Because groundwater is a functionally finite resource, historical overpumping has led to significant depletion of groundwater supplies. In California, the passage of the Sustainable Groundwater Management Act (SGMA) in 2014 mandated that critically overdrafted groundwater basins be brought back into balance by 2040 to avoid the following six undesirable results, including: chronic lowering of groundwater levels, reduction in groundwater storage, degradation of water quality, seawater intrusion, land subsidence, and depletion of interconnected surface waters. This legislation has delegated the responsibility of designing management plans to reach sustainability to local and regional Groundwater Sustainability Agencies (GSAs). 

 

Water managers often seek ways to store surface water for later use. Underground aquifers in California have tremendous storage capacity, at least 17 times the volume of surface water storage in the state, according to estimates by the California Department of Water Resources. Many GSAs plan to implement groundwater recharge in order to take advantage of this capacity to store large volumes of available surface water during wet years for sustainable withdrawal during dry years.

 

However, many groundwater managers throughout the Central Valley lack the information needed to inform strategic siting of groundwater recharge projects in a way that can achieve benefits for communities and ecosystems.