Madison Sediment and Temperature TMDLs and Water Quality Improvement Plan September 2020 Steve Bullock, Governor Shaun McGrath, Director DEQ Document Number M06-TMDL-01bF The latest controlled version of this document is located on the DEQ website (http://deq.mt.gov). Printed copies are not controlled. Document users are responsible for ensuring printed copies are valid prior to use. Prepared by: Water Quality Planning Bureau Watershed Protection Section Contributors: Water Quality Planning Bureau Watershed Protection Section Christy Meredith, Sediment and Temperature Project Manager Kristy Fortman, Previous Sediment and Temperature Project Manager Christina Staten, Project Coordinator Cover Photo: West Fork Madison River Photo by: Montana Department of Environmental Quality Montana Department of Environmental Quality Water Quality Planning Bureau 1520 E. Sixth Avenue P.O. Box 200901 Helena, MT 59620-0901 Suggested citation: Montana DEQ. 2020. Madison Sediment and Temperature TMDLs and Water Quality Improvement Plan. Helena, MT: Montana Dept. of Environmental Quality. ACKNOWLEDGEMENTS DEQ would like to acknowledge multiple people and entities for their contributions in the development of the TMDLs contained in this document. The Madison Conservation District provided support throughout the Madison TMDL planning and development process, aiding with identification of stakeholders and assisting with coordination of stakeholder meetings, public outreach and education, review of draft TMDL document sections, and providing local knowledge of water quality conditions in the watershed. DEQ thanks David Laufenberg, Madison Conservation Programs Coordinator, and Ethan Kunard, the former Water Programs Manager. The Madison Conservation District will also be involved in implementing many of the water quality improvement recommendations contained in this document. Madison Sediment and Temperature TMDLs – Table of Contents TABLE OF CONTENTS Abbreviations and Acronyms ........................................................................................................................ x How This Document is Organized and What it Contains ............................................................................ xii Part 1 – Introductory Information .......................................................................................................... xii Part 2 – TMDL Components .................................................................................................................... xii Part 3 – Water Quality Recommendations .............................................................................................xiii Individual Stream Summaries ................................................................................................................. DS-1 TMDL Document Summary ..................................................................................................................... DS-1 Part 1 Introductory Information .............................................................................................................. P1-1 1.0 Project Overview .................................................................................................................................. 1-1 1.1 Why We Write TMDLs ...................................................................................................................... 1-2 1.2 Water Quality Impairments and TMDLs Addressed by this Document ........................................... 1-2 1.3 Completed TMDLs and Future TMDL Development ........................................................................ 1-5 2.0 Madison TMDL Planning Area Description .......................................................................................... 2-1 2.1 Physical Characteristics .................................................................................................................... 2-1 2.1.1 Location ..................................................................................................................................... 2-1 2.1.2 Topography ............................................................................................................................... 2-2 2.1.3 Climate ...................................................................................................................................... 2-3 2.1.4 Hydrology .................................................................................................................................. 2-6 2.1.5 Geology and Soils ...................................................................................................................... 2-7 2.2 Ecological Profile .............................................................................................................................. 2-9 2.2.1 Ecoregions ................................................................................................................................. 2-9 2.2.2 Land Cover .............................................................................................................................. 2-10 2.23 Fire History ............................................................................................................................... 2-11 2.2.4 Fish Distribution ...................................................................................................................... 2-11 2.3 Social Profile ................................................................................................................................... 2-12 2.3.1 Population Density .................................................................................................................. 2-13 2.3.2 Land Management .................................................................................................................. 2-13 2.2.3 Agricultural Land Use .............................................................................................................. 2-14 2.3.4 Road Networks ........................................................................................................................ 2-15 2.3.5 Wastewater Discharges .......................................................................................................... 2-16 3.0 Montana Water Quality Standards ...................................................................................................... 3-1 3.1 Stream Classifications and Designated Beneficial Uses ................................................................... 3-1 3.2 Numeric and Narrative Water Quality Standards ............................................................................ 3-3 09/22/20 FINAL i Madison Sediment and Temperature TMDLs – Table of Contents 3.3 Nondegradation Provisions .............................................................................................................. 3-3 4.0 Defining TMDLs and Their Components .............................................................................................. 4-1 4.1 Developing Water Quality Targets ................................................................................................... 4-2 4.2 Quantifying Pollutant Sources ......................................................................................................... 4-2 4.3 Establishing the Total Allowable Load ............................................................................................. 4-3 4.4 Determining Pollutant Allocations ................................................................................................... 4-4 4.5 Implementing TMDL Allocations ...................................................................................................... 4-5 Part 2 TMDL Components ........................................................................................................................ P2-1 5.0 Sediment TMDL Components .............................................................................................................. 5-1 5.1 Effects of Excess Sediment on Beneficial Uses ................................................................................ 5-1 5.2 Sediment TMDL Stream Segments .................................................................................................. 5-1 5.3 Information Sources and Assessment Methods .............................................................................. 5-4 5.4 Water Quality Targets and Target Development Rationale ............................................................ 5-4 5.4.1 Targets Summary ...................................................................................................................... 5-4 5.4.2 Target Development Rationale ................................................................................................. 5-6 5.4.3 Existing Condition and Comparison to Water Quality Targets ............................................... 5-10 5.5 Source Assessment and Quantification ......................................................................................... 5-35 5.5.1 Eroding Streambank Sediment Assessment ........................................................................... 5-36 5.5.2 Unpaved Road Sediment Assessment .................................................................................... 5-38 5.5.3 Upland Sediment Assessment ................................................................................................ 5-40 5.5.4 Source Assessment Summary ................................................................................................