In 2005, a small depression in the Front Street alignment next to the San Ramon Creek right of way began to pool water. As the ponding increased, the curb was eventually overtopped, which caused two small segments of steeply sloped creek bank to become supersaturated and fail into the creek. In addition to uprooted trees and other vegetation, the failure also undermined the guardrail, curb and gutter, and a portion of the AC pavement and threatened underground utilities within Front Street. Storm damage in 2005 also impacted a slope located on El Pinto Road which was also supersaturated and caused a landslide/erosion failure that, while similar, was not within a creek bank.
ENGEO was the prime consultant for the project and completed the design, plans and specifications for a soldier pile and lagging wall system supported on tie-back anchors for the repair area as well as creek restoration improvements at the toe of the wall which extended into the active creek channel. The plans and specifications for the project were approved by the San Francisco Bay Regional Water Quality Control Board (RWQCB), the United States Army Corps of Engineers (USACE), the California Department of Fish and Game (CDFG), the United States Fish and Wildlife Service (USFWS) and the Town of Danville.
ENGEO provided a cost estimate and support during the bidding and construction phases of the project including working with the selected contractor to select wall materials and components in conformance with the project specifications, and to select erosion control materials in conformance with USFWS and RWQCB permits secured for the project. We also provided observation of permanent ground anchor installation, rock structure installation and performed compressive strength testing of the concrete pile footings. Construction was substantially complete as of November 2008.