WHAT ARE WE DEALING WITH? A SURVEY OF GROUNDWATER SUSTAINABILITY PLANS IN CRITICALLY OVERDRAFTED BASINS
by Kevin W. Bursey*
Since the enactment of the Sustainable Groundwater Management Act ("SGMA") in 2014, the Department of Water Resources ("DWR"), the State Water Resources Control Board, and the myriad of new groundwater agencies across the state have been developing a new paradigm for groundwater management in California.1 Groundwater Sustainability Agencies ("GSAs") overseeing critically overdrafted groundwater basins submitted their adopted Groundwater Sustainability Plans ("GSPs") to DWR for review on January 31, 2020. Nowâfor the first timeâa collective picture is emerging for critically overdrafted basins as GSAs reveal the status of their groundwater conditions.2
SGMA requires that critically overdrafted basins must be managed sustainably by 2040.3 This mandate requires GSAs to estimate the amount of pumping that can be sustained over timeâi.e. a "sustainable yield"; meaning the maximum quantity of water (calculated over a base period representative of long-term conditions in the basin, including any temporary surplus) that can be withdrawn annually from a groundwater supply without causing undesirable results.4 Under SGMA, such "undesirable results" include significant and unreasonable declines in groundwater levels, reduced storage, seawater intrusion, degraded water quality, land subsidence, or depletion of interconnected surface water.5 GSAs must determine how many acre-feet per year ("afy") may be pumped without causing one or more of these undesirable results.