South Bay Ocean Outfall - San Diego, Calif.
General Constructions work started almost 2 miles offshore where an outfall tunnel is connected to the seabed by a 9 ft. diameter riser structure. The 10 ft. diameter seabed outfall trunk line originates at the riser and proceeds west for 4,500 ft., to a 320-ton wye structure. From the wye structure, two diffuser lines extend 2,000 ft. to the north and south along the seabed. This project required dredging 210,000 cubic yards of excavation, and placement of 350,000 tons of rock to bed, ballast and armor the 1.6 miles of outfall pipe. All work was performed 2 to 4 miles offshore, and at an average depth of 100 ft. To meet the rigorous schedule of this project, the 500-ton capacity derrick barge D.B. General was utilized. The project required extensive use of divers and ROVs for both installation and inspection purposes. To increase productivity and insure high quality, the latest in GPS and sonar technologies were employed.