TMDL PolicyFinal and Guidance Rum River Watershed Required Language and Recommendations for all Total Maximum Daily Loads developed in Minnesota : Most of this information is already included in this document, but you should check it to ensure that you are usingTotal the most recent lMaximumanguage. Daily Load July 2017 wq-iw8-56e Authors and contributors: Aitkin County Janet Smude, Aitkin Soil and Water Conservation District Steve Hughes, Aitkin Soil and Water Conservation District Anoka County Jamie Schurbon, Project Manager Anoka Soil and Water Conservation District City of Cambridge Todd Schwab Todd Blank City of Ramsey Leonard Linton Bruce Westby City of Anoka Ben Nelson Crow Wing County Melissa Barrick, Crow Wing Soil and Water Conservation District Isanti County Holly Nelson Tiffany Determan, Isanti County Soil and Water Conservation District Mille Lacs Band of Ojibwe Perry Bunting Chad Weiss Mille Lacs County Susan Shaw, Mille Lacs Soil and Water Conservation District Sherburne County Dan Cibulka, Sherburne Soil and Water Conservation District Minnesota Board of Water Resources Dave Johnson Jason Weinerman Minnesota Department of Natural Resources Craig Wills Leslie George David Depaz Reid Northwick Rick Bruesewitz Rum River Watershed TMDL ii Minnesota Pollution Control Agency Minnesota Pollution Control Agency Bonnie Finnerty, Project Manager Chuck Johnson Chandra Henrich RESPEC Cindie McCutcheon Chris Lupo Bruce Wilson Lee Rosen Julie Blackburn Rum River Watershed TMDL iii Minnesota Pollution Control Agency Contents Contents ........................................................................................................................................... iv List of Tables ...................................................................................................................................... x List of Figures .................................................................................................................................. xiv TMDL Summary Table ...................................................................................................................... xx Acronyms ....................................................................................................................................... xxi Executive Summary ............................................................................................................................1 1 Project Overview ........................................................................................................................3 1.1 Purpose ................................................................................................................................................ 3 1.2 Identifying Waterbodies....................................................................................................................... 5 1.3 Priority Ranking .................................................................................................................................... 5 2 Applicable Water Quality Standards and Numeric Water Quality Targets .....................................7 2.1 E. coli Bacteria ...................................................................................................................................... 7 2.2 Dissolved Oxygen ................................................................................................................................. 7 2.3 Nutrients (Phosphorus) ........................................................................................................................ 7 3 Watershed and Waterbody Characterization ...............................................................................9 3.1 Historical/Legacy Perspectives ............................................................................................................. 9 3.2 Demographic Growth Projections ........................................................................................................ 9 3.3 Climate ................................................................................................................................................. 9 3.3.1 Characterization of Storm Events ....................................................................................... 13 3.3.2 Precipitation Variability: Wet and Dry Periods ................................................................... 14 3.3.3 Frost-Free Season Length .................................................................................................... 14 3.3.4 Evaporation ......................................................................................................................... 15 3.3.5 Climate Summary ................................................................................................................ 17 3.4 Watershed Characteristics ................................................................................................................. 17 3.4.1 Subwatersheds .................................................................................................................... 17 3.4.2 Land Cover .......................................................................................................................... 18 3.4.3 Soils ..................................................................................................................................... 22 3.4.4 Lake Characteristics ............................................................................................................ 23 3.4.4.1 Lake Eutrophication and Physical Characteristics ........................................................... 23 3.4.4.2 Lake Physical Characteristics ........................................................................................... 25 3.4.4.3 Shallow Lakes .................................................................................................................. 25 3.4.4.4 Deep Lakes ...................................................................................................................... 27 3.5 Current/Historic Water Quality .......................................................................................................... 28 3.5.1 Stream and Rum River Flows .............................................................................................. 28 Rum River Watershed TMDL iv Minnesota Pollution Control Agency 3.5.2 Water Quality ...................................................................................................................... 28 3.5.2.1 E. coli ............................................................................................................................... 29 3.5.2.2 Dissolved Oxygen ............................................................................................................ 29 3.5.2.3 Nutrients ......................................................................................................................... 33 3.6 HSPF Model Methodology ................................................................................................................. 35 3.6.1 Gathering and Developing Time-Series Data ...................................................................... 36 3.6.2 Characterizing and Segmenting the Watershed ................................................................. 36 3.6.3 Calibrating and Validating the HSPF Model ........................................................................ 37 3.7 Pollutant Source Summary ................................................................................................................. 38 3.7.1 E. coli ................................................................................................................................... 39 3.7.1.1 Permitted ........................................................................................................................ 40 3.7.1.2 Nonpermitted ................................................................................................................. 40 3.7.1.3 Potential Sources ............................................................................................................ 41 3.7.2 Dissolved Oxygen ................................................................................................................ 44 3.7.2.1 Permitted ........................................................................................................................ 45 3.7.2.2 Nonpermitted ................................................................................................................. 45 3.7.2.3 Potential Sources ............................................................................................................ 46 3.7.3 Nutrients ............................................................................................................................. 53 3.7.3.1 Permitted ........................................................................................................................ 54 3.7.3.2 Nonpermitted ................................................................................................................. 55 3.7.3.3 Potential Sources ............................................................................................................ 57 4 TMDL Development: E. coli, Dissolved Oxygen, and Lake Nutrients ............................................ 58 4.1 E. coli .................................................................................................................................................