Floodplains can provide salmonids with particularly valuable habitat, especially for juvenile rearing. The flat valleys where these habitats typically exist are the same areas favored by humans for agriculture and development. Rivers are often confined to single-thread channels as a result of levees, other human-built infrastructure, and legacy mining impacts. Floodplain restoration seeks to improve the area, frequency, and duration of inundation, providing fish with room to access complex and high-quality floodplain habitats. Restoration approaches include managing flows, removing levees, altering sediment deposition, and excavation to reduce floodplain elevation and build habitat features. This session will explore a range of floodplain restoration topics, including: 1) groundwater surface-water interactions in restored floodplains, 2) geomorphic changes, 3) biological responses including vegetation, macroinvertebrate production, juvenile salmonid growth and predation, and adult fish migration, 4) lessons learned, and 5) project design and implementation. The session’s geographic focus is California’s Central Valley, but an Oregon creek is also included.

 

Wiggle, Elevate, Connect: Partitioning the Effects of Increased Aquifer Size, Channel Realignment, and Floodplain Reconnection on Streambed Exchange in a Large Scale Channel Restoration, Byron Amerson, MS, Environmental Science Associates

 

Challenges and Lessons Learned Designing Floodplain Rearing Habitat on Central Valley Rivers, Paul Frank, P.E., CED, FlowWest