“Best Management Practices” Will Help Local Water Managers Combat Sinking Lands & Protect Critical Water Infrastructure
July 27, 2025 - SACRAMENTO, Calif. – For almost a century, parts of California have been gradually sinking, impacting critical infrastructure and the communities who rely on it. Recognizing this challenge, the Department of Water Resources has released a draft Best Management Practices document for public comment that will help local water agencies address this growing concern and support groundwater reliant communities.
Known as subsidence, this reaction is caused by various factors including excessive groundwater pumping, which causes the empty spaces between soil particles to collapse and compact the earth. Subsidence poses significant challenges to not only our communities but our state as whole. It damages homes, roads, bridges, levees, wells, and irrigation canals, disrupting water delivery and costing billions in repairs. It is critical that regions experiencing subsidence take action to slow or stop the sinking or be left with the risk of further permanent damage.
Once finalized following public review, the document will serve as a guide for groundwater managers on the basics of subsidence, how to best manage it, and available technical assistance. This document does not replace any existing, local, state, or federal regulations, but serves as a resource that local agencies can add to their water management toolkit.
“Subsidence has significantly impacted our major water conveyance facilities, levees, roads and other land uses affecting water supply reliability and public safety,” said Paul Gosselin, DWR Deputy Director of Sustainable Water Management. “Understanding that conditions and solutions vary by region, it's critical to hear from our local partners and the public on this draft document to ensure that subsidence is minimized effectively.”
DWR Accepting Public Comments
DWR is accepting public comments on the draft Best Management Practices document until September 22. Interested parties are strongly encouraged to submit comments and attend upcoming in-person meetings held in Delano on September 9th, Clovis on September 10th, and Willows on September 11th. These meetings will include an overview of the draft document and serve as a venue to ask questions and provide public comments. More information can be found on DWR’s Public Notice webpage.
Comments can also be submitted by one of the following methods:
Electronic Mail
Letters should be sent to sgmps@water.ca.gov. Electronic files should be PDF or Microsoft Word compatible.
Hard Copy via U.S. Mail
Letters should be addressed to:
Department of Water Resources
Sustainable Groundwater Management Office
ATTN: Subsidence BMP
P.O. Box 942836
Sacramento, CA 94236-0001
Additional Subsidence Support
Today’s efforts help meet objectives set by the Sustainable Groundwater Management Act (SGMA) to avoid or minimize current and future impacts of subsidence. In addition to identifying best management practices, DWR is investing in other methods to further describe and inform subsidence impacts. Projects include the California Aqueduct Subsidence Program, which is designed to address damages to water delivery systems caused by active and anticipated subsidence. The program has allocated $288 million for the California Aqueduct, $582 million for the San Luis Canal, $924 million for the Friant-Kern Canal, and $561 million for the Delta-Mendota Canal.
The support doesn’t stop there. In 2023, California funded $17 million to raise the Corcoran levee, a critical piece of flood protection infrastructure in the Tulare Lake Basin. This is the third time that either the State or federal government intervened to raise the levee due to sinking caused by years of overpumping groundwater. DWR is also installing several subsidence monitoring stations throughout the state to track sinking in the San Joaquin Valley and areas of Northern California. Installation is currently underway, and data collected from the stations will help State and local partners have a better understanding of affected areas.
Understanding that each region is different in their water challenges and needs, changes to groundwater management practices will be site-specific and dependent on existing subsidence conditions and impacts. Regardless of a groundwater basin’s current conditions, the new best management practice document, along with DWR’s assistance team and Region Office staff, will help water managers through their decision-making process to better manage groundwater conditions to avoid or minimize subsidence and achieve their sustainability goals.
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