Charleston Water System awards sewer tunnel contract

Staff Report
Published Feb. 6, 2013

The final phase of construction for Charleston Water System’s deep tunnel system for raw sewage can begin now that the utility awarded a $50.8 million contract for the construction.

The West Ashley Tunnel will span1.6 miles and be located 120 feet below ground. It will run from Albemarle Road under the Wappoo Cut to the Plum Island Wastewater Treatment Plant off Harborview Road.

Charleston Water System awarded the contract to Southland Renda JV, a joint venture between Southland Contracting and Oscar Renda Contracting. Both companies are based in Texas.

The tunnel project also includes building a new pump station and piping at the treatment plant as well as sewer system improvements in other areas. Construction will take about 30 months to complete, according to a news release.

This new tunnel will replace an existing tunnel, which carries wastewater from West Ashley, parts of Johns Island and the towns of Hollywood, Ravenel and Meggett. The existing tunnel, which was built in the 1960s, is deteriorated and too small for peak wastewater flows. It currently moves about 10 million gallons per day to the treatment plant.

“Sewer infrastructure is something most of us never think about, but it’s absolutely essential to public health, environmental protection, and ultimately our quality of life,” said Kin Hill, Charleston Water System CEO. “Completing this project will make sure we can continue to provide these essential services.”

Replacing the tunnel system has been one of the largest infrastructure projects in Charleston Water System’s history. So far, three sections of tunnel have been replaced at a cost of $135 million. The three sections already replaced include a section on the east side of the peninsula, one on the west side of the peninsula and a third under the harbor. A fourth section was added to collect wastewater from Daniel Island.

West Ashley’s tunnel is that last original section to be replaced. This phase will bring the total cost for the project to $186 million. West Ashley’s section is funded by a 2010 bond issue and supported by current sewer rates, a release said.

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