SAN FRANCISQUITO CREEK BONDE WEIR
FISH PASSAGE IMPROVEMENT

The Bonde Weir is located just downstream of a Caltrain bridge crossing between the cities of Palo Alto and Menlo Park, California on an incised section of San Francisquito Creek. The weir serves as a grade control structure to prevent streambed degradation beneath the structural supports for the Caltrain bridge and the "El Palo Alto” Redwood tree - California's oldest living historical landmark. Bonde Weir was recognized by the San Francisquito Creek Watershed Council's Steelhead Task Force as a barrier to passage by steelhead trout. At times, upstream-migrating adults as well as out-migrating juvenile steelhead may be delayed or prevented from passing the weir. The San Mateo County Resource Conservation District (SMCRCD), the project sponsor, received a grant from National Fish and Wildlife Foundation's San Francisco Bay Salmonid Habitat Restoration Fund to improve passage at the weir. NHC was contracted by SMCRCD to design a grade control structure to replace Bonde Weir that would meet fish passage needs without adversely affecting stream hydraulics under extreme streamflow events.

NHC initially identified steelhead passage criteria and performed hydrologic analyses to identify fish passage flows. We then used one-dimensional hydraulic models to develop a rock ramp design that provided the same function as the existing weir and also satisfied fish passage criteria. The design was brought from concept plan to final design plans and technical specifications. NHC also helped SMCRCD acquire the needed project permits. The final design includes a 1% grade rock ramp constructed of engineered streambed material and boulder buttresses. The project was constructed on time and within budget in the summer of 2013.

Link to San Jose Mercury News article