GIS analysis of the pre and post-diversion water balances in Owens Valley, California
Owens Valley, California is located at the western border of both the Basin and Range and Great Basin Provinces. The valley is hydrologically closed; the only outflow for ground and surface waters is evaporation to the atmosphere. Los Angeles Department of Water and Power (LADWP) began diverting water from Owens Valley in 1913 and has steadily increased the amount of water removed from the valley since then; LADWP has always assumed that the hydrologic system as it existed in 1913 was in equilibrium with modern climate. This study develops a geographical information systems (GIS) based model of Owens Valley to (1) estimate post-diversion mountain block recharge for southern Owens Valley to test the assumption of equilibrium between recharge and observed playa discharge, and (2) estimate equilibrium extent of pre-diversion Owens Lake based on modern climate. Results demonstrate that water managers may be overestimating mountain block recharge to the modern playa by 50% and that pre-diversion Owens Lake was not in hydrologic equilibrium with modern climate and was likely still shrinking due to late Holocene warming.
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