A Successful Restoration for the Napa River

12.12.2011

The Napa River flows though one of the most scenic landscapes in the Bay Area, and supports one of the largest remaining salmon runs, but it faces many challenges. In the mid 20th century the river corridor was squeezed from a broad ribbon to a narrow thread, as land managers cut off secondary channels and confined the river behind levees. At the same time urbanization and land drainage funneled more water into a narrower floodway. The result was channel incision – unable to spread its energy across a wide floodplain the river cut down into its bed, causing the banks to fail. Bed erosion and disconnection from the former side channels removed spawning and rearing habitat for Chinook salmon and steelhead trout, leaving juvenile fish exposed to fast flows. Bank erosion buried the spawning gravels and caused loss to valuable vineyard land.

For the last eight years ESA PWA has been working with Napa County and local landowners and vineyard managers to develop a restoration plan for the Napa River. The plan involves setting back levees and creating a series of restoration nodes where the river can spread out again into multiple channels and backwater alcoves. This gives juvenile fish a place to take refuge from the mainstem during high flows, and also creates conditions for riffle-pool formation. The video shows two of our restoration nodes following the two year flood. You can see many of the processes we intended to promote starting to occur. Over the next few years we hope to create more of these nodes over 13 miles of the river, and to monitor them so we can adaptively improve the design.

See ESA PWA's Jorgen Blomberg discuss this project on the December 9, 2011news including KTVU.com's RUTHERFORD: Winemakers along Napa River sacrifice land for salmon, ABC 7's Napa Valley growers sacrifice land for new project, and CBS San Francisco's Napa Valley vineyards join effort to restore river.