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Los Angeles Interceptor Sewers


In response to the overflowing of the 80-year-old North Outfall Sewer during the 1997-98 El Nino storms, the California Regional Water Quality Control Board mandated a phased upgrading of the sewer system serving central Los Angeles. The plan called for the construction of two new interceptor sewer tunnels that would divert wastewater from the North Outfall, which would then undergo rehabilitation and upgrading to increase its capacity.

The 17 miles of new interceptor tunnels were divided into two projects: the 11-foot-diameter East Central Interceptor Sewer (ECIS) and the 8-foot-diameter Northeast Interceptor Sewer (NEIS).

Successfully completing this urgently needed project to safeguard public health took the skills and expertise of many. WSP USA—in joint venture—provided design and construction management for the ECIS under a tight 4-year deadline. The sewer received flows on August 9, 2004, ahead of schedule and under budget. ECIS received the 2004 Project of the Year Award from the Southern California Section of the American Public Works Association.