Surface Water Management Plan 2018–2027 Prepared for the City of Apple Valley October 2018 Surface Water Management Plan 2018-2027 Prepared for the City of Apple Valley October 2018 Barr Engineering Co. Surface Water Management Plan October 2018 Contents Executive Summary ....................................................................................................................................................................... ES-1 1.0 Introduction ....................................................................................................................................................................... 1-1 1.1 Location and History ................................................................................................................................................. 1-1 1.2 Purpose and Scope .................................................................................................................................................... 1-1 1.3 Water Resource Agreements ................................................................................................................................. 1-2 1.4 SWMP Update, Amendment, and Reporting ................................................................................................... 1-3 2.0 Land and Water Resource Inventory ........................................................................................................................ 2-1 2.1 Climate and Precipitation ........................................................................................................................................ 2-1 2.1.1 Storm Event Precipitation .................................................................................................................................. 2-1 2.1.2 Precipitation Variability and Trends ............................................................................................................... 2-2 2.2 Topography and Drainage ...................................................................................................................................... 2-3 2.2.1 Drainage Divides .................................................................................................................................................... 2-3 2.3 Soils .................................................................................................................................................................................. 2-4 2.4 Geology and Groundwater ..................................................................................................................................... 2-5 2.4.1 Bedrock Aquifers ................................................................................................................................................... 2-5 2.4.2 Surficial Aquifers .................................................................................................................................................... 2-5 2.4.3 Wellhead Protection Areas ................................................................................................................................ 2-6 2.5 Land Cover and Land Use ........................................................................................................................................ 2-6 2.6 Lakes ................................................................................................................................................................................ 2-7 2.6.1 MDNR Public Waters ........................................................................................................................................... 2-7 2.6.2 MPCA Lake Classifications and Impaired Waters ..................................................................................... 2-7 2.6.2.1 MPCA Impaired Waters ............................................................................................................................. 2-8 2.6.3 Apple Valley Priority Lake Classification ....................................................................................................... 2-9 2.6.4 Apple Valley Priority Lakes ............................................................................................................................. 2-11 2.6.4.1 Alimagnet Lake .......................................................................................................................................... 2-11 2.6.4.2 Cobblestone Lake ..................................................................................................................................... 2-11 2.6.4.3 Farquar Lake ............................................................................................................................................... 2-12 2.6.4.4 Keller Lake ................................................................................................................................................... 2-12 2.6.4.5 Lac Lavon ..................................................................................................................................................... 2-13 2.6.4.6 Long Lake .................................................................................................................................................... 2-14 2.7 Wetlands ..................................................................................................................................................................... 2-14 2.8 Natural Communities and Rare Features ....................................................................................................... 2-15 2.9 Pollutant Sources ..................................................................................................................................................... 2-16 3.0 Assessment of Issues and Opportunities ............................................................................................................... 3-1 3.1 Water Quality ............................................................................................................................................................... 3-1 P:\Mpls\23 MN\19\23191345 City of Apple Valley SWMP\WorkFiles\Plan\Final\AV_SWMP_v3_10252018.docx i 3.1.1.1 National Pollutant Discharge Elimination System (NPDES) ........................................................ 3-3 3.1.2 Impaired Waters and Total Maximum Daily Load (TMDL) Issues ...................................................... 3-4 3.1.2.1 Alimagnet Lake TMDL ............................................................................................................................... 3-6 3.1.2.2 Long Lake and Farquar Lake ................................................................................................................... 3-6 3.1.2.3 Keller Lake TMDL ......................................................................................................................................... 3-7 3.1.2.4 East Lake TMDL ............................................................................................................................................ 3-7 3.1.2.5 Chlorides ......................................................................................................................................................... 3-8 3.1.3 Metropolitan Council Issues .............................................................................................................................. 3-8 3.1.4 Specific Water Quality Issues and Opportunities ..................................................................................... 3-8 3.1.4.1 Stormwater Pond Management ............................................................................................................ 3-8 3.1.4.2 Stormwater System Maintenance Programming ............................................................................ 3-9 3.1.4.3 Private Stormwater Facility Maintenance........................................................................................... 3-9 3.2 Water Quantity and Flood Risk ............................................................................................................................. 3-9 3.2.1 Floodplain Management and Flood Insurance Studies ...................................................................... 3-10 3.2.2 Intercommunity Drainage and Flow Rates ............................................................................................... 3-10 3.2.3 Specific Water Quantity Issues ...................................................................................................................... 3-11 3.3 Wetlands ..................................................................................................................................................................... 3-11 3.3.1 Wetland and Shoreland Buffers .................................................................................................................... 3-12 3.3.2 City Wetland Classification and Management ........................................................................................ 3-12 3.3.3 Aquatic Invasive Species (AIS) ....................................................................................................................... 3-13 3.4 Groundwater .............................................................................................................................................................. 3-13 3.4.1 Wellhead Protection .........................................................................................................................................