Analysis and Management Plan for The Upper Ahnapee River Watershed Photo: Brian Forest January 2020 Prepared by: Door County Soil and Water Conservation Department Approved by Wisconsin Department of Natural Resources February 27, 2020 Accepted by the Door County Land Conservation Committee March 12, 2020 Table of Contents Executive Summary 1. Background ........................................................................................................................... 1 Location and Municipalities ....................................................................................... 1 Ahnapee Watershed……………………..………………………………………………..………………………….2 Bedrock ..................................................................................................................... 4 Glacial Geology .......................................................................................................... 6 Soils ........................................................................................................................... 7 Soil Associations ........................................................................................................ 8 Hydrologic Soil Groups ............................................................................................... 9 Wetlands ................................................................................................................. 11 Surface Water Resources ......................................................................................... 14 Ahnapee River – Above the Dam .............................................................................. 14 Forestville Millpond ................................................................................................. 14 Ahnapee River – Below the Dam ............................................................................... 15 Silver Creek .............................................................................................................. 15 Groundwater Resources ........................................................................................... 16 2. Land Use .............................................................................................................................. 18 Agriculture ............................................................................................................... 18 Woodlands .............................................................................................................. 25 Natural Areas ........................................................................................................... 26 Developed ............................................................................................................... 26 Transportation ......................................................................................................... 26 Industrial ................................................................................................................. 26 Wastewater Treatment Facility ................................................................................ 26 3. Model Results ...................................................................................................................... 29 Model Assumptions ................................................................................................. 32 Summary of Results ................................................................................................. 34 4. Surface Water Chemistry...................................................................................................... 36 Sampling Locations in 2017 Forestville Millpond Study .............................................. 36 Results ..................................................................................................................... 38 Total Suspended Solids ............................................................................................ 40 i Total Phosphorus ..................................................................................................... 40 Temperature ........................................................................................................... 41 Dissolved Oxygen ..................................................................................................... 44 pH ........................................................................................................................... 44 Chlorophyll-A .......................................................................................................... 47 Nitrogen ................................................................................................................. 47 Millpond Trophic Status ........................................................................................... 48 WDNR Wadeable Trend Reference Site .................................................................... 48 Future Monitoring…………………………………………………………………………………………………….49 5. Implementation of Agricultural Standards ............................................................................ 50 Chapter 23 of Door County Code ............................................................................. .50 Status of Chapter 23 Compliance ............................................................................ .50 6. Goals and Activities ............................................................................................................. .53 7. Monitoring and Evaluation .................................................................................................. .60 8. Fiscal Management ............................................................................................................. .65 9. Information and Education .................................................................................................. .70 References .................................................................................. ………………………………………..73 Figures 1-1 Door County Location and Municipalities………………………………………………………………………………………1 1-2 Ahnapee River Subwatersheds in Door County……………………………………………………………….…………..…2 1-3 Ahnapee River Watershed……………………………………..…………………………………………………..….……………..3 1-4 Generalized Bedrock Map……………………………………………………………………………………………….………….…4 1-5 Generalized Geologic Cross Section……………………………………………………………………………………………….5 1-6 Typical Karst Cross-Section with Common Solution Features…………………………………………….……………5 1-7 Late Wisconsin Glaciation Ice Lobes………………………………………………………………………………….……………6 1-8 Proglacial Lake Oshkosh………………………………………………………………………………………………………………..6 1-9 DEM of Current Ahnapee River Valley in Door County……………………………………………………….…………..6 1-10 General Soil Depth to Bedrock – Based on Mapped Soil Type………………………………….…………..………….7 1-11 General Soil Associations………………………………………………………………………………………………………………9 1-12 Distribution of Hydrologic Soil Groups…………………………………………………………………………………………11 1-13 Location and Classification of Wetlands…………………………………………………..………………………….……….12 1-14 Average Nitrate Levels per Section………………………………………………………………………………………………17 1-15 Percentage of Coliform Bacteria Detect per Section……………………………………………………………….…….17 2-1 Upper Ahnapee River Watershed Land Use…………………………………………………………………………….……19 2-2 Livestock, Cropland and Nutrient Management Coverage………………………………………………………..….21 2-3 Location of Soil Test Phosphorus Levels Reported in 2018 Nutrient Management Plans………………..22 2-4 Location of Cropland Adjacent to Surface Water………………………………………………………………………....24 2-5 Shallow Soils and Conduits to Groundwater………………………………………………………………………………..25 ii 2-6 Distribution of Sanitary Systems……………………………………………………………………………………………….…27 2-7 Village of Forestville Wastewater Treatment Facility…………………………………………………………………..28 3-1 Subwatersheds of the Upper Ahnapee River Watersheds………………………………………………….…………29 4-1 Upper Ahnapee River Sample Locations……………………………………………………………………………….………37 4-2 Millpond and Downstream Sample Locations……………………………………………………………………….…..…37 5-1 Distribution of Compliance with Chapter 23 Sites Inventoried Prior to 2018 Update……………………..51 Charts 1-1 Hydrologic Soil Groups………………………………………………………………….………………..…………………………..10 1-2 Distribution of Wetland Types……………………………………………………………………….………………………….…13 1-3 Distribution of Surface Water Resources in the Upper Ahnapee River Watersheds…..……………….….16 2-1 Summary of Watershed Land Use…………………………………………………………………………….……………..…..18 2-2 Summary of Soil Test Phosphorus Concentrations…………………………………………………….………………….23 4-1 Total Phosphorus at Upstream Sites - 2017……………………………………………………………….………………...42 4-2 Total Phosphorus at Millpond Site - 2017………………………………………………………………….…………………42 4-3 Temperature at Upstream Sites - 2017…………………………………………………………………….…………………..43 4-4 Temperature above the Dam - 2017………………………………………………………………….………………………...43 4-5 Dissolved Oxygen Concentrations in Upstream Samples - 2017…………………………………….…………..…45 4-6 Dissolved Oxygen Concentrations in Millpond Samples - 2017……………………………………….…………….46 4-7 Nitrogen Concentrations in Millpond Samples - 2017…………………………………………………….………….…47 4-8 Macroinvertebrate Index of Biotic Integrity – Station 153161………………………………………….…………..49 5-1 Distribution of Compliance with Chapter 23 on Sites Inventoried Prior to 2018 Update…………………52 Tables 1-1 2019 Water Quality Monitoring Data for Silver Creek…………………………………………………………….…….15 3-1 STEPL Land Use Input by Subwatershed………………………………………………………………………………….……30 3-2 STEPL Agricultural Input by Subwatershed……………………………………………………………………………….….30 3-3 STEPL Septic System