Trends in surface-water quality of an intermittent cold-desert stream

Abstract

Understanding the complex relationships among land use, geology, and climate in semiarid watersheds is essential to restoring degraded riparian areas and improving water quality. Muddy Creek in south-central Wyoming has been listed as impaired since 1996 by the US Environmental Protection Agency due to unstable stream channels and degraded riparian habitat. Water quality data collected from 1985 to 2006 were used to determine trends in surface-water quality. Flow analyses identified reductions in percents of flow duration intervals between the impaired stream's upper and lower boundary monitoring sites and in hydrograph peaks between pre- and post-best management practice (BMP) implementation. Following BMP implementation, reductions in specific conductivity, total dissolved solids, and turbidity among years were observed in the impaired stream section. Linking water quality improvements to specific BMPs is difficult; however results strongly suggest that positive trends are correlated to BMPs that stabilized stream channels and improved the condition of riparian areas. Naturally erosive conditions in the basin along with anthropogenic impacts elevate the importance of BMP implementation and a long-term monitoring program. Both are needed to evaluate the effectiveness of improvement efforts and to help resource managers develop practical watershed improvement management strategies so that optimum conditions in Muddy Creek basin can be achieved.