Bair Island, Redwood City, California
Working as a subconsultant, CE&G completed a geotechnical exploration for a proposed new 48-inch forced sewer main near Bair Island Slough in Redwood City, California. The new line is to be constructed by microtunneling in old bay mud deposits with several deep launching and receiving shafts. Duties for the project included historical research of the project area, collection of previous exploration data, coordination with local and state permitting agencies, coordination with multiple consulting and development agencies, coordination with the drilling subcontractors, field investigation, laboratory testing selection, and report development. The field investigation included four over-water exploratory borings utilizing a barge mounted drilling rig. The barge drilling rig was launched in coordination with the state and local agencies and private resident of the area and transported several miles along the San Francisco Bay creeks and waterways to the exploration location. The drilling operation lasted four days. The exploration required constant adjustment for tidal influences to maintain the near continuous sampling interval required for up to 92.5 feet below the sediment floor of the San Francisco Bay margin soils.