A new 380-ton tunnel boring machine (TBM) measuring 14 feet 8 inches tall has arrived at a wastewater project in Alexandria, Virginia.
Dubbed “Hazel,” the TBM marks a significant milestone in the RiverRenew program, managed by Alexandria Renew Enterprises (AlexRenew), to improve local waterways, according to the group.
The TBM came from Schwanau, Germany, according to the authority, .
“Today is a monumental day for Alexandria and our waterways,” said Karen Pallansch, AlexRenew general manager, in a prepared statement. “It’s a huge step forward in our commitment to deliver healthier waterways by 2025.”
Typically, a TBM is named prior to launch per 14th-century mining traditions, according to AlexRenew. TBMs have historically carried a feminine name, as underground workers looked to Saint Barbara for protection. Keeping with this long-standing custom, AlexRenew nominated the names of six women whose outstanding contributions to Alexandria, the environment, or the engineering and construction fields, have paved the way for countless others.
As voted by Alexandrians via an online poll, the TBM was unveiled at the ceremony as “Hazel,” in recognition of Hazel Johnson, one of America’s leading women pioneers for environmental justice who dedicated her life to fixing ecological issues.
The arrival and dedication of the TBM is a major milestone for RiverRenew, the largest infrastructure project in Alexandria’s history, and a critical part of meeting a state-mandated deadline to remediate combined sewer overflows by July 1, 2025. Once lowered more than 100 feet below ground, Hazel will build the new two-mile Waterfront Tunnel with little service interruption on a journey estimated to take just over a year to complete.
After completion, the RiverRenew tunnel system will prevent over 120 million gallons of combined sewage from polluting the Potomac River, Hunting Creek, and Hooffs Run each year, according to AlexRenew.
Leading environmental engineering and construction services firm Brown and Caldwell serves as the Owner’s Advisor on the RiverRenew program.
“It really is a generational project—for us as engineers and planners—but also for Alexandria and future generations who will benefit from healthier waterways,” said Justin Carl, Brown and Caldwell project manager, in a statement.
