Fish passage improvements for Chinook salmon migrating through the Sutter Bypass were made as part of the reconstruction of the old 1920s Willow Slough Weir and replace its culverts to improve water flow for agricultural diversions. The original fish ladder failed to provide the appropriate attraction flow when compared to the water being discharged through the culverts during much of the migration season. The California Department of Water Resources project included the removal of the existing fish ladder and culverts and the replacement of the original culverts with new structures whose design and configuration provide better flow control from the East Borrow Canal into Willow Slough, and provide effective fish passage between the two waterways. A new pool and chute fish ladder, which operates in a greater range of flows (6 to 270 cfs), was constructed through the weir. © CDWR