney PLYMOUTH 101 Dutch Langdon 110 WATERTOWN ST. BONIFACIUS MINNETRISTA Mud SPRING PARK MOUND MCWD OFFICE Upper Minnetonka Gleason WAYZATA ORONO 15 Gray's Bay Dam WOODLAND Lower Minnetonka DEEPHAVEN TONKA BAY GREENWOOD 7 EXCELSIOR Christmas Virginia MINNETONKA GOLDEN VALLEY Brownie of the Isles Twin s 169 ST. LOUIS Cedar PARK Bass 7 Calhoun 100 HOPKINS Harriet Minnehaha Creek EDINA W MINNEAPOLIS Hiawatha Nokomis Minnehaha Falls Mississippi River Stone Parley Zumbra VICTORIA Shultz Minnewashta Lunsten Auburn Steiger CHANHASSEN 5 LAKETOWN Wasserman Pierson CARVER CO. HENNEPIN CO W RICHFIELD Marsh

15 Page Permit Applications Regulatory Program (1967-Present) A regulatory program was initiated in 1967 to mitigate the impacts of new land development and other projects on water resources within the District. Through the regulatory program, the District has reviewed and approved stormwater management plans and shaped projects in floodplains and wetlands. The regulatory program has also covered dredging, stream and lake crossings, and shoreline improvement projects. To date, the District has issued over 2,000 permits. Rule B: Stormwater Management Plans Rule C: Floodplain Alteration Rule D: Wetland Protection Rule E: Dredging Rule F: Shoreline and Streambank Improvements Rule G: Stream & Crossings Rule I: Variances Rule K: Dredging Contractor License Rule K: Performance Bond or Letter of Credit Rule L: Wetland Conservation Act Adoption Rule L: Shoreline Improvement Contractor's License Rule M: Shoreline Improvement Contractor's License TOTALS (2) PERCENTAGE OF TOTAL Chanhassen % Deephaven % Edina % Excelsior % Greenwood % Hopkins % Independence % town Township % Long % Medina % Minneapolis % Minnetonka % Minnetonka Beach % Minnetrista % Mound % Orono % Plymouth % Shorewood % Spring Park % St. Bonifacious % St. Louis Park % Tonka Bay % Victoria % Wayzata % Woodland % TOTALS (2) : PERCENTAGE 21.7% 7.0% 7.7% 1.4% 39.3% 2.6% 0.7% 0.5% 5.1% 0.7% 5.8% 7.5% 100.0% (1) A total of 279 permits were applied for in (2) Multiple rules apply to some permit applications Note: Rule K and Rule L definitions were altered during the year 1996.

16 Page 4 Total Phosphorus (mg/l) Wayzata Bay Average Annual Summer Surface Values Water quality trend graph showing phosphorus concentrations in Wayzata Bay on Minnetonka. Water quality monitoring plays a significant role in determining needed improvements as well as evaluating the performance of completed projects. Annual Hydrologic Monitoring (1968-Present) Since 1968, the District has been collecting hydrologic data throughout the watershed on an annual basis to define watershed hydrologic problems, provide information used in making watershed management decisions, and evaluate how well completed projects can function. The District has built one of the best long-term water quality and quantity data bases in the metropolitan area. The monitoring program has been modified and expanded throughout the years to more fully represent the quality and quantity aspects of the District s water resources. Since implementation in 1968, hydrologic data collected includes precipitation, lake levels, stream flows, lake and stream water quality, and groundwater levels and water quality. Monitoring results have been summarized in annual hydrologic data reports published by the District. Overall Plan for Water Management (1969) In 1969, the District s first water management plan was prepared. The plan identified surface and groundwater problems and possible corrective actions that could be taken alleviate the problems. The plan focused on three problem areas, namely water pollution, flood control, and low water levels during dry periods. Recommendations included removing all sewage treatment plant effluent from Minnetonka to improve water quality and reducing flooding along Minnehaha Creek by constructing an outlet control structure to regulate discharge from Minnetonka. Elimination of Municipal Wastewater Discharges to Minnetonka ( ) The District worked closely with local and regional governments to eliminate wastewater discharges to Minnetonka from seven municipal sewage treatment plants. Municipal wastewater discharges were phased out over a 15-year period from resulting a significant reduction in phosphorus loads to multiple streams, wetlands, and Minnetonka. A dramatic improvement in lake water quality was documented by the District's annual hydrologic monitoring.

