SACRAMENTO, Calif. – The California Department of Water Resources (DWR) is using an innovative, helicopter-based technology to gather information about the state’s groundwater aquifer structure to support drought response and the implementation of the Sustainable Groundwater Management Act (SGMA).

DWR’s use of airborne electromagnetic (AEM) surveys advances Governor Newsom’s Water Resilience Portfolio goal of using technology to support the State’s understanding of groundwater resources.

“The data collected during these surveys will provide a better understanding of California’s groundwater systems, and in turn support more informed and sustainable groundwater management and drought preparedness and response approaches,” said Steven Springhorn, DWR’s SGMA Technical Assistance Manager.

Beginning April 24, 2022, DWR will conduct AEM surveys of groundwater basins in Colusa, Butte, Glenn, Tehama, Shasta, Humbolt, Sierra, and Plumas counties, specifically in Colusa, Butte, Wyandotte Creek, Vina, Los Molinos, Corning, Red Bluff, Antelope, Bowman, Bend, Millville, South Battle Creek, Anderson, Enterprise, Eel River Valley, and Sierra Valley groundwater basins.

AEM surveys will be conducted over the next several years in high- and medium-priority groundwater basins around the state, where data collection is feasible. The survey schedule can be accessed from DWR’s AEM webpage or directly from the following link: 

During the surveys, a low-flying helicopter tows a large hoop with scientific equipment approximately 100 feet above the ground surface. The helicopter, flown by experienced and licensed pilots, will make several passes over the survey areas and may be visible to residents.

Survey data creates an image of the subsurface down to a depth of about 1,000 feet below ground surface and provides information about large-scale aquifer structures and geology. This information supports the implementation of local groundwater sustainability plans (GSPs), which can help local agencies sustainably manage groundwater during drought. For more information, please watch DWR’s short 2-minute video on the introduction to the AEM method, provided in both English and Spanish.

YouTube video

The AEM method is safe, and surveys have been conducted successfully in several locations throughout California. Surveys will be conducted during daylight hours only, and the helicopter will not fly over businesses, homes, other inhabitable structures, or confined animal feeding operations. The helicopter operator follows all established Federal Aviation Administration rules and regulations and their highest priority is public safety. Experienced pilots, who are specially trained for the low-level flying required for geophysical surveys, will operate the helicopter.

DWR encourages residents to get involved in their local groundwater management activities and GSP implementation through your groundwater sustainability agency (GSA). Information about local GSAs can be found on the SGMA portal.

For more information about the AEM surveys, visit DWR’s AEM project website. For questions, please email