Fremont Weir Alternative 5
As part of the DWR/USBR Yolo Bypass Salmonid Habitat Restoration and Fish Passage Project EIS/EIR to identify and evaluate alternatives to address fish passage issues for salmonids and sturgeon and provide habitat for juvenile salmon in the Yolo Bypass, MWD proposed the Multiple Gates alternative (Alternative 5).
cbec furthered the performance evaluation of Alternative 5 leading to a preferred design.
Preliminary hydraulic modeling in HEC-RAS was used to optimize cross sectional geometries for the transport channels and operational schemes for the multiple gates to meet fish passage criteria for the transport channels and intake structures for a broad range of Sacramento River levels.
The HEC-RAS modeling was then used to prepare 10% grading plans that were used to develop quantities for construction cost estimating and quantifying potential impacts to existing habitats.
The hydrodynamic model TUFLOW, developed by cbec and HDR during the EIS/EIR, was then used by cbec to evaluate the ability of Alternative 5 to create floodplain habitat and improve fish passage within the Yolo Bypass relative to the other alternatives while reducing the potential downstream impacts and providing other benefits on the environment (including flood safety, land use, and other environmental considerations).