Wyoming’s 2016/2018 Integrated 305(b) and 303(d) Report Prepared by: Wyoming Department of Environmental Quality Water Quality Division Watershed Section Document # 18-0111 Wyoming’s Final 2016/2018 Integrated 305(b) and 303(d) Report Table of Contents Executive Summary ........................................................................................................................... vii 1.0 Introduction .................................................................................................................................. 1 1.1 Section 305(b) Requirements ..................................................................................................... 1 1.2 Section 303(d) Requirements ..................................................................................................... 1 2.0 Determining Surface Water Quality Condition .................................................................................. 1 2.1 Data Requirements .................................................................................................................... 2 Credible Data .............................................................................................................................. 2 Wyoming’s Weight of Evidence Approach ...................................................................................... 3 Historic Data ............................................................................................................................... 3 2.2 Designated Uses and Classifications ............................................................................................ 3 2.3 Designated Use Support Determinations ..................................................................................... 5 2.4 USEPA Categorization ................................................................................................................ 5 3.0 Surface Water Quality Monitoring ................................................................................................... 7 3.1 Wyoming’s Surface Water Monitoring Program ............................................................................ 7 Wyoming’s Probabilistic Rotating Basin Surveys ............................................................................. 7 3.2 Monitoring by Conservation Districts ........................................................................................... 8 4.0 TMDL Prioritization ........................................................................................................................ 8 4.1 Long-Term Vision Strategy ......................................................................................................... 9 Water Quality Prioritization Framework ............................................................................................. 9 5.0 Wyoming’s Nonpoint Source Program ........................................................................................... 17 6.0 Emerging Surface Water Quality Issues ........................................................................................ 17 Methylmercury .......................................................................................................................... 17 Climate Change ......................................................................................................................... 18 7.0 Public Participation ...................................................................................................................... 18 8.0 Basin Descriptions and Surface Water Quality Summaries .............................................................. 18 8.1 Bear River Basin ...................................................................................................................... 19 Upper Bear River Sub-basin (HUC 16010101) .............................................................................. 19 Central Bear River Sub-basin (HUC 16010102) ............................................................................ 21 8.2 Belle Fourche River Basin ......................................................................................................... 24 Upper Belle Fourche Sub-basin (HUC 10120201) ......................................................................... 25 8.3 Bighorn River Basin .................................................................................................................. 28 Upper Wind Sub-basin (HUC 10080001) ...................................................................................... 29 Little Wind Sub-basin (HUC 10080002) ....................................................................................... 32 Popo Agie Sub-basin (HUC 10080003) ........................................................................................ 33 Lower Wind Sub-basin (HUC 10080005)...................................................................................... 37 Badwater Creek Sub-basin (HUC 10080006) ................................................................................ 38 Upper Bighorn Sub-basin (HUC 10080007) .................................................................................. 38 Nowood Sub-basin (HUC 10080008) ........................................................................................... 42 Greybull Sub-basin (HUC 10080009) ........................................................................................... 44 Bighorn Lake Sub-basin (HUC 10080010) .................................................................................... 47 Dry Creek Sub-basin (HUC 10080011) ........................................................................................ 49 North Fork Shoshone River Sub-basin (HUC 10080012) ............................................................... 50 Shoshone River Sub-basin (HUC 10080014) ................................................................................ 51 Little Big Horn River Sub-basin (HUC10080016)........................................................................... 55 8.4 Cheyenne River Basin .............................................................................................................. 56 Antelope Creek Sub-basin (HUC 10120101) ................................................................................. 56 Upper Cheyenne Sub-basin (HUC 10120103) ............................................................................... 57 Angostura Reservoir Sub-basin (HUC10120106) .......................................................................... 59 Beaver Creek Sub-basin (HUC 10120107) ................................................................................... 60 8.5 Green River Basin .................................................................................................................... 61 Upper Green Sub-basin (HUC 14040101) .................................................................................... 61 New Fork Sub-basin (HUC 14040102) ......................................................................................... 64 Page ii Wyoming’s Final 2016/2018 Integrated 305(b) and 303(d) Report Slate Creek Sub-basin (HUC 14040103) ...................................................................................... 66 Big Sandy Sub-basin (HUC 14040104) ........................................................................................ 66 Bitter Creek Sub-basin (HUC 14040105) ...................................................................................... 68 Flaming Gorge Sub-basin (HUC 14040106) .................................................................................. 70 Blacks Fork Sub-basin (HUC 14040107) ...................................................................................... 71 8.6 Little Missouri River Basin ......................................................................................................... 74 8.7 Little Snake River Basin ............................................................................................................ 75 Little Snake Sub-basin (HUC 14050003) ...................................................................................... 75 Muddy Creek Sub-basin (HUC 14050004) .................................................................................... 78 8.8 Niobrara River Basin ................................................................................................................ 82 Niobrara Headwaters Sub-basin (HUC 10150002) ........................................................................ 82 8.9 North Platte River Basin ........................................................................................................... 83 Upper North Platte Sub-basin (HUC 10180002) ........................................................................... 84 Pathfinder-Seminoe Sub-basin (HUC 10180003) .......................................................................... 89 Medicine Bow Sub-basin (HUC 10180004) ................................................................................... 89 Little Medicine Bow Sub-basin (HUC 10180005) ........................................................................... 91 Sweetwater Sub-basin (HUC 10180006) ...................................................................................... 93 Middle North Platte Sub-basin (HUC 10180007) ........................................................................... 95 Glendo Sub-basin (HUC 10180008) ............................................................................................