Palomares Creek Restoration
Castro Valley, CA
Alameda County Public Works Agency
Palomares Creek is located in a semi rural area east of Castro Valley, CA. The creek banks at the project site were severely eroded by high stream velocities due to channel entrenchment and surrounding land use. The Natural Resource Conservation Service (NRCS) designed and inspected the project through a partnership with the ACPWA. The design involved repairing two sections of channel with a variety of techniques, including a vegetated log crib wall, rock toe protection with root wads and live staking, and a large, upper bank vegetated soil lift structure.
Extensive clearing of brush and debris was required to prepare the site for excavation. Logs removed during this clearing, as well as eucalyptus harvested off-site, were used for the log structures.
The 80 foot-long log crib wall required excavation in very tight conditions and work on a steep slope. A key trench was excavated, and the crib wall was installed with rock and soil backfill. The wall was constructed with willow cuttings incorporated in the upper layers. Following completion of the wall, the slope was rebuilt above.
Upstream from the crib wall, 350 feet of rock toe protection was installed, which included a 40-foot section incorporating five root wads, and a 25-foot long by 12-foot tall vegetated geogrid. The root wads were anchored using cable and duckbill anchors. The vegetated geogrid was unique, in that it was constructed to fill and stabilize the upper bank, above six feet of rock toe protection. In addition, the structure is primarily in the shade. For these reasons, the first (lowest) lift was planted with willows and the remaining lifts were planted with native blackberries.