Presentations 2016

Managing the Groundwater-Surface Water Interface under California’s new GroundwaterLaw

University of California, Davis

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The California 2014 Sustainable Groundwater Management Act (SGMA), for the first time in the state's history, protects beneficial uses of surface water from significant and undesirable impacts due to groundwater pumping. The law also explicitly protects groundwater dependent ecosystems. Under SGMA, local groundwater sustainability agencies (GSAs) must define monitoring networks, minimum thresholds, and measurable objectives to sustain the groundwater-surface water connection and groundwater-dependent ecosystems. Regulations spell out some minimum monitoring requirements, but provide flexibility in how to plan and implement sustainable groundwater-surface water connections. Among the groundwater sustainability objectives prescribed by SGMA, achieving sustainable groundwater-surface water and groundwater-dependent ecosystem objectives may be among the most challenging: California groundwater basins with some of the least prior groundwater management activities are most affected; the dynamics of the interface may cause long and hidden delays in impacts; and management of groundwater-surface water connectivity is uncommon, hence there are no ready-made toolboxes to look for. Instruments available to GSAs to assess groundwater-surface water connections and the potential impact from groundwater use and management activities can be broadly categorized into: water level data, water budget information, streamflow data, analytical modeling tools, numerical modeling tools, and statistical tools.