Today, DC Water broke ground on the Piney Branch Tunnel, the final major tunnel in our Clean Rivers Project. This work will help keep sewage and trash out of local waterways and make Rock Creek, the Potomac River, and the Chesapeake Bay cleaner for our community.

When we finish the Piney Branch Tunnel, it will hold at least 4.2 million gallons of rainwater and wastewater during heavy storms. Instead of overflowing into Piney Branch, that water will go to the Blue Plains Water Resource Recovery Facility, where it will be treated.

"We have already seen how the Clean Rivers Project can make a real difference for the Anacostia River, and this project will bring those same benefits to Rock Creek and the Potomac River,” said DC Water Interim Chief Executive Officer and General Manager Matt Brown. “The Piney Branch Tunnel is one more way we are protecting our waterways and building a cleaner, healthier future for everyone who lives, works and enjoys the outdoors in DC.”

The project includes, about a half-mile, 22-foot wide tunnel deep underground, along with other features needed to hold the combined stormwater and wastewater during heavy rain. This summer, our crews will prepare the site before tunneling starts. In the fall, we expect crews to begin digging through rock, which will include planned blasting.

Much of DC’s sewer system is more than 100 years old. During heavy rain, it can take in more water than it can handle. When that happens, rainwater mixed with wastewater is released into creeks and rivers. That adds pollution and trash to our waterways and can harm fish and other wildlife.

Right now, this happens in Piney Branch about 25 times a year. With the tunnel, we expect it to happen about once a year and cut the amount of overflow by 96%.

The Piney Branch Tunnel is scheduled to be finished by the end of 2029. Along with the Potomac River Tunnel, which we are also building now, this project will complete the Clean Rivers Project and help us protect DC’s waterways for years to come.

To learn more, visit our Piney Branch Tunnel project page at dcwater.com/pbt or email us at dcpineybranch@dcwater.com.