Tehama County

Regular Item

Presentation on Groundwater Sustainability Plan Regulations -Bill Ehorn, Department of Water Resources


Department:Groundwater Sustainability Agency Groundwater CommissionSponsors:
Category:Informational Presentation


Informational presentation by the Department of Water Resources (DWR) on the Groundwater Sustainability Plan (GSP) Regulations required by the Sustainable Groundwater Management Act (SGMA) of 2014.


The Sustainable Groundwater Management Act was approved in September of 2014 and became law on January 1, 2015. SGMA legislation directed DWR to develop regulations pertaining to the development of Groundwater Sustainability Plans. DWR finalized the Plan regulations in June of 2016.


Bill Ehorn, Supervising Engineering Geologist for DWR's Northern Region Office will provide information on the GSP regulations with an emphasis on the required contents. Additional information can be found on DWR's Sustainable Groundwater Management Act website

Meeting History

Mar 22, 2017 8:30 AM Audio Groundwater Sustainability Agency Groundwater Commission Regular
draft Draft

Bill Ehorn, Department of Water Resources Supervising Engineering Geologist, presented information on the Groundwater Sustainability Plan regulations required by the Sustainable Groundwater Management Act of 2014.

Clay Parker questioned how much land subsidence has been detected in Tehama County.

Bill Ehorn replied NASA data and the DWR Northern Region survey crews have detected 3 to 4 inches of subsidence in the Hamilton City area of Glenn County Approximately one foot of subsidence detected in the Arbuckle area of Colusa County. Tehama County has not been resurveyed since 2008; the entire Sacramento Valley is currently being resurveyed. It is anticipated a detailed report of the results will be relased in fall 2017.

Executive Director Gary Antone added Department staff was involved in the initial set up of sites in 2008 and are aware of potential area of concerns in Tehama County. To date, we have not had any issues.

Commissioner Bonner asked if subsidence occurs with the rise and fall of local water tables.

Bill Ehorn explained elastic and inelastic land subsidence, noting clay may compress and rebound when rewetted. At some point clays are compressed so much they do not rebound.

Commissioner Grine questioned how underground infrastructure is affected in areas with one foot or more of subsidence.

Bill Ehorn answered it is typical to see well pads rise slightly in areas with subsidence in the one foot range.The Arbuckle area expereinced cracks in bridge abutments, which were reported to Caltrans. Overall, infrastructure issues in the Sacramento Valley have been minimal.

Bill Ehorn noted there has been an increase of land use over the last decade as more orchards have been planted in areas that were previously native pasture, and are using are now using groundwater. Ryan Teubert added that it will be necessary to provide educational outreach and work with ranchers and farmers on groundwater extraction issues.

Supervisor Burt Bundy expressed concerns related to out of County impacts on our groundwater. The State Water Board is determining instream flows that is exporting water out of Tehama County. Supervisor Bundy asked if Tehama County has a say in how those impacts will affect our sustainability.

Bill Ehorn did not have an answer at this time.

Todd Hamer added he appreciates the work by Bill Ehorn and requested additional information on Tehama County specific data, including recharge zones and aquifer descriptions, to see what the County looks like on a groundwater sense.

Bill Ehorn noted he has discussed future presentation topics with staff.

Commissioner Bonner asked if Tehama County has a hydrographer; Ryan Teubert stated not at this time. If the need arises, a consultant could be hired, providing funding is available.

Commissioner Bonner asked if DWR will have charts or graphs for us showing cause and affect of a 25% required water usage cutback. Bill Ehorn replied that is not something DWR typically provides, and that it could be part of the water budget analysis.

Ryan Teubert added that the District’s Groundwater Sustainability Plan will be a base document to build upon.

Commissioner Fleharty asked about the status of Groundwater Sustainability Agencies throughout the state. Bill Ehorn noted many agencies across the state still have overlap issues and are working to resolve any conflicts by July 1, 2017.