Napa Dry Bypass Flood Control Project

High Flow Bypass Channel and Creek Restoration Requiring Fish Rescue and Relocation, Biological Consulting, Permitting, and Monitoring during Construction.

24033 napa bypass channel under construction

As part of a comprehensive flood control program for the County of Napa, a high flow bypass channel and creek restoration at the confluence of Napa Creek and Napa River was constructed in downtown Napa.  Project work included excavation of a new bypass channel, sheet pile driving to support bank stability, and woody debris placement for restoration in Napa Creek.  The project was the fifth in a series of major flood control projects designed to increase flood capacity and conveyance in a more natural manner and to protect downtown Napa.

24033 napa bypassWRA conducted breeding bird surveys, provided biological construction and pile driving monitoring, conducted fish rescue and relocation, and assisted with environmental permit compliance.  During sheet pile driving, changes in the bank depths resulted in last minute changes to the work approach and timing.  WRA was able to provide biological information and assist with modifying the project’s California Department of Fish and Wildlife Streambed Alteration Agreement.  Since permit changes required fish species monitoring in the project area of the Napa River, WRA provided otter trawl fish sampling which allowed the project to continue sheet pile driving.  WRA’s rapid response to fish exclusion, salvage, and sampling requirements prevented costly delays and allowed necessary tasks to be completed on time.


  • Construct a bypass channel and creek restoration at the confluence of Napa River and Napa Creek
  • Monitor, relocate, and protect special-status fish and wildlife resources during construction process


  • Fish Rescue and Relocation Plan
  • Fish Salvage and Summary Report
  • Construction and Pile Driving Monitoring
  • Otter Trawl Fish Sampling