The Charleston Water System (CWS) is marking a significant milestone with the groundbreaking of the final phase of the West Ashley Sewer Tunnel project. This critical infrastructure effort will help address sewage overflows in rural areas and connect sewage pipes to the Plum Island Wastewater Treatment Plant. The project has been ongoing since 1999 and will ultimately span four miles across West Ashley, linking the towns of Hollywood, Ravenel, and Meggett.
The West Ashley Sewer Tunnel Project
The West Ashley Sewer Tunnel project began more than two decades ago with the goal of replacing outdated tunnels built in the 1960s. The current phase, Phase 5, focuses on creating a tunnel that is 130 feet below the surface and around eight feet wide. Once completed, it will help eliminate sewage overflows that often occur during heavy rainstorms or hurricanes, a persistent issue in West Ashley.
Mike Saia, the public information administrator for CWS, explains the need for the project: “When we have a heavy rain event, maybe four inches of rain or more, we do have some overflows in West Ashley, and if we have a hurricane, we can have many overflows because the pipes simply don’t have enough room to carry the water.” The new tunnel is designed to handle substantial amounts of water, ensuring the area is protected against severe weather conditions.
Environmental Benefits
In addition to improving the sewage system, the project also includes an environmental benefit. The dirt and clay displaced during the digging of the tunnel will be used to fill in strip-mined areas, enhancing the local environment. Saia notes, “The environment is going to win two ways. It’s going to win from a reduction of overflows, and we’re going to fill in some pits that other entities have dug.”
A Record-Breaking Investment
At a cost of $133 million, this project is the largest infrastructure initiative in CWS history. Part of the funding, $10 million, was awarded through the South Carolina Infrastructure Improvement Program. Officials say the investment will significantly improve the area’s sewage infrastructure and help manage stormwater in the long term.
Miss Harper: The Machine That Will Do the Work
During the groundbreaking ceremony, officials introduced the machine that will carry out the heavy lifting of the tunnel project—Miss Harper, a specialized boring machine. The construction team will lower Miss Harper 130 feet down into a pre-dug shaft, where she will begin the process of digging the tunnel. Miss Harper is expected to tunnel 80 to 100 feet per day, and the project is expected to take two to three years to complete.
Stephen O’Connell, a project manager with Black and Veatch, expressed his pride in the project, saying, “This is the work that we love to do, and to see a project going from design all the way to the point where we’re about to put a machine in the ground, it’s a proud moment.” O’Connell noted that working underground will be a challenge for the crew, with cramped spaces and hot conditions, but they are committed to completing the project successfully.
Completion Date
The West Ashley Sewer Tunnel project is expected to be completed by the fourth quarter of 2027. Once finished, it will significantly improve the wastewater infrastructure in the area, helping to prevent future overflows and providing more capacity for managing stormwater.