17 Page 5 Summary of Past Municipal Wastewater Discharges to the Minnetonka Watershed Effluent Phosphorus Start Phase-Out Flow(1) Load(2) Municipality Receiving Water Date Date (mgd) (lb/yr) Excelsior Gideons Bay ,640 Long Tanager /Browns Bay ,160 Maple Plain Painter Creek/Jennings Bay ,130 Mound Langdon /Cooks Bay ,880 Orono French /Crystal Bay ,010 Victoria Auburn /Halsteds Bay ,160 Wayzata Peavey Pond/Browns Bay ,800 Notes: (1) Maple Plain flow in Victoria flow based on one-week field survey by MPCA in Other flows, average for two years prior to phase-out. (mgd = million gallons per day) (2) Effluent total phosphorus load in (lb/yr = pounds per year) Total 2 50,780 Wayzata Wetland Study for USEPA (1975) The District pioneered a federally funded wetland study in 1975 to evaluate how well wetlands treat urban stormwater runoff and remove nutrients such as phosphorus. A 7-acre wetland located in Wayzata with a 70-acre drainage area was selected for the study. The study defined the role natural wetlands play in the hydrologic cycle and demonstrated that wetlands are effective as a non-structural treatment method in removing nutrients and contaminants contained in urban stormwater runoff. The wetland used in the study retained 77 percent of all phosphorus and 94 percent of the total suspended solids entering the site during the evaluation period. Results from the District s wetland research were published by the U.S. EPA and became a national guidance document used in the management of urban stormwater runoff.

18 Page 6 Construction of an outlet control structure and improvements to Gray's Bay Dam helped to minimize flooding to communities downstream of Minnetonka. Construction of Gray s Bay Dam and Outlet ( ) One of the original goals of the District was to control flood damage along Minnehaha Creek. Most of the damage was occurring along the lower reach of the creek in commercial, residential, and park areas constructed within the floodplain. At the request of five communities located along the creek, the District improved the existing dam at Gray s Bay and constructed an outlet control structure in The purpose of the improvement was to manage water levels in Minnetonka and reduce downstream flooding along Minnehaha Creek. The outlet control structure was constructed with three adjustable stainless steel gates to release water at a controlled rate from about May to November and is equipped with a fish screen. The recreational facilities at the Gray s Bay Dam site were also upgraded by the District as part of this project including construction of a paved parking lot, picnic facilities, toilets, bike racks, drinking fountain, and canoe landing. Minnehaha Creek Channel Improvements at I-494 in Minnetonka ( ) A section of the upper reach of Minnehaha Creek was dredged by the District in the vicinity of the I-494/Minnetonka Blvd. interchange in to increase the flow capacity of the creek. This work, coordinated with the City of Minnetonka and Mn/DOT, involved lowering the creekbed by up to 2 feet by removing accumulated sediment along a 4,600-foot reach of the creek and stabilizing creekbanks. Minnehaha Creek channel dredging at I-494.

