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A recent tour of California’s Central Valley given by the nonprofit organization Water Education Foundation included a stop at the USGS California Water Science Center’s extensometer near Porterville.

USGS scientist Michelle Sneed explainins the extensometer
USGS scientist Michelle Sneed explaining the extensometer to group from the 2022 Water Education Foundation Central Valley Tour.

Tour participants, made up of water industry professionals, were met by USGS groundwater scientists Michelle Sneed and Justin Brandt who showed the extensometer to the group. The extensometer is one of several that dot the Central Valley. Extensometers measure compaction and expansion of an aquifer system, providing depth-specific data that can help scientists better understand the rate, extent, and at what depths in the system land subsidence is occurring.

Ms. Sneed discussed how land subsidence occurs, and the impacts it has on infrastructure. Land subsidence is the settling or sinking of the Earth’s surface caused by subsurface movement of earth materials. In the San Joaquin Valley, land subsidence is primarily caused by the compaction of the aquifer system from groundwater overdraft.

Communicating information about issues like land subsidence in California is an important part of USGS outreach. The California Water Science Center is pleased to continue its partnership with the Water Education Foundation to help educate the public about water-related issues facing California.

Learn more about this event.