Phil Isenberg, Chair of the Delta Stewardship Council, issued the following statement regarding the release of the USGS’s latest report showing extensive groundwater pumping from San Joaquin Valley aquifers is increasing the rate of land subsidence, or sinking, potentially causing serious damage to water delivery infrastructure:
“This report reinforces the urgency of understanding and better managing California’s groundwater basins. The amount and widespread nature of the subsidence found by the USGS is truly alarming and shows that cutbacks in surface water deliveries because of drought or environmental concerns cannot sustainably be replaced or exceeded by continual groundwater extractions.
The report also underscores the urgency of actions and recommendations included in the draft California Water Action Plan (http://resources.ca.gov/docs/Final_Water_Action_Plan.pdf) and the Delta Stewardship Council’s recently adopted Delta Plan (http://deltacouncil.ca.gov/delta-plan-0).
The dramatically dropping groundwater levels and increasing land subsidence found by the USGS in a large portion of the San Joaquin Valley illustrate the problem; fixing it requires understanding the limitations of individual groundwater basins and willingness to manage groundwater pumping sustainably. Historically the state has treated groundwater management as a local issue; however, the USGS report shows that those local jurisdictions must do a better job quickly.
The Delta Plan recommends updating the state’s groundwater plan next year (by Dec. 31, 2014) to determine sustainable yield and overdraft conditions. In the same timeframe, water suppliers that receive water from the Delta should develop and implement sustainable groundwater management plans.
The Delta Plan further recommends that if local or regional agencies fail to develop and implement these plans, the State Water Resources Control Board should take action to determine if the continued overuse of a groundwater basin constitutes a violation of the State’s Constitution Article X, Section 2, prohibition on unreasonable use of water and whether a groundwater adjudication is necessary to prevent the destruction of or irreparable injury to the quality of the groundwater, consistent with Water Code sections 2100 and 2101.”