Chasing Sustainability: Establishing Management Goals and Thresholds

Effective January 1, 2015, the Sustainable Groundwater Management Act (or SGMA) establishes a new structure for sustaining groundwater in California and, for the first time, attempts to locally manage groundwater use. SGMA requires preparation of Groundwater Sustainability Plans (or GSPs) by Groundwater Sustainability Agencies (or GSAS), which include a definition of basin sustainability and a plan to achieve the desired sustainability goal. For the 150+ groundwater basins that are required to comply with SGMA, this will means not only defining sustainability in terms of six distinct sustainability indicators, but determining the thresholds or limits by which the groundwater basins will be managed. SGMA requires the development of minimum thresholds and measurable objectives for each of the six sustainability criteria, but also requires that these thresholds be developed in an open and transparent process considering all the users of groundwater in the basin (including the environment) AND that these thresholds be coordinated between subbasins to ensure that they do not result in adverse impacts outside the subbasin managed by the GSP. For Delta-Mendota Subbasin, with six GSPs, 23 GSAs and eight adjoining subbasins, developing these thresholds is an exercise in both science and coordination on many scales. This presentation will summarize the efforts put forth to develop these sustainability goals and thresholds and how it was achieved in the context of a much larger, regional coordination effort.