19 Page 7 Minnehaha Creek Recreational Improvements ( ) Recreational and channel improvements along Minnehaha Creek between its headwaters and France Avenue within the cities of Minnetonka, Hopkins, St. Louis Park, and Edina were completed by the District in This work included the construction of canoe landings and portages, parking areas, picnic and sanitary facilities, bike racks, wildlife ponds, raising of pedestrian bridges, installation of culverts, and minor channel maintenance and repair. Minnehaha Creek Channel Improvements at West 44th Street in Edina (1981) In 1981, the District dredged out a 1,300-foot section of Minnehaha Creek in the vicinity of West 44th Street in Edina. The project, funded jointly with the City of Edina, improved the flow capacity of the channel resulting in lower upstream flood elevations. In 1980, the District completed recreational and channel improvements that included the installation of canoe landings along portions of Minnehaha Creek (Utley Park canoe landing shown above). Hydraulic/Flood Study of Minnehaha Creek in Minneapolis ( ) In the District and City of Minneapolis jointly undertook a hydraulic study of flooding along a portion of Minnehaha Creek west of I-35W. The study made use of a HEC-2 stream hydraulic model application previously developed by the U.S. Geological Survey for a flood insurance investigation. Flood impacts were evaluated for six existing bridges and culverts. Impacts were found to be large at three of these locations. Beneficial hydraulic effects were investigated for three possible designs proposed by the City for the Logan Avenue bridge, a larger culvert at Penn Avenue, and removal of an abandoned bridge. Reductions of up to 2 feet in 50-year flood stage were found to result from these modifications and several homes were afforded more flood protection. The study recommended a new single-span Logan Avenue bridge and a wider, higher Penn Avenue culvert. Removal of the abandoned bridge near Pleasant Avenue was not justifiable on the basis of flood impacts alone because the location is far downstream from flood-sensitive residential areas. TR-20 Runoff Model (1983) Surface water runoff impacts many District activities including floodplain management, stream flow forecasting, lake level regulation, drainage system design, water quality control, recreation, and fish and wildlife management. The District has modeled the entire watershed using the Soil Conservation Service TR-20 computer model under the existing and unmanaged future conditions for the 1, 10, and 100-year storm events. These values assist in establishing a framework for effective water quantity management. The model was first developed for the watershed in 1983 and later updated in The extensive effort involved the modeling of 153 individual subwatersheds. Modeling results are included in the District s water resources management plan.

20 Page 8 Minnehaha Creek Channel Improvements at T.H. 100 in Edina (1984) Under a cooperative project with the City of Edina and Mn/DOT, the District reconstructed a 300-foot section of Minnehaha Creek upstream and downstream of the Highway 100 bridge crossing to restore the creek channel profile to that of the original bridge design plans from The project was planned and funded jointly with the City and Mn/DOT, and designed and built by the District. The channel improvements resulted in the lowering of the surface water profile upstream of Highway 100 where low-lying properties are located within the 100-year floodplain. Painter Marsh. Painter Creek Subwatershed Improvement Project ( ) Painter Creek, a major tributary to Minnetonka, was known to carry large amounts of sediment and phosphorus from its 8,500 acre drainage area. During the winter of , the District constructed four detention basins, two sedimentation basins, and one fish barrier within the Painter Creek Subwatershed. A one mile stretch of Painter Creek was also cleaned and repaired. The project reduced nonpoint source pollution from the Painter Creek subwatershed improving water quality in Minnetonka and also provided an additional 900 acre-feet of flood storage under 100-year storm conditions. Draft Water Resources Management Plan (1987) In 1982, Minnesota Legislature adopted the Metropolitan Surface Water Management Act (Chapter 509) mandating that all watersheds within the Twin Cities Metropolitan Area be governed by a watershed management organization and that watershed management plans be prepared. In accordance with the law, the District completed a draft water resources management plan in 1987 focusing on preservation and use of natural water storage and retention systems and designed to achieve the following five basic primary objectives: To reduce, to the greatest possible extent, the public expenditures necessary to control excessive volumes and rates of runoff. To improve water quality. To prevent flooding and erosion from surface flows. To promote groundwater recharge. To protect and enhance fish and wildlife habitat and water recreation facilities. The plan was submitted to various agencies for review and comment and to the Board of Soil and Water Resources for approval.

21 Page 9 Long Diagnostic/Feasibility Study ( ) In 1989, the District undertook a study of Long to assess its water quality (diagnostic study) and to develop a plan for water quality improvement (feasibility study). Field work included lake, stream, and storm sewer monitoring, and was conducted during the period October September 1990 (water year 1990). Long was found to be in an advanced stage of eutrophication. For the 1990 summer season, Secchi transparency averaged only 3 feet, chlorophyll-a levels indicated frequent nuisance algae blooms, and total phosphorus concentrations averaged two to four times higher than is typical for unimpacted lakes in the ecoregion. The quantity of phosphorus released into the water from bottom sediments (internal load) was found to be comparable to the inputs from streams and other sources (external load); each of these loads was a little over 3,000 pounds per year. To reduce the external load, a wet detention pond was recommended along the lake s main tributary near County Road 6, along with upgrading of stormwater ponds in a park in the City of Long. The recommendation for reducing internal load was originally enhanced aeration, but a change was later made to alum treatment. The diagnostic/feasibility study report was published in 1993, with a further report on feasibility completed in Approval of Water Resources Management Plan (1993) After a lengthy review process, the District s water resources management plan was approved in 1993 by the Board of Water and Soil Resources which paved the way for several District water quality improvement projects. Gleason Creek Improvement and Flood Control Project ( ) In 1994, the District completed the construction of Phase One of the Gleason Creek Improvement Project, a cooperative project with the City of Wayzata. The project involved construction of a new outlet control structure on Gleason, expansion of one and creation of a second stormwater pond and extensive storm sewer improvements. The project provides significantly improved flood control along Gleason Creek and improved water quality in Minnetonka. In 1995, the District completed Phase Two of the Project which focused on improving the water quality of Gleason by reconstruction and enhancement of a wetland at the inlet to the lake. Construction of this outlet structure on Gleason provided improved flood control along Gleason Creek.

