HydroVis Water in the Bank – California’s Mission to Recharge Groundwater During Wet Years for Drought Resiliency by Azita Assadi, AECOM; Pete Dennehy, Montgomery & Associates; Meeta Pannu, Orange County Water District; Marcus Trotta, Sonoma Water
The winter of 2023 will be remembered by Californians for record shattering precipitation and snowfall. A series of atmospheric river (AR) events from December to March built an extreme snowpack, topped off reservoirs, and filled natural and engineered waterways that recharge depleted groundwater throughout the state. Much like 2017, this wet year broke a 3-year dry spell that severely stressed water availability. Such erratic weather patterns over the past decade may be forcing water managers to change their practices as surface water supplies become less reliable and groundwater overdraft remains untenable. The winter of 2023 could ultimately be looked back on as the year that managed aquifer recharge (MAR) became an integral part of the water portfolio across the state. For many, seeing water surging through the Delta, flooding the ancestral Tulare Lake area, and overtopping levees, it was clear that more water is available in the wettest years than can be currently stored. In the face of continued extreme wet and dry climate cycles, reducing flood risk and recharging groundwater supplies in wet years is essential to sustainable groundwater management. With several basins in the State continuing to experience groundwater overdraft, the following three strategies remain foundational to sustainable water management: (i) increase supply, especially through
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2023 Summer Issue
alternative sources like treated wastewater and desalination; (ii) decrease demand and promote conservation; and (iii) increase water storage. Given the cost, regulatory challenges, and limited site availability for surface storage projects, the biggest opportunity to increase storage in the State is to utilize subsurface storage through MAR. California’s groundwater basins can hold more than 850 million acre-feet (AF), far exceeding the 50 million AF of storage capacity in existing surface water reservoirs.1 Recent state plans and funding reflect the importance of expanding MAR. Governor Newsom’s 2020 Water Resilience Portfolio and 2022 Water Supply Strategy laid out a master plan for drought resiliency with a focus on MAR. California Department of Water Resources (DWR) funded the Drought Resiliency program in 2021 and 2022 to increase water management and the reliability of water supply. On March 10, 2023, Governor Newsom issued an executive order suspending regulations and restrictions on permitting MAR projects, enabling water agencies to divert flood stage water for the purpose of recharging groundwater. MAR also has significant potential to help achieve ecosystem goals required by numerous existing funding sources, as it can often provide habitat for endangered and threatened species like salmon and migratory birds. While groundwater recharge is a statewide mission, this article highlights three areas that are at the forefront of MAR: Orange County, Sonoma County, and the San Joaquin Valley.
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