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Groundwater Sustainability was the topic of the latest LWVP Climate Series event

Jennifer Trainor | Published on 1/20/2023

Tim Godwin screenshot
On Wednesday, January 18th, the League of Women Voters of Piedmont hosted a Zoom event entitled “Sustainable Groundwater in California: The Challenges Ahead.”  The scheduled speaker, Paul Gosselin, Deputy Director of Sustainable Groundwater for the State Department of Water Resources had a last-minute emergency.  Tim Godwin, Technical Policy Advisor for Sustainable
Groundwater spoke instead.


Mr. Godwin spoke in detail about the requirements and mechanics of the Sustainable Groundwater Act (SGMA), the first California law to regulate groundwater.  SGMA became law in 2014.  In times of drought, groundwater supplies up to 60% of the State’s total water needs.  Even in wetter years, groundwater can account for 40% of total state usage.  There are some basins that are 100% dependent on groundwater.  
SGMA implementation is envisaged over a 20-year horizon.  The Act enables the formation of local Groundwater Sustainability Agencies (GSAs), which oversee basins in their areas.  Of more than 500 alluvial  basins, SGMA has identified 21 that are critically overdrafted. An additional 94, representing 90% of total groundwater pumping in California,  are considered high and medium priority.  Currently, plans for 8 of the 21 critical overdraft basins have been approved.

SGMA defines sustainability in terms of six conditions to be avoided: 1) lowering groundwater levels, 2) reduction of groundwater storage, 3) seawater intrusion, 4) degraded water quality, 5) land subsidence, and 6) depletion of interconnected streams.  As an example of land subsidence, Godwin told of the Friant-Kern Canal, which has had a 60% reduction in its ability to convey water, due to the partial collapse of land subsidence. He noted that when land above an aquifer starts to collapse, it threatens bridges, railways, pipelines and water pipes. 

Godwin explained that determining the appropriate metrics for groundwater pumping, water levels and recharge is a complex process. Each local agency needs to evaluate the level of demand for water, sources of supply, risk of contamination, performance of local wells, and many other factors.

To learn more about this talk and see the presentation, please visit our YouTube channel.


Resources:
  • SGMA portal - View and download information related to groundwater sustainability agencies (GSAs), groundwater sustainability plans (GSPs), alternatives to GSPs, adjudicated areas, and basin boundary modifications. Public comments can also be submitted to the Department.
  • California Groundwater Live - Get the latest groundwater information and conditions including groundwater levels and land subsidence information based on DWR's Interferometric Synthetic Aperture Radar
  • Presentation slides used for this event: Sustainable Groundwater Management Update
  • Do you have questions for the California Department of Water Resources? Please email SGMPS@water.ca.gov





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