Climate Change and Groundwater Use Impacts to Groundwater and Spring Hydrology, Amargosa Desert, Nevada and Death Valley National Park, California

This project evaluates the affects of climate change, and to some degree groundwater pumping, on the magnitude and timing of changes in groundwater levels and spring discharge in the Amargosa Desert in southwest Nevada and a portion of Death Valley National Park in eastern California. This is important because, almost without exception, groundwater is the sole source of water for ecosystem and human needs in southern Nevada and Death Valley National Park. The research focused on how the groundwater flow system in the Amargosa Desert, Nevada and Furnace Creek area of Death Valley National Park will respond to climate change, and comparison of the magnitude of climate response to that of continued groundwater pumping. This research will assist in developing a quantitative understanding of groundwater-spring dynamics so that changes to aquatic ecosystems that depend on groundwater flow may be predicted. The U.S. Geological Survey transient groundwater model for the Death Valley Regional Flow System was used for this project. Impacts to the groundwater flow system corresponding to possible climate change scenarios were simulated by varying recharge in the model. Synthesized results of global circulation climate models downscaled to the Death Valley region indicate average temperature will increase by approximately 3.4°C and average precipitation will decline by approximately 0.33 millimeters per month during the 21st Century. Simulated groundwater head changes resulting from climate change relative to baseline 20th Century conditions ranged from an increase of 0.34 meters to a decline of 2 meters, depending on the recharge (climate) scenario. Simulated groundwater discharge changes relative to baseline conditions ranged from an increase of 369 m3/day to a decline of 2,130 m3/day. The primary conclusion of this project is that climate change will affect the Amargosa Desert and Death Valley groundwater system and will likely exacerbate conditions of limited water supply. However, local and regional groundwater pumping have and will continue to have much greater affect on the groundwater system. Even if climate change results in increased precipitation and recharge, groundwater decline will continue as a result of pumping in the Death Valley regional groundwater flow system.