Historic Floodplain Restoration Reconnects San Joaquin River to 220 Acres in Central Valley

After more than 15 years of planning and construction, the Grasslands Floodplain Restoration Project restored the San Joaquin River’s natural overflow across Great Valley Grasslands State Park, reconnecting over 220 acres of historic floodplain. The work involved breaching levees originally built in the 1950s to contain cattle on a ranch donated by cheesemaker Joseph Gallo in 1982. A June 11 ceremony marked the achievement, with scientists, tribal leaders, state officials and community members witnessing the new river channel.

The restored floodplain is expected to slow water flow, recharge groundwater, curb invasive plants, and provide critical habitat for native wildlife and endangered fish like Chinook salmon. Ongoing monitoring will track water temperature, groundwater levels, zooplankton and vegetation to gauge ecological benefits. The project also paves the way for further floodplain restorations and new park developments in California’s Central Valley.