Zinfandel Lane Bridge fish barrier removal, before (left) and after.
56 Miles of Streams Opened for Migration
After standing for over 100 years, the apron for the Zinfandel bridge was losing structural integrity due to significant damage done by erosion. Between six and ten feet had been worn away at the base of the bridge apron, creating a twelve-foot-high step that made fish migration extremely difficult. By 2005, it was clear that this issue needed to be addressed, and so the RCD recieved funding from the US Army Corps of Engineers to create a plan to improve conditions for local fish. Ultimately, it was decided that the bridge apron would be replaced by two channels, which would remain passable over a broad range of flow rates.
Construction was finished in 2011 and resulted in renewed access for steelhead and salmon to over 56 miles of streams, including some of the highest quality streams in the valley. The project also provides a new, solid foundation for the historic bridge, which was slowly being underminded by the erosive force of the river.
- Significance: The Zinfandel Lane Bridge was first built over 100 years ago, but over the years erosion has significantly undermined much of the area around the apron, creating a problematic fish barrier that greatly increased the difficulty of fish migration.
- Where: Zinfandel Lane Bridge, South of St. Helena
- Results: The significantly eroded bridge apron was replaced by two channels, designed to be passable over the broad range of flows that the Napa River experiences in a year. This made over 56 miles of streams, or one third of the total salmonid habitat, available to local chinook salmon populations.
- Funds: The California State Coastal Conservancy, Napa County Measure A, U.S. Army Corps of Engineers, and the Peter A. and Venice H. Gasser Foundation
- Partners: Napa River Steelhead, Sierra Club, Friends of the Napa River, Rutherford Dust Society, Regional Water Quality Control board, California Department of Fish and Game, National Marine Fisheries Services, and the U.S. Fish and Wildlife Service