Napa River Watershed Flood Protection and Habitat Enhancement

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The Napa River Flood Protection Project (NRFPP) is designed to provide 100-year flood protection for the City of Napa combined with restoration of historic tidal marshlands and alluvial floodplains. This strategy, termed the "Living River Strategy" by the Napa Community Coalition, is considered a national model for flood protection and river restoration by the Corps of Engineers.

For nearly 20 years, ESA has been extensively involved in the development of the NRFPP. From organizing and managing technical studies to supporting a complex community planning process, ESA has worked closely with the Sacramento District Corps of Engineers, Napa County Flood Control District, Napa County Resource Conservation District, and the State Coastal Conservancy. Our team designed a multi-stage channel and raised-bed bypass through a highly developed part of Napa; modeled the sediment transport processes through the project reach; and prepared a conceptual enhancement plan for the restoration of more than 1,000 acres of tidal wetlands, alluvial floodplains, and upland areas in the Upper Napa River Estuary. ESA used the MIKE 11 hydrodynamic simulation results and the ArcView extension MIKE 11 GIS to develop Digital Elevation Models (DEMs) and Flood Inundation Maps (FIMs). The maps present differences in flooding extent and depth for pre- and post-project conditions in a format that can be easily understood by a non-technical audience.

ESA provided conceptual designs for flood reduction and restoration of more than 1,000 acres of tidal wetlands, freshwater wetlands, alluvial floodplains, and upland areas on the Napa River. The conceptual designs produced were adopted by the USACE for full design and implementation.

Specialized Services

  • Floodplain mapping
  • Hydrologic and hydraulic modeling
  • Monitoring
  • Multi-objective flood management