The $800 million BART Silicon Valley Berryessa Extension (SVBX) Design-Build Project is the 9.9-mile segment from Warm Springs in Fremont to Berryessa in San Jose, which includes the Upper Penitencia Creek Improvements. The project required interfacing with multiple stakeholders in a complex federally funded environment. Relevant work on the SVBX extension included bridge construction, mass grading, culvert installations, a siphon reconstruction, and floodwall installation work along 11 different creeks, through two counties and three cities.
The Upper Penitencia Creek Improvements project is particularly relevant to the SCVWD Watershed projects. Directly relevant project elements include:
- Widening and realigning a 1,000 ft. section of Upper Penitencia Creek from a 45 ft. wide man-made trapezoidal channel (capacity of only 760 cfs) to a 200 ft. wide braided channel with a newly created 1-acre floodplain capable of conveying 4,850 cfs, equal to the 1% flood flow.
- Creation of a meandering, braided channel with riffle and pool morphology, a backwater wetland refugia pool for steelhead, and a stream corridor habitat planted with locally collected native wetland and riparian species to improve the existing degraded condition of the creek
- Replacing a culvert, rip rap, and channel armoring with habitat-friendly features such as two free-span bridges and numerous bio-engineered measures, including 50 large wood structures, a cribwall, bio-engineered outfall structures. and bioengineered bank stabilization
- Driving sheet piles and concrete piles near residences and immediately adjacent to protected steelhead habitat in channel