Cosumnes River Provides Model for Floodplain Restoration in California
Apr 19, 2017 at 7:00pm
Michelaina Johnson, Water Deeply
Research in the Cosumnes River watershed in the eastern Sacramento-San Joaquin Delta region has shown the benefits to water storage and wildlife from floodplain restoration that could prove useful across the state.
WITH CALIFORNIA’S SURFACE drought over, the state can prioritize investing in groundwater recharge and floodplain restoration to help fight one of its biggest lingering problems: groundwater overdraft. As it does so, the relatively unknown Cosumnes River watershed has emerged as a model.
Roughly half of the groundwater basins in California’s Central Valley are critically overdrafted, including the San Joaquin Valley basin to the south of the Cosumnes. Though groundwater levels in the Cosumnes basin have also appreciably declined since the 1950s, cutting edge research at the Cosumnes River Preserve, a 50,000-plus acre public-private partnership in the eastern Sacramento-San Joaquin Delta, has shown that floodplain restoration can substantially recharge groundwater as well as provide habitat and improve fish migration.
Preliminary results from an ongoing University of California Water study on the Cosumnes River suggests that breaching levees to allow small- and medium-sized floods to inundate agricultural fields could triple the recharge provided by irrigation. This is welcome news as California figures out how to make the state’s surface and groundwater systems more sustainable and have more multi-beneficial uses for humans and wildlife.