The South Coast Water District owns and operates a 2-mile long gravity-fed 24″ sewer line and the tunnel it runs through—both of which were initially constructed in the 1950s. Due to the structure’s deterioration and lack of support, the owner developed a multi (four) phase approach to rehabilitate the existing tunnel, install new sewer pipe, and reconnect the 80+ lateral services. Drill Tech was awarded all four contract phases, each concerning a unique scope. The project included 10,000 LF of reinforced concrete pipeline encasement, 10,000 LF of concrete invert placement, and 24″ sewer main.
There were several environmental accommodations made throughout this project including limited access through the beach due to the grunion run, Paleontologist inspection for fossils every 1,000′ of tunneling, and vibration and noise monitoring on equipment. Excavation occurred next to the live sewer main, requiring careful operations and gas testing. Drill Tech’s active partnering with the client, regulating authorities, and 3rd party stakeholders enabled the identification of issues in real-time and efficient development of solutions in the field as there were numerous unknowns encountered daily throughout the project.
Contract Value:
$81M
Delivery Method:
Bid-Build
Property Owner:
South Coast Water District
General Contractor:
Drill Tech Drilling & Shoring, Inc.