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San Francisco

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SFPUC's Bay Tunnel Reliability Upgrade Project


The San Francisco Public Utilities Commission (SFPUC) conducted a Bay Tunnel Reliability Upgrade project.  The Bay Division Pipeline Reliability Upgrade Project consists of constructing the 21-mile Bay Division Pipeline No. 5 (BDPL No. 5) from Irvington Tunnel Portal in Fremont to Pulgas Tunnel Portal near Redwood City, including a tunnel (Bay Tunnel) under the San Francisco Bay and adjacent marshlands.

AEW was retained by Jacobs Associates (Jacobs) to perform a hazardous materials evaluation on the potential excavation materials along the proposed alignment alternatives for SFPUC.  The primary objective of the investigation was to identify toxic or hazardous materials that could potentially influence construction methods and disposal of to-be excavated materials during the construction of the Bay Tunnel including tunnel and shafts.  AEW worked with Jacob’s geotechnical investigation team to collect soil and groundwater samples for chemical analyses at various intervals from borings over land and in the marine environment to minimize sampling investigation time and cost.  Following the sample collection, the sample chain-of-custody documentation was prepared.  The soil and groundwater samples were submitted to a California-Certified laboratory for chemical analyses.  During drilling, soil core lithologic information was recorded onto field boring logs using the Unified Soil Classification System (USCS). Upon completion of field investigation, AEW prepared a report presenting the results of the hazardous materials investigation.  The report consisted of sampling and chemical analysis protocols, results, conclusions and recommendations on the potential disposal options of soil during construction.