Crow Wing River Watershed TMDL (Wq-Iw8-45E)
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Crow Wing River Watershed TMDL Quantification of the pollutant reductions needed to improve lake and stream water quality impairments due to excess phosphorus, excess bacteria, or high water temperature. August 2014 wq-iw8-45e Authors and contributors: Emmons & Olivier Resources, Inc: Meghan Jacobson, PhD Pat Conrad Camilla Correll Luke Nolby Sean Marczewski Etoile Jensen Annie Weeks Bonnie Finnerty, MPCA Kevin Stroom, MPCA Mark Evenson, MPCA John Erdmann, PhD, PE, MPCA Doug Kingsley and Mike Kelly, Park Rapids MN DNR-Fisheries Darrin Hoverson, Park Rapids MN DNR-Ecological and Water Resources (Area Hydrologist) Anne Oldakowski, Wadena SWCD Melissa Barrick, Crow Wing SWCD Julie Kingsley and Melissa Koebernick, Hubbard SWCD Sibley Lake Assocation Mayo Lake Association Blueberry Lake Association Twin Lakes Association Crow Wing River Watershed TMDL • August 2014 Minnesota Pollution Control Agency Table of Contents List of Figures .................................................................................................................................. i List of Tables ................................................................................................................................. iv List of Acronyms .......................................................................................................................... vii TMDL SUMMARY TABLE ......................................................................................................... ix EXECUTIVE SUMMARY .......................................................................................................... xv 1 PROJECT OVERVIEW ......................................................................................................... 1 1.1 Purpose ............................................................................................................................. 1 1.2 Identification of Waterbodies ........................................................................................... 1 1.3 Priority Ranking ............................................................................................................... 3 1.4 Description of the Impairments and Stressors.................................................................. 3 1.4.1 Lake Eutrophication .................................................................................................. 3 1.4.2 Stream E. coli ............................................................................................................ 3 1.4.3 Stream Dissolved Oxygen......................................................................................... 3 1.4.4 Stream Macroinvertebrate Bioassessment ................................................................ 4 2 APPLICABLE WATER QUALITY STANDARDS ............................................................. 8 2.1 Designated Use ................................................................................................................. 8 2.2 Lakes ................................................................................................................................ 8 2.3 Streams ............................................................................................................................. 9 2.3.1 Numeric Targets........................................................................................................ 9 2.3.2 Numeric Standards .................................................................................................. 16 3 WATERSHED DESCRIPTION ........................................................................................... 17 3.1 Lakes .............................................................................................................................. 17 3.2 Streams ........................................................................................................................... 18 3.3 Subwatersheds ................................................................................................................ 18 3.4 Land Cover ..................................................................................................................... 27 3.5 Historic Water Quality Conditions ................................................................................. 30 3.5.1 Lakes ....................................................................................................................... 30 3.5.2 Streams .................................................................................................................... 31 3.6 Pollutant Source Summary ............................................................................................. 44 3.6.1 Phosphorus .............................................................................................................. 44 3.6.2 Heating Capacity ..................................................................................................... 52 3.6.3 Escherichia coli ...................................................................................................... 57 4 TMDL DEVELOPMENT ..................................................................................................... 84 Crow Wing River Watershed TMDL • August 2014 Minnesota Pollution Control Agency 4.1 Phosphorus ..................................................................................................................... 84 4.1.1 Loading Capacity .................................................................................................... 84 4.1.2 Load Allocations ..................................................................................................... 89 4.1.3 Wasteload Allocations ............................................................................................ 89 4.1.4 Margin of Safety ..................................................................................................... 91 4.1.5 Seasonal Variation and Critical Conditions ............................................................ 91 4.1.6 Future Growth Considerations ................................................................................ 92 4.1.7 TMDL Summary ..................................................................................................... 94 4.1.8 TMDL Baseline Years .......................................................................................... 103 4.2 Temperature ................................................................................................................. 104 4.2.1 Loading Capacity .................................................................................................. 104 4.2.2 Load Allocations ................................................................................................... 105 4.2.3 Wasteload Allocations .......................................................................................... 105 4.2.4 Margin of Safety ................................................................................................... 105 4.2.5 Seasonal Variation and Critical Conditions .......................................................... 106 4.2.6 Reserve Capacity and Future Growth ................................................................... 106 4.2.7 TMDL Summary ................................................................................................... 108 4.2.8 TMDL Baseline Years .......................................................................................... 111 4.3 Escherichia coli ............................................................................................................ 112 4.3.1 Loading Capacity .................................................................................................. 112 4.3.2 Load Allocations ................................................................................................... 113 4.3.3 Wasteload Allocations .......................................................................................... 113 4.3.4 Margin of Safety ................................................................................................... 114 4.3.5 Seasonal Variation and Critical Conditions .......................................................... 115 4.3.6 Reserve Capacity and Future Growth ................................................................... 115 4.3.7 TMDL Summary ................................................................................................... 117 4.3.8 TMDL Baseline Years .......................................................................................... 128 5 REASONABLE ASSURANCES ....................................................................................... 129 5.1 Non-regulatory ............................................................................................................. 129 5.2 Regulatory .................................................................................................................... 129 5.2.1 Regulated Construction Stormwater ..................................................................... 129 5.2.2 Regulated Industrial Stormwater .......................................................................... 129 5.2.3 Municipal Separate Storm Sewer System (MS4) Permits .................................... 129 5.2.4 Wastewater & State Disposal System (SDS) Permits .......................................... 130 Crow Wing River Watershed TMDL • August 2014 Minnesota Pollution Control Agency 5.2.5 Subsurface Sewage Treatment Systems Program (SSTS) ...................................