Authors: Jacqueline Rogers*, Santa Clara University, Iris T Stewart, Santa Clara University, Anne Graham, Santa Clara University
Topics: Water Resources and Hydrology, Human-Environment Geography, Environment
Keywords: stream flow, drought impacts, stream temperatures, water security, salmon, sustainability
Session Type: Paper
Presentation File: No File Uploaded
The record-breaking 2014-2016 California drought, emblematic of the more frequent and extreme climatic events projected under climate change, highlighted the complex challenges of supplying water for competing uses in water-limited regions during times of severe shortages. The Tuolumne watershed in Central California supplies water to urban users in the San Francisco Bay Area and agricultural regions in the Central Valley, while also constituting important habitat for Chinook salmon. This study examines the equity of drought impacts among the agricultural, and different urban sectors, and environmental needs. Analyzing the relative magnitude of flow and storage in different parts of the watershed during 'no drought', 'moderate drought', and 'severe drought conditions during the 2008 - 2018 study period, we found that 'moderate' and 'severe' drought events affected sections of Tuolumne watershed in profoundly different ways. Water storage and supplies in the upper watershed for urban users in economically well-off areas were not affected by drought, while supplies to agricultural and urban users in the Central Valley were curtailed by about 30%, and flow reductions in the lower portion of the watershed important to salmon migration amounted to 85-90% during 'severe' drought conditions. Concurrent with the water scarcity, stream temperatures in the lower watershed were significantly warmer, and salmon populations lower during 'moderate' and 'severe drought'. We outline integrative drought-preparation strategies for California and other water-limited regions that prioritize water security through an equitable and sustainable distribution of the available water resources while minimizing the impact on human water supplies and ecosystems.
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