Contra Costa Supervisor John Gioia and the Contra Costa County Public Works Department celebrated the completion of the new bridge on Alhambra Valley Road with a ribbon cutting ceremony on November 15th. During WY17 storms the old culvert was blown-out and the roadway completely collapsed.
Contra Costa County Public Works Department reached out to Balance for geomorphic and hydraulic engineering design support for the Alhambra Valley Road Crossing Repair in Contra Costa County. The wash-out of the crossing at Pinole Creek had major impacts to all users of this important road corridor. Balance assisted the County with a rapid geomorphic assessment, hydraulic modeling, and fish passage evaluation to put into place a replacement structure. Balance leveraged our extensive experience in the Pinole Creek watershed, including several nearby studies allowing a prompt assessment and recommendations in an expedited manner.
Our technical approach focused on geomorphic and hydraulic assessments with the goal of identifying the dimensions and configurations of a replacement crossing that maximized the functions and values of the creek corridor at the site. The crossing replacement design was carried out under an emergency authorization, however, securing regulatory agency support for the replacement structure was still an important component of the work. To this end, we worked closely with County and agency staff to balance the objectives of both parties in a way that acknowledged cost constraints while providing the desired flood conveyance and fish passage qualities. Pinole Creek is an important creek to Central Coast Steelhead, it is one of the only Bay Area creeks without drop structures, concrete lining, and other fish barriers, it offers miles of fish habitat.
Balance Staff were recognized at the Ribbon Cutting. Great job Barry, Ed, Jonathan, Peter, Montana, and Dana!