City of Richmond │ San Pablo Creek Slope Stabilization Project

Richmond, CA

A large landslide about 60 feet in depth formed requiring closure of Via Verdi, the only way in and out of a residential community, with damage to utilities and threatening conveyance of San Pablo Creek waters and releases from the upstream reservoir.

NCE designed in a matter of days a new bypass roadway up around the landslide to allow safe access to residents and routing of utilities. This was then constructed over a weekend with an emergency contractor.

Project Description

A large landslide adjacent to San Pablo Creek in the City of Richmond, CA created public safety and public access issues, increased flood risk, compromised local roadway, and had the potential to continue to damage multiple utilities. To design and construct an emergency access road, NCE quickly got to work completing field investigations, evaluating slide mass characteristics, and monitoring ongoing movement. Once this was complete, NCE undertook a full alternatives analysis, conducted regulatory agency consultations and permitting, drafted environmental documents, completed hydrology and hydraulics studies, and developed the final design to stabilize the landslide by placement of a large toe buttress in the creek channel and a large 26-foot-wide box culvert to convey creek waters. NCE then initiated design of a reconstructed road that would feature stable slopes and drainage and protect nearby homes and utilities.

The final design also included a number of habitat protection and mitigation measures including a meandering streambed and skylights within the culvert for fish passage, bioengineered slopes, revegetation and tree plantings, and green infrastructure drainage swales to treat stormwater. NCE was also responsible for all environmental and regulatory compliance permit management, biological and paleontological monitoring, pre-construction surveys, construction support services, and post construction monitoring.