Upper and Lower Henry's Fork Total Maximum Daily Loads: Addendum

Upper and Lower Henry’s Fork Total Maximum Daily Loads: Addendum to the Upper Henry’s Fork Subbasin Assessment and TMDLs Final Department of Environmental Quality June 2010 - ii - June 2010 Upper and Lower Henry’s Fork Total Maximum Daily Loads: Addendum to the Upper Henry’s Fork Subbasin Assessment and TMDLs June 2010 Prepared by: Idaho Falls Regional Office Department of Environmental Quality 900 North Skyline Dr., Suite B Idaho Falls, ID 83402 - iii - June 2010 This page intentionally left blank for correct double-sided printing. - iv - June 2010 Acknowledgments Jim De Rito and Anne Marie Emery-Miller of the Henry’s Fork Foundation bestowed considerable knowledge of the watershed and assisted with obtaining land access. Troy Saffle, Jack Rainey, and Heather Bohac, all of the DEQ-Idaho Falls Regional Office, imparted extensive technical and field support, along with editorial reviews. Mark Shumar of DEQ-Technical Services is the author of the temperature TMDL sections and provided a great deal of technical assistance. Damon Keen with Idaho Fish and Game provided implementation and restoration project information. The Empey family allowed access to their private property on Duck Creek. Brad Higginson with the U.S. Forest Service (USFS) provided watershed improvement projects completed by the Forest Service in the subbasins. Members of the WAG generously donated their time and knowledge to the TMDL. Thank you all for contributing to the Upper and Lower Henry’s Fork TMDL. Cover photo of Icehouse Creek by Heather Bohac (DEQ) taken on September 24, 2008. - v - June 2010 This page intentionally left blank for correct double-sided printing. - vi - June 2010 Table of Contents Acknowledgments ..............................................................................................................................................v List of Tables.................................................................................................................................viii List of Figures ................................................................................................................................ ix Abbreviations, Acronyms, and Symbols ......................................................................................... x Executive Summary.......................................................................................................................................... xi Subbasin at a Glance .................................................................................................................... xi Key Findings .................................................................................................................................xiii 1. Introduction ................................................................................................................................................ 1 1.1 Background ..........................................................................................................................1 1.2 Idaho’s Role..........................................................................................................................2 1.3 Subbasin Characterization ...................................................................................................2 2. Water Quality Limited Assessment Units Occurring in the Subbasin.............................................. 5 2.1 About Assessment Units ......................................................................................................5 2.1.1 Listed Waters ...........................................................................................................6 2.2 Applicable Water Quality Standards ....................................................................................7 2.2.1 Beneficial Uses ........................................................................................................8 2.2.2 Criteria to Support Beneficial Uses ..........................................................................9 2.3 Pollutant/Beneficial Use Support Status Relationships......................................................10 2.3.1 Sediment ................................................................................................................10 2.3.2 Temperature...........................................................................................................11 2.3.3 Bacteria ..................................................................................................................12 3. Sources of Pollutants of Concern......................................................................................................... 13 3.1 Point Sources .....................................................................................................................13 3.2 Nonpoint Sources...............................................................................................................13 3.3 Pollutant Transport .............................................................................................................13 3.4 Data Gaps ..........................................................................................................................14 4. Permitting and Status of Water Quality Improvements..................................................................... 15 5. Total Maximum Daily Load..................................................................................................................... 17 5.1 Sediment TMDLs................................................................................................................18 5.1.1 In-stream Water Quality Targets............................................................................18 5.1.2 Load Capacity ........................................................................................................21 5.1.3 Estimates of Existing Pollutant Loads....................................................................21 5.1.4 Daily Sediment Load Allocations ...........................................................................22 5.1.5 Wasteload Allocations............................................................................................26 5.1.6 Load Allocations.....................................................................................................26 5.2 Temperature TMDLs ..........................................................................................................28 5.2.1 In-stream Water Quality Targets............................................................................29 5.2.2 Load Capacity ........................................................................................................38 5.2.3 Estimates of Existing Pollutant Loads....................................................................39 5.2.4 Wasteload Allocation..............................................................................................49 5.2.5 Load Allocation.......................................................................................................49 5.3 Bacteria TMDL ...................................................................................................................51 5.3.1 In-stream Water Quality Targets............................................................................52 5.3.2 Load Capacity ........................................................................................................53 5.3.3 Estimates of Existing Pollutant Loads....................................................................53 5.3.4 Waste Load Allocation ...........................................................................................53 5.3.5 Load Allocations.....................................................................................................53 5.4 Construction Storm Water and TMDL Wasteload Allocations ...........................................54 5.4.1 Construction Storm Water......................................................................................54 - vii - June 2010 5.4.2 The Construction General Permit (CGP) ...............................................................54 5.4.3 Storm Water Pollution Prevention Plan (SWPPP) .................................................54 5.4.4 Construction Storm Water Requirements ..............................................................54 5.5 Implementation Strategies..................................................................................................55 5.5.1 Time Frame............................................................................................................55 5.5.2 Approach................................................................................................................55 5.5.3 Responsible Parties ...............................................................................................55 5.5.4 Monitoring Strategy ................................................................................................56 5.5.5 Public Participation/Watershed Advisory Group (WAG) Activities.........................56 5.6 Conclusions........................................................................................................................57 References Cited.............................................................................................................................................. 59 Glossary............................................................................................................................................................

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