Groundwater is instrumental in slaking California's thirst. In average years, underground basins, known as aquifers, supply about 35% of the water used by the state's cities and farms, and in drought years, that figure can jump to 60% or higher.
Many areas of the state rely exclusively on groundwater for their supplies, while other areas use groundwater to supplement their surface supplies or to meet needs when surface water is not available.
California has a long history of managing groundwater resources through locally controlled programs. While many of these programs have been very effective, the array of challenges on the horizon will demand even more of local agencies and require a greater commitment to sustainable management.
As surface water deliveries continue to be constrained, California is relying more and more on groundwater to meet needs. The shift to greater reliance makes effective management a critical challenge as the state works to implement historic legislation enacted in 2009 to improve water supply reliability and ecosystem health.
Locally controlled groundwater management is effective because it is best able to respond to the particular circumstances of – and significant differences in – each groundwater basin. Local expertise and direct reliance on the resource ensures immediate response to problems and trends, and provides the strongest basis for collaborative regional approaches.
Groundwater management plans developed under AB 3030, SB 1938 and the Integrated Regional Water Management Planning Act offer prime opportunities to enhance effective management and incorporate strategies that can help address the potential consequences of a large-scale shift to groundwater, whether cyclical or permanent.
Local agencies with these plans and other local management strategies in place are stepping forward to monitor groundwater elevation levels to help track seasonal and long-term trends in groundwater basins as required by the 2009 legislation.
Given the significant differences in groundwater basins, ACWA believes the one-size-fits-all approach of statewide regulation would be counterproductive. But that is not to say there is no role for the state. ACWA believes the state should encourage and support local management by embracing polices that reflect California’s hydrologic diversity, by working collaboratively with local agencies to address impediments and by incentivizing the expansion of sustainable practices.
Ultimately, for sustainable groundwater management to succeed, California must also invest in conveyance improvements in the Delta, additional surface storage and groundwater storage to optimize both water supply reliability and ecosystem health, and substantial investments in local water resources development.
Read about ACWA's landmark policy document, "Sustainability from the Ground Up: A Framework for Groundwater Management in California."