1 Water Quality Condition of Perennial Streams and Rivers in the Bighorn and Yellowstone Basins Water Quality Condition of Perennial Streams and Rivers in the Bighorn and Yellowstone Basins Results of the 2010 Bighorn/Yellowstone Probabilistic Survey Wyoming Department of Environmental Quality – Water Quality Division Document #14-0586, July 2014 2 Water Quality Condition of Perennial Streams and Rivers in the Bighorn and Yellowstone Basins Water Quality Condition of Perennial Streams and Rivers in the Bighorn and Yellowstone Basins Results of the 2010 Bighorn/Yellowstone Probabilistic Survey By Eric G. Hargett and Jeremy R. ZumBerge Document #14-0586 July 2014 Wyoming Department of Environmental Quality Water Quality Division – Watershed Protection Program 122 W. 25th St., Cheyenne, Wyoming 82002 i Water Quality Condition of Perennial Streams and Rivers in the Bighorn and Yellowstone Basins Table of Contents EXECUTIVE SUMMARY ....................................................................................................................................................... 1 INTRODUCTION AND OBJECTIVES ................................................................................................................................ 3 PROBABILISTIC SURVEYS AND WYOMING’S INTEGRATED REPORT ..................................................................... 4 STUDY AREA ........................................................................................................................................................................ 5 SURVEY DESIGN ................................................................................................................................................................. 7 DATA COLLECTION ............................................................................................................................................................ 8 SETTING EXPECTATIONS OF STREAM AND RIVER CONDITION .............................................................................. 9 INDICATORS OF BIOLOGICAL CONDITION ........................................................................................................... 9 INDICATORS FOR DRINKING WATER SUITABILITY AND HUMAN HEALTH CONDITION ............................ 10 STRESSORS TO BIOLOGICAL CONDITION ........................................................................................................... 13 CHEMICAL STRESSORS ......................................................................................................................................... 14 PHYSICAL STRESSORS ........................................................................................................................................... 17 RANKING OF STRESSORS ............................................................................................................................................. 19 Relative Extent ........................................................................................................................................................ 20 Relative Risk ............................................................................................................................................................. 20 DATA ANALYSIS .............................................................................................................................................................. 20 2010 STREAM FLOWS ................................................................................................................................................... 20 RESULTS ............................................................................................................................................................................. 21 EXTENT OF RESOURCE .............................................................................................................................................. 21 BIOLOGICAL CONDITION ........................................................................................................................................ 21 DRINKING WATER SUITABILITY AND HUMAN HEALTH CONDITION .............................................................. 27 PHYSICOCHEMICAL STRESSORS TO BIOLOGICAL CONDITION ..................................................................... 27 NUTRIENTS ............................................................................................................................................................... 27 SALINITY ................................................................................................................................................................... 33 SELENIUM ................................................................................................................................................................. 33 TOTAL SUSPENDED SOLIDS ................................................................................................................................. 33 CHLORIDE, pH and SULFATE ................................................................................................................................ 33 ARSENIC, CADMIUM and ZINC ........................................................................................................................... 33 PHYSICAL STRESSORS TO BIOLOGICAL CONDITION ....................................................................................... 33 RIPARIAN DISTURBANCE ....................................................................................................................................... 33 CHANNEL INSTABILITY .......................................................................................................................................... 34 RANKING OF STRESSORS ........................................................................................................................................ 34 DISCUSSION ..................................................................................................................................................................... 34 ii Water Quality Condition of Perennial Streams and Rivers in the Bighorn and Yellowstone Basins RECOMMENDATIONS .................................................................................................................................................... 42 ACKNOWLEDGMENTS .................................................................................................................................................. 43 REFERENCES ...................................................................................................................................................................... 43 Figures Figure 1 – Bioregions; national parks, wilderness and the Wind River Reservation; and selected municipalities of the Bighorn/Yellowstone Superbasin. .............................................................................................. 6 Figure 2 – Target, non-target, access denied and inaccessible sites evaluated as part of the Bighorn/Yellowstone Superbasin probabilistic survey including HUC 8 clusters; municipalities; and national parks, wilderness and the Wind River Reservation. ................................................................................................. 22 Figure 3 – Estimated target stream and river length relative to access denied, inaccessible and non-target lengths at the Bighorn/Yellowstone Superbasin and HUC 8 cluster scales based on 77 evaluated sites. Error bars represent the 95% confidence intervals. ................................................................................................. 26 Figure 4 – Biological condition of targeted perennial streams and rivers in the Bighorn/Yellowstone Superbasin based on results from the Wyoming Stream Integrity Index (WSII). Error bars represent the 95% confidence intervals. ............................................................................................................................................. 28 Figure 5 - Biological condition of targeted perennial streams and rivers in the Bighorn/Yellowstone Superbasin based on results from the Wyoming River InVertebrate Prediction And Classification System (WY RIVPACS). Error bars represent the 95% confidence intervals ................................................................... 29 Figure 6 - Biological condition of targeted perennial streams and rivers in the Bighorn/Yellowstone Superbasin based on WDEQ/WQD’s aquatic life use matrix. Error bars represent the 95% confidence intervals. ............................................................................................................................................................................ 30 Figure 7 – Most-disturbed condition relative extent (% stream length) of chemical and physical stressors to biological condition at the Bighorn/Yellowstone Superbasin and HUC 8 Cluster scales. Error bars represent the 95% confidence intervals. ....................................................................................................................................... 35 Figure 8 - Relative risk values of chemical and physical stressors to biological condition at the Bighorn/Yellowstone Superbasin scale. Error bars represent the 95% confidence intervals. ........................ 36 Figure 9 - Biological condition (top) of perennial streams and rivers (by percentage of respective stream length) and relative extents (bottom) of stressors common to the Bighorn/Yellowstone