Groundwater Sustainability in the Yucaipa Subbasin
The SGMA defines sustainable groundwater management as the “management and use of groundwater in a manner that can be maintained during the planning and implementation horizon without causing undesirable results” (California Water Code, Section 10721). Undesirable results, as defined in the SGMA, are any of the following effects caused by groundwater conditions occurring throughout the basin:
Chronic lowering of groundwater levels indicating a significant and unreasonable depletion of supply if continued over the planning and implementation horizon
Significant and unreasonable reduction of groundwater storage
Significant and unreasonable degradation of water quality, including the migration of contaminant plumes that impair water supplies
Significant and unreasonable seawater intrusion
Significant and unreasonable land subsidence that substantially interferes with surface land uses
Depletions of interconnected surface water that have significant and unreasonable adverse impacts on beneficial uses of the surface water
Maintaining sufficient groundwater in storage to allow for ongoing groundwater production that meets the operational demands of the water purveyors and private well users, and the regulatory commitments established in the Yucaipa GSP Plan Area.
Ensuring that groundwater production does not result in significant and unreasonable loss of groundwater-dependent ecosystems.
Of the six sustainability indicators outlined by the SGMA, four apply to the Yucaipa Subbasin:
(1) chronic lowering of groundwater levels
(2) significant and unreasonable reduction of groundwater storage
(3) significant and unreasonable land subsidence
(4) depletions of interconnected surface water
Sustainability criteria were established in the Yucaipa GSP for each of these four sustainability indicators to evaluate when management actions would need to be implemented to prevent undesirable conditions in the Yucaipa Subbasin.