City’s combined sewer system to receive facelift

City’s combined sewer system to receive facelift

By Chris Teale (File photo)

City council approved a new tunnel for a section of the city’s combined sewer system at Hoofs Run and ordered further study of a 3-million gallon storage tank under Royal Street at its public hearing May 14. Councilors also directed staff to speed up the process to mitigate discharge from Pendleton Street into the Potomac River and the city waterfront.

The approvals were part of council’s adoption of an update to the long-term control plan for the city’s combined sewer system, and are designed to prevent an overflow of water, especially stormwater after sustained rainfall.

Combined sewer systems have one pipe that sends sewage and stormwater to a treatment facility. Alexandria’s sewers consist of a patchwork of pipes — some combined and some separate — that cover 15.4 square miles and send sewage and stormwater to different places. Some of Alexandria’s pipes date back to the 19th century.

The long-term control plan was first adopted in 1999, but required an update after VDEQ issued a total mass daily load capping the amount of bacteria that is allowed to flow into Hunting Creek. Bill Skrabak, deputy director for infrastructure and environment in the city department of transportation and environmental services, explained at the hearing that a TMDL is a budget for how much pollution can be dis- charged into a water supply.

The Hunting Creek TMDL applies to discharge locations on Royal Street, Duke Street and at Hoofs Run, while there is a fourth at Pendleton Street in the Potomac River that is not directly affected, since it does not discharge into Hunting Creek.

In 2013, the city was issued a new combined sewer system discharge permit by VDEQ. It stipulates the long-term control plan must be updated to address the Hunting Creek TMDL to reduce the amount of discharge of bacteria into that stretch of water by be- tween 80 and 99 percent. The plan must be implemented by 2035.

City staff’s primary strategy is to store and treat the discharge using a tunnel that is 10 feet in diameter for Hoofs Run and a 3-million gallon tank under Royal Street. In addition, a report suggests implementing a citywide green strategy that would increase the tree canopy among other improvements, all of which would help mitigate stormwater runoff as well.

Staff estimated the plan will cost between $125 and $188 million from the city’s capital improvement budget. To help pay for that, Skrabak said there was the potential for public-private partnerships, but that water bills likely will rise by $10 to $15 a month over the course of 20 years.

“What the phasing does is it allows that increase to go steadily over time, so that there’s not an abrupt spike,” Skrabak said.

The plan was endorsed by the board of Alexandria Renew Enterprises, which cleans dirty water in the city before discharging it into the Potomac. The Hoofs Run tunnel would allow greater integration with AlexRenew’s treatment plant on Eisenhower Avenue.

“The combination of complementary approaches to reduce combined sewer overflows and mitigate overall wet weather impacts to the AlexRenew facilities from the city collection system obtains the greatest environmental benefit and helps minimize long term operational and cost impacts to AlexRenew, providing more sustainable rates and infrastructure management,” AlexRenew board chairman John Hill wrote in a letter to city councilors.

There are four possible sites for the tank under Royal Street, including on private property, in the right-of-way or on land owned by the National Park Service at Jones Point Park. Skrabak said staff will continue to evaluate all four options, and there currently is no preferred alternative.
In its report, staff suggested waiting on other projects before moving to improve discharges at Pendleton into the Potomac, but councilors and members of the public who testified expressed a de- sire to see faster progress.

“The other issue is we’re talking about a lot of activity along the waterfront, and here is this source of pollution that of course dates back to the 19th century,” said Mayor Allison Silberberg. “It’s the right thing to do. It’s our river, we share it with others.”

“For decades to come, it will release raw sewage past three of our major parks, the city marina, residences, the planned new development on the waterfront, Jones Point Park and on down the Potomac,” said resident Jack Sullivan.

Skip Maginnis, chairman of the combined sewer sys- tem stakeholder group, expressed reluctance to put too much pressure on city financial and work resources.

“These are major public works projects, and even if you had the money now, just kicking off what would be three major, huge public works projects simultaneously is just logistically, practically, from a staff resources point of view, a huge lift,” he said.

In its approval, council directed staff to return with proposals on how to expedite the planning process for improving the Pendleton Street discharge area. City Manager Mark Jinks must submit the updated long-term plan by August 23, something Silberberg said was necessary as the city looks to minimize pollution and harm to the environment.

“This has been festering for decades, and we intend as a council to move forward on it,” she said. “There’s been a lot of discussion and a lot of planning, and this is a huge step forward, not just because it’s been mandated by the [U.S. Environmental Protection Agency], but because it’s the right thing to do.”