Tuesday, October 14, 2008 : 1:30 p.m.
Impacts of Non-Sustainable Ground Water Use on Walker Lake
Walker Lake is a terminal desert lake located in west-central Nevada , whose watershed is 11,110 square km, and its headwaters are in the eastern Sierra Nevada range. The headwater flows are primarily due to snowmelt and are approximately 403 million m3/yr. Approximately 396 million m3/year of water is diverted from the Walker River and its tributaries to sustain agricultural activity in the watershed, which is the most productive agricultural area in the State of Nevada. These diversions are not completely consumptive, so some return flows do migrate back to the main channel, resulting in an average yearly flow to Walker Lake of approximately 135 million m3/yr. Walker Lake’s volume has decreased from 11 billion m3 in the 1880s, to a volume of 1.8 billion m3 at the end of 2002. During this time the Lake's salt concentration (expressed in TDS) has risen from 2,560 mg/l to over 13,000 mg/l in 2002. Under current hydrologic conditions the volume of water in Walker Lake will decrease to a transient steady state volume of 924 million m3, and have a corresponding TDS concentration of 35,200 mg/l. For these conditions, the lake would have little recreational value, and the Lake would become uninhabitable for most of its current aquatic species. Ground water use was not a significant component of the hydrologic balance within the Walker Basin until the 1960s when supplemental ground water rights were granted to water users that held more junior water rights. This paper explores the impact that this ground water management strategy has had on flows to Walker Lake and predictions of how altering this strategy will impact the condition of Walker Lake, ground water levels within the basin, and agricultural production within the Walker River watershed.
John C. Tracy, Ph.D., University of Idaho Dr. Tracy is Director of the Idaho Water Resources Research Institute at the University of Idaho. Dr. Tracy received his B.S. degree in Civil Engineering at Colorado State University in 1980, and his M.S. and Ph.D. degrees in Civil Engineering at the University of California at Davis in 1986 and 1989 respectively. He has also held academic positions at Kansas State University, South Dakota State University and the Desert Research Institute. Dr. Tracy has worked on numerous research projects and authored or co-authored over 70 technical publications in the areas of watershed planning, watershed restoration and the closed basin hydrology.