The challenges of integrating groundwater in a significant way into California’s water supply portfolio
Bachand & Associates
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California’s unprecedented drought is very likely sign of California’s water future under climate change: longer drought cycles, less reliable snow pack water supplies, higher temperatures and greater reliance on groundwater. The current drought has accelerated groundwater overdraft throughout the state, increased the cost and value of water for farmers, resulted in farmers moving to high value crops, hardened agricultural water demand despite less reliable water supplies, and perhaps most importantly focused the California public on the looming water challenges in the State. California has begun to take action by passing the Sustainable Groundwater Management Act (SGMA) to protect groundwater resources and by making resources available to address the drought. Nevertheless, in the coming decades California will likely face increased challenges in meeting environmental, urban and agricultural water demand because of a number of factors: climate change will likely increase inter- and intra-annual variability in precipitation and move more precipitation from snow to rain in the Sierra Nevada mountains. Combined with increased temperatures and increased summer crop ET demands these hydro-climatic changes will create greater asynchronicity between water supply and agricultural delivery schedules. These challenges will require a re-imagining and perhaps a re-engineering of California’s water system. One potential tool for addressing this challenge is greater reliance on conjunctive use, leveraging private agricultural acreage throughout the Central valley to capture release flows from reservoirs for storage in groundwater reservoirs. The concept of using agricultural lands to capture excess flood flows has been gaining interest and acceptance in California. Challenges associated with this approach include not only technical challenges associated with developing BMPs, strategies and infrastructure for capturing flood and stormwater flows but also challenges associated with integrating flood capture BMPs with farming BMPs to protect crop yields and agricultural profits at economically sustainable levels and with implementing practices in ways that are legally consistent with State water laws, identified beneficial uses and future groundwater sustainability plans developed to comply with SGMA. These questions being currently addressed under several research efforts discussed here are the foundation for a future in which groundwater becomes a more critical and integrated component of California’s water portfolio.