Minnehaha Creek Watershed District Comprehensive Water Resources Management Plan 2007-2017 Wenck File #0185-4315 Prepared for: MINNEHAHA CREEK WATERSHED DISTRICT Prepared by: February 2007 WENCK ASSOCIATES, INC. 1800 Pioneer Creek Center P.O. Box 249 Maple Plain, Minnesota 55359-0249 (763) 479-4200 Table of Contents 1.0 Introduction........................................................................................................................................1 1.1 Introduction and Purpose....................................................................................................1 1.2 Metropolitan Surface Water Management Act ...................................................................1 1.3 Membership of Board of Managers ....................................................................................2 1.4 General Boundaries.............................................................................................................2 1.4.1 Governmental Units Within District Boundaries ................................................3 1.5 History of the Minnehaha Creek Watershed District ..........................................................4 1.6 Context of Plan....................................................................................................................5 1.7 Summary of Problems, Goals, and Solutions......................................................................6 1.7.1 General Problems and Goals ...............................................................................6 1.7.2 General Solutions................................................................................................8 1.8 General Content Required of Local Plans.........................................................................11 1.9 Plan Organization..............................................................................................................11 2.0 Land and Natural Resources Inventory............................................................................................13 2.1 Introduction.......................................................................................................................13 2.2 Physical Environment .......................................................................................................13 2.2.1 Climate ..............................................................................................................13 2.2.2 Topography and Drainage .................................................................................15 2.2.3 Geology .............................................................................................................17 2.2.4 Soils...................................................................................................................17 2.2.5 Unique Features and Scenic Areas ....................................................................19 2.3 Biological Environment ....................................................................................................19 2.3.1 Vegetation..........................................................................................................19 2.3.2 Fish and Wildlife ...............................................................................................20 2.4 Human Environment .........................................................................................................24 2.4.1 History ...............................................................................................................24 2.4.2 Demography ......................................................................................................25 2.4.3 Present Land Use & Land Cover.......................................................................26 2.4.4 2020 and 2030 Land Use Planning....................................................................26 2.4.5 Metropolitan Systems........................................................................................27 2.4.6 Open Space and Recreation...............................................................................27 2.4.7 Potential Environmental Hazards ......................................................................28 3.0 Hydrologic Systems .........................................................................................................................30 3.1 Introduction.......................................................................................................................30 3.1.1 Precipitation.......................................................................................................30 3.1.2 Design Storms...................................................................................................30 3.2 Water Resources................................................................................................................30 3.2.1 Public Waters.....................................................................................................30 3.2.2 Lakes .................................................................................................................31 3.2.3 Streams ..............................................................................................................33 3.2.4 Ditches...............................................................................................................34 3.2.5 Wetlands............................................................................................................35 3.2.6 Floodplain..........................................................................................................37 3.3 Water Quantity..................................................................................................................38 3.4 Water Quality....................................................................................................................39 3.4.1 Water Quality....................................................................................................39 Minnehaha Creek Watershed District i February 2007 Comprehensive Water Resources Management Plan 3.4.2 Impacts from Historical Municipal Wastewater Treatment Plant Discharges ..39 3.4.3 Impaired Waters................................................................................................41 3.5 Groundwater......................................................................................................................42 3.5.1 Aquifers .............................................................................................................42 3.5.2 Groundwater Quality.........................................................................................42 3.5.3 Surface-Groundwater Interface .........................................................................43 3.5.4 Infiltration Capacity...........................................................................................43 3.5.5 Wellhead Protection..........................................................................................44 4.0 Issues Identification .........................................................................................................................45 4.1 Integration of Past Planning Efforts..................................................................................45 4.1.1 Hydrologic/Hydraulic and Pollutant Loading Study .........................................45 4.1.2 Functional Assessment of Wetlands..................................................................46 4.1.3 Stream Assessments ..........................................................................................46 4.1.4 Creek Visioning.................................................................................................46 4.1.5 Hydrologic Data Program..................................................................................47 4.2 Basic Plan Assumptions....................................................................................................48 4.2.1 What is Water Quality? .....................................................................................48 4.2.2 Integrated Resource Management .....................................................................49 4.2.3 Ultimate Land Use.............................................................................................49 4.3 Regulatory Issues ..............................................................................................................50 4.3.1 Rules and Standards ..........................................................................................50 4.3.2 TMDLs/NPDES/Nondegradation......................................................................50 4.4 Water Quality Issues .........................................................................................................51 4.5 Water Quantity Issues .......................................................................................................51 4.6 Ditch Issues .......................................................................................................................52 4.7 Wetland Issues ..................................................................................................................52 4.8 Ecological Integrity Issues ................................................................................................53 4.9 Groundwater......................................................................................................................53 4.10 General Solutions..............................................................................................................53