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Justin Carl, Caitlin Feehan and Ryan Payne (from left to right) with a portion of Hazel.
With the completion of a two-mile long tunnel along the Alexandria waterfront, the tunnel boring machine (TBM) affectionately known as Hazel brings Alexandria one step closer to clean water.
Grace Kenyon
The shaft at the end of Hazel's journey underground.
At a Mining Completion Open House on Saturday, curious members of the community were invited to the site of the 100-foot drop shaft where Hazel completed her journey and was lifted back to the surface.
Staff members in neon construction vests used diagrams and models to explain how Hazel’s tunnel will soon become part of a system piping sewage overflows from Old Town to the AlexRenew wastewater treatment facility. Kids in blue hardhats stuck their heads in the nooks and crannies of Hazel’s enormous front shield, a segment of the 380-ton machine that was on display. Families climbed onto a platform overlooking the drop shaft, which was so deep you couldn’t see the bottom.
This celebration marked an important milestone in Alexandria’s largest development project, which is scheduled to be finished in 2025. With the completion of the tunnel, the project is about 70% complete, said Justin Carl, general manager and CEO of AlexRenew. Despite setbacks caused by the pandemic and the war in Ukraine (which delayed the shipping of the TBM from Germany), Hazel and her crew completed the tunnel in record time.
Reflecting on the accomplishment of completing the tunnel, Carl says that building tunnels is always risky — as it digs through the Potomac clay, the TBM machine lays segments of the concrete tunnel in a ring behind it.
“So she can’t back up,” Carl said. “Whatever we hit underground, we have to go through.”
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Currently, millions of gallons of overflow sewage and rainwater flow into the Potomac each year. This is because Old Town Alexandria is built on top of a Civil War-era sewage system that collects rainwater and sewage in combined pipes. When it rains, the overflow is diverted into the river. While this system was innovative when it was built, Carl says this project is a much-needed update.
“What's important to us and our team is that we're building a future for the Potomac River and for future generations and doing our part to clean up almost two centuries of pollution,” Carl said.
While this tunnel was completed in record time, it is not the first project of its kind in the area. Both project manager Ryan Payne and Chief Administrative Officer Caitlin Feehan worked on a similar project in Washington DC.
Feehan says that AlexRenew is eager to invite the community into the process in as many ways as possible through education and outreach. Hence the hardhats, children’s books, and neat diagrams.
Payne echoed this, expressing gratitude for the workers who spent 10 hour shifts underground. He hopes the RiverRenew outreach will help the community appreciate the scale of the project and its importance.
“So much of what we do is underground and you just ever see it,” Payne said. “At the end of the project, you'll see a manhole, right? And it doesn't really do justice to the millions of dollars and all the effort and time of the people that are here.”