22 Page 10 Twin s dredging. The Cedar Meadows wet detention basin/ wetland system treats inflows to nearby Cedar. Twin s Subwatershed Improvement Project ( ) In a cooperative effort to restore water quality in the Minneapolis Chain of s, the District entered into a partnership (Clean Water Partnership) with the cities of Minneapolis and St. Louis Park, the Minneapolis Park and Recreation Board, and Hennepin County. A feasibility study was performed by the District in 1994 to provide technical recommendations for watershed improvements to the Twin s Subwatershed, a 1,500 acre drainage area consisting of welldeveloped residential and commercial areas in St. Louis Park that contribute over 50% of the flow and over 60% of the phosphorus load to Cedar. The goal of the project was to optimize water quality improvement of stormwater runoff entering Twin s and Cedar by removing phosphorus, sediment, and other pollutants naturally through physical and biological processes. Designed, built, and funded by the District, the initial phase of structural water quality improvements were completed in These improvements consisted of constructing a wet detention basin upstream of Twin s and a wet detention basin/wetland system near Cedar, dredging Twin s, and diverting stormwater runoff. Long Improvement Project ( ) The first phase of watershed improvements, completed in 1996 as part of the Long Improvement Project, involved the construction of a large two-cell wet detention basin in Medina, on a major tributary to Long, and the expansion and enhancement of two existing sedimentation basins in the City of Long. A subsequent project phase including the construction of an additional wet detention basin in Orono is planned to be completed in View prior to construction of the wet detention basin in Medina. After construction of the wet detention basin.

23 Page 11 Long Alum Treatment (1996) Long was treated with aluminum sulfate (alum) by the District in the Spring of 1996 to remove phosphorus from the water column and to retard the release of phosphorus from lake bottom sediments. By late summer of that year, water clarity in Long had increased from 2 feet to 15 feet. Alum has proven to provide a safe and effective solution to control of the amount of algae present in lakes. Long alum application. MDNR Outstanding Watershed District of the Year (1996) The MCWD was honored as watershed district of the year at the 1996 Minnesota Association of Watershed Districts (MAWD) annual meeting. The Outstanding Watershed District Award was presented to the District by the Minnesota Department of Natural Resources (DNR). In presenting the award, the DNR cited four to the District s major achievements: Working with the DNR on a streamlined process for obtaining general permits. Enhancing MCWD rules to provide for better adherence to the land alteration requirements. Adopting a wetland buffer requirement to further protect wetland resources. Developing Minnesota s first watershed Internet site and helping develop on Internet presence for the remaining 41 state watershed districts on the MAWD Home Page. Thirty years of proactive management of the Minnehaha Creek Watershed has provided the community with an exceptional recreational and aesthetic environment. The District was also recognized for using regulation, education, and water resource projects in a comprehensive way to protect and improve the water resources in the most heavily populated district in the state. Painter Creek Subwatershed Maintenance Project ( ) Designed to restore the flood storage capacity created by the 1985 project and enhance the water quality treatment capability, accumulated sediment was removed and the two existing basins enlarged and depend at the South Katrina and Painter Marsh sites by the District in The existing outlets were also modified to prevent blockages.

