Contextualizing Water Budgets of Closed Basins in Arid Climates Through Integrated Physical Hydrologic and Hydrochemical Modeling: Clayton Valley, Nevada
Abstract
Located in the arid Great Basin of the Western United States, Clayton Valley (CV) is a circular 1300 km2 endorheic basin with a 70 km2 playa surface. CV is a regional topographic low with a playa elevation of 1400 m above sea level, 1300 m lower than surrounding basins. Evaporite brines below CV have been developed as a lithium resource since the early 1960s. The local hydrologic budget for CV has been imbalanced since the end of the last pluvial period, 12 Kyr. Average modern evapotranspiration estimates are two orders of magnitude higher than precipitation estimates within the watershed. Preliminary tritium data indicates little to no modern water in brines and streams within CV. In order to sustain the stable brine concentrations and yields seen after decades of pumping, groundwater (GW) must be a) releasing from pluvial storage into the GW budget, or b) flowing into the basin subsurficially through transboundary or regional flow paths. The mechanism of Li release/mobilization would be unique to either recharge scenario. Valley geometry and thermal hydrochemical data do not support an exclusively pluvial GW source, indicating an external source of water to the basin. Regional interbasin flow, while widely accepted as a primary component of the GW flow system of the Great Basin, has not been convincingly tied to the GW system of CV. Original and published hydrologic, hydrophysical and hydrochemical observations are used to: inform three-dimensional GW flow models of the immediate CV region; identify CV's position within the regional GW flow system; and define its contributing watershed, which is likely 2-3 times the area of CV. Numerical GW flow models for CV and its contributing areas are developed based on existing USGS Great Basin GW flow models and refined through the unification of physical hydrologic and hydrochemical data. In order to develop a realistic and complete picture of the hydrologic budget of CV, this study takes hydrologic and hydrochemical data as concomitant, unlike previous physical or chemistry-based hydrologic models of the valley. Findings from numerical models of CV may be applicable academically to integrated hydrologic studies of closed basins in regional flow; economically to brine production estimations and predictions; and legally in watershed delineation investigations and management.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.H53C1718G
- Keywords:
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- 1812 Drought;
- HYDROLOGYDE: 1829 Groundwater hydrology;
- HYDROLOGYDE: 1830 Groundwater/surface water interaction;
- HYDROLOGYDE: 1880 Water management;
- HYDROLOGY