ENGEO was the lead consultant for the realignment of 250 linear feet of San Ramon Creek at the El Capitan Bridge alignment located in Danville. Due to several dredging interventions upstream, the creek low-flow channel had migrated laterally into the existing bridge abutment and was threatening the integrity of the structure. The Town of Danville secured funding through the Caltrans Local Assistance Program and the Federal Highway Administration to restore the creek in the vicinity of the bridge and provide scour protection at the bridge abutments.
As part of the preliminary engineering phase, ENGEO coordinated the biological, archeological, and hydraulic assessments required by Caltrans. Preliminary recommendations included providing low-flow channel dimensions for the re-graded creek, toe scour protection with biotechnical stabilization at creek bendways, and the installation of an active floodplain with riparian planting to fulfill the wetlands mitigation requirement for the project required by the United States Army Corps of Engineers. The preliminary studies were approved by the Caltrans Local Assistance Program as part of National Environmental Policy Act (NEPA) requirements.
In the final engineering stage, ENGEO completed hydraulic studies, improvement and revegetation plans, specifications and an engineer’s cost estimate for the project which were approved by the Town of Danville, the Contra Costa County Flood Control District, the San Francisco Bay Regional Water Quality Control Board (RWQCB), the United States Army Corps of Engineers (USACE) and the United States Fish and Wildlife Service. During the bidding phase, ENGEO worked with the Town of Danville to answer contractor questions and to clarify the intent of the construction documents. We also provided limited testing and observing during construction of the rock structure installations and compaction testing. We furnished a final testing and observation report to Caltrans after work ended. Construction was substantially complete as of November 2008.
The project was monitored for five years, to demonstrate the repair’s long-term stability as required by the RWQCB and USACE and received final sign-off in 2013.
