RiverRenew Tunnel Project Construction Kicks Off In October

ALEXANDRIA, VA — Ground was broken for the RiverRenew Tunnel Project to remediate four combined sewer outfalls in Alexandria on Thursday, according to AlexRenew, the city's wastewater treatment provider.

The project results from a 2017 law passed by the Virginia General Assembly requiring the four existing combined sewer outfalls to be remediated by July 1, 2025. While most of the city isn't served by combined sewer systems, a portion of Old Town is served by the combined sewer outfalls. These outfalls send sewage to a wastewater treatment facility when the weather is dry, but too much rain in the system can cause a mix of stormwater and sewage to overflow into local waterways.

The $454.4 million RiverRenew project is described as a water quality construction project that could help keep over 120 million gallons of combined sewage out of local waterways each year. While Tunnel Project construction is beginning this fall, AlexRenew has been preparing for construction since acquiring ownership of the combined sewer outfalls from the city in 2018. Construction is expected to continue through July 2025.

"Our team has worked incredibly hard to advance the largest infrastructure project in our city’s history to this point, and the best is yet to come," said AlexRenew general manager Karen Pallansch. "In reaching this major milestone, we’re one step closer to bringing healthier waterways to our community members, wildlife, and future generations."

The Tunnel Project includes a two-mile-long underground tunnel, diversion facilities to direct combined sewage into the tunnel system, a half-mile-long Hooffs Run Interceptor, pumping stations and superstructure to house pumping station equipment. Combined sewage will be treated and cleaned at the AlexRenew wastewater treatment facility before being returned to the Potomac River. AlexRenew believes the project will reduce harmful overflow events from 70 to less than four each year.

The Potomac Riverkeeper Network, an environmental nonprofit, advocated for the Virginia General Assembly setting the 2025 deadline for the remediation.

"That's not just a requirement. It's not a deadline," said Nancy Stoner, president of the Potomac Riverkeeper Network, at the groundbreaking. "This is critical infrastructure for protecting public health and making Potomac swimmable again. That is our goal."

The Potomac Riverkeeper Networker has a water quality monitoring program at 20 or more sites and releases results on the Swim Guide app.

"What we found at Oronoco Bay and other places that have raw sewage discharges going in the water after it rains, the E. coli standards are often violated," said Stoner. "There is a public health threat associated with going in the water for those who kayak, those who do stand-up paddleboarding and fall in, and those who row crew like the high school students here in Alexandria. So it's really important to make this investment."

The groundbreaking ceremony was held at the Pendleton Street outfall, where construction will begin in October. According to Pallansch, the Pendleton Street outfall will be the "end point" for the two-mile tunnel that will receive combined sewage from four outfalls and send it to the treatment facility. The outfall will get a new diversion facility to receive the combined sewage.

November will mark the start of construction at Royal Street, where another diversion facility will be constructed to prevent combined sewage from entering Hunting Creek. Construction on a new pipeline along Hooffs Run will also begin in November to prevent combined sewage pollution in the stream. The work will happen in fenced construction sites.

Funding for RiverRenew largely comes from sewer rate increases, but AlexRenew also received low-interest loans from state and federal programs as well as a $25 million grant allocated by the Virginia General Assembly.

More information about the project can be found at www.riverrenew.com.