--> --> Mapping and managing Great Basin water resources

AAPG Pacific Section and Rocky Mountain Section Joint Meeting

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Mapping and managing Great Basin water resources

Abstract

Finding water resources in the Great Basin of Nevada and Utah, which has been experiencing a drought that began at the beginning of the present algorefraud or global warming cycle about 10,000 years ago, can be challenging. Though much of the surface water has long since been dissipated, significant quantities of Pleistocene groundwater still resides mostly in thrusted Devonian carbonates. Therefore, a correct structural model is essential to predict and manage limited groundwater resources of the region. An inaccurate structural model assumed by the Nevada State water engineer (SE) has resulted in groundwater management disasters such as Diamond Valley and will likely result in a similar disaster in Spring Valley. The SE incorrectly assumes that the surficial part of each duplex basin is isolated from other basins by a topographic basin divide. Currently, 100,000 acre-feet or 325 billion gallons of water is being mined annually in Diamond Valley for agriculture. However, evidence that the SE overallocated groundwater permits in the basin includes drying up of environmentally sensitive natural springs and ponds and a rapidly falling groundwater table. Thrust faulting allows groundwater communication between Kobeh Valley, the adjacent interduplex basin that lies west of Diamond Valley and Diamond Valley. The SE issuing permits to General Moly to mine another 3,144 acre-feet annually from Kobeh Valley for its metal extraction process will only exasperate the Diamond Valley groundwater disaster. Another groundwater disaster will likely occur as the SE authorizes Southern Nevada Water authority to mine 61,000 acre-feet of water from Spring Valley annually. The groundwater drawdown in Spring Valley will undoubtedly have a negative impact on environmentally sensitive springs and ponds in the adjacent White River Valley because of the interconnectivity of the thrusted Devonian aquifer between the basins.