24 Page 12 Wetland Watershed Boundary (Approximately 50 Acres) 5 WETLAND BASIN 41 Minnesota Landscape Arboretum Wetland Restoration ( ) The Spring Peeper Meadow Restoration project at the University of Minnesota Landscape Arboretum in Chanhassen was completed in The District provided $250,000 toward this wetland restoration project which will be showcased for public learning, experiences, demonstrations, and on-going research on wetland regeneration. The site s hydrology was restored by breaking the network of drain tiles below the soil surface. Native plant species were planted in the wetland basin and a boardwalk and interpretive trail constructed within the basin to provide access to the 20-acre wetland for close viewing and plant identification. N 82nd STREET Contributing to the Minnesota Landscape Arboretum is one method the District uses to help promote watershed education. Gray s Bay Outlet Maintenance and Repair (1997) The overflow spillway at the Gray s Bay outlet had fallen into disrepair over the years through erosion and settlement. Maintenance and repair of the structure was performed by the District in 1997 to ensure proper and safe implementation of the existing operation plan. This work consisted of installing timber piles to stabilize the steel sheet pile weir and constructing a new weir cap; placing riprap, boulders, and cobbles along the lake side of the weir; filling and grading earth material for erosion protection and to confine lake overflow to the weir area; extending and adding fences for safety; and removing large downed cottonwood trees. Maintenance and repairs to the Gray's Bay overflow spillway were conducted in early View of overflow spillway after completion of repairs.

25 Page 13 Approval of 2nd Generation Water Resources Management Plan (1997) The District s 2nd Generation Water Resources Management Plan was approved by the Board of Water and Soil Resources in The plan identifies a series of capital improvement projects throughout the District, as well as specific strategies to reduce the continuing degradation of surface water in the watershed. The plan also reflects the District s goals and policies for water resources management and protection, including the District s increased emphasis on education and public participation. Minnehaha Creek. Please visit our Web Site at

26 Page 2 The year 1997 marks the 30th year of the Minnehaha Creek Watershed District (MCWD). The MCWD is one of the largest watershed districts in the Twin Cities metropolitan area. The District covers an area of 181 square miles in Hennepin and Carver Counties. The watershed extends 29 miles from St. Bonifacius in western Hennepin County to the Mississippi River in Minneapolis and includes all or portions of 30 communities. There are 109 lakes, eight major creeks, and thousands of wetlands. Important water resources located within the district include Minnetonka, Minnehaha Creek, the Minneapolis Chain of s, and Minnehaha Falls. The District is managed by a seven-member Board of Managers appointed by Hennepin County (6) and Carver County (1). The District has been a leader in planning and implementing water management projects and policies to improve water quality and reduce flooding. Major studies, projects, activities, and accomplishments over the past 30-years are highlighted in this booklet. Establishment of the MCWD (1967) The was established in 1967 under the authority of the state legislature at the request of the Hennepin County Board of Commissioners. The petition filed by the County in 1966 sought establishment of the district to conserve the waters and natural resources of the watershed. Their goals included improving lakes, marshes and channels for water storage, drainage, recreation and other public purposes. The County also wanted to develop projects to reduce flooding, to keep silt out of streams, and to control erosion of land. Other goals were reclaiming wetlands, controlling stormwater, and preserving water quality within the District s lakes and streams. Minnehaha Creek Watershed District Holy Name INDEPENDENCE 110 MAPLE PLAIN Katrina 12 LONG LAKE Wolsfied Long Mooney PLYMOUTH 101 Dutch Langdon 110 WATERTOWN ST. BONIFACIUS MINNETRISTA Mud SPRING PARK MOUND MCWD OFFICE Upper Minnetonka Gleason WAYZATA ORONO 15 Gray's Bay Dam WOODLAND Lower Minnetonka DEEPHAVEN TONKA BAY GREENWOOD 7 EXCELSIOR Christmas Virginia MINNETONKA GOLDEN VALLEY Brownie of the Isles Twin s 169 ST. LOUIS Cedar PARK Bass 7 Calhoun 100 HOPKINS Harriet Minnehaha Creek EDINA W MINNEAPOLIS Hiawatha Nokomis Minnehaha Falls Mississippi River Stone Parley Zumbra VICTORIA Shultz Minnewashta Lunsten Auburn Steiger CHANHASSEN 5 LAKETOWN Wasserman Pierson CARVER CO. HENNEPIN CO W RICHFIELD Marsh