Parsons and Jacobs Associates has been selected by the Sanitation Districts of Los Angeles County to prepare a feasibility study and perform preliminary engineering for a new tunnel and ocean outfall, where chemically treated wastewater would be discharged into the ocean. The tunnel would start at a water pollution control plant in Carson with an onshore shaft and tunnel and run about 9.65 km until it goes offshore. Offshore it will involve either a tunnel, combination conventional outfall and tunnel or a conventional outfall. The new tunnel and outfall, which would be one of the world's largest and would provide improved reliability and operational capability, would be about 6 m in diameter, and it could be 25.7 to 27.4 km long by the time it is all done. The existing tunnels go about 3.2 km offshore to a depth of 60 m. Those tunnels, 2.4 m and 3.6 m in diameter respectively, are more than 50 years old, and during severe storms they run at full capacity.The districts are evaluating the feasibility of a new tunnel and ocean outfall in the context of a comprehensive master facilities plan to cover its joint outfall system, which serves a large portion of metropolitan Los Angeles County. During the feasibility phase, a team of Parsons and Districts engineers will evaluate several onshore and offshore alignments and potential diffuser locations. Following selection of the preferred alternative, Parsons will perform the preliminary design. Visit www.parsons.com, www.jacobssf.com and www.lacsd.org 36/06.