Hydrogeology of desert springs in the Panamint Range,California, USA: Identifying the sources and amount of recharge that support spring flow |
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| Authors: | Carolyn L Gleason Marty D Frisbee Laura K Rademacher Donald W Sada Zachary P Meyers |
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| Institution: | 1. Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana
Genesis Engineering and Redevelopment, Lodi, California;2. Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana;3. Department of Geological and Environmental Sciences, University of the Pacific, Stockton, California;4. Division of Hydrologic Sciences, Desert Research Institute, Reno, Nevada |
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| Abstract: | Despite its location in the rain shadow of the southern Sierra Nevada, the Panamint Range hosts a complex mountain groundwater system supporting numerous springs which have cultural, historical, and ecological importance. The sources of recharge that support these quintessential desert springs remain poorly quantified since very little hydrogeological research has been completed in the Panamint Range. Here we address the following questions: (i) what is the primary source of recharge that supports springs in the Panamint Range (snowmelt or rainfall), (ii) where is the recharge occurring (mountain-block, mountain-front, or mountain-system) and (iii) how much recharge occurs in the Panamint Range? We answer questions (i) and (ii) using stable isotopes measured in spring waters and precipitation, and question (iii) using a chloride mass-balance approach which is compared to a derivation of the Maxey–Eakin equation. Our dataset of the stable isotopic composition (δ18O and δ2H) of precipitation is short (1.5 years), but analyses on spring water samples indicate that high-elevation snowmelt is the dominant source of recharge for these springs, accounting for 57 (±9) to 79 (±12) percent of recharge. Recharge from rainfall is small but not insignificant. Mountain-block recharge is the dominant recharge mechanism. However, two basin springs emerging along the western mountain-front of the Panamint Range in Panamint Valley appear to be supported by mountain-front and mountain-system recharge, while Tule Spring (a basin spring emerging at the terminus of the bajada on the eastern side of the Panamint Range) appears to be supported by mountain-front recharge. Calculated recharge rates range from 19 mm year?1 (elevations < 1000 mrsl) to 388 mm year?1 (elevations > 1000 mrsl). The average annual recharge is approximately 91 mm year?1 (equivalent to 19.4 percent of total annual precipitation). We infer that the springs in the Panamint Range (and their associated ecosystems) are extremely vulnerable to changes in snow cover associated with climate change. They are heavily dependent on snowmelt recharge from a relatively thin annual snowpack. These findings have important implications for the vulnerability of desert springs worldwide. |
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| Keywords: | climate change crenobiontic Death Valley Desert springs mountain recharge Panamint Range snowmelt recharge sources of recharge spring vulnerability stable isotopes |
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