SFPUC East/West Transmission Main

Project Location

San Francisco, California

Owner

San Francisco Public Utilities Commission

Project Dates

2010

Services Provided

Construction Process Auditing

PROJECT DESCRIPTION

The SFPUC installed approximately 4.5 miles of 36 and 42-inch pipeline from the Alemany Pump Station in the eastern part of the city to Junipero Serra Boulevard at Holloway. Emergency water supplies cannot be pumped from the eastern part of the city to the west. This new transmission line enabled the SFPUC to move water from the east side of the city into the Sunset system in the event of a peninsula pipeline failure or other emergencies. Construction began in February 2007 and has completed in July 2009. This project is one of the water system improvement projects to repair, replace, and seismically upgrade the Hetch Hetchy water system. The project includes Jack and Bore under highway I-280 and BART. Close inspection of the tunnel work would be undertaken to make sure that the ground is responding to the tunnel excavation as anticipated. There were some assumptions and uncertainties associated with the inputs used in the settlement analyses. In order to prevent the potential impact of the tunnel excavation on the BART operations, settlement monitoring during the tunnel excavation would be recommended.