DC Water’s Soapstone sewer relining work well under way; 2nd stage to begin in May

by Marlene Berlin

The relining of the 115-year-old Soapstone Valley sewer has advanced by leaps and bounds since that phase of the sewer rehabilitation project began in mid-March.

The pipes that carry raw sewage through and around Soapstone Creek, predominantly on National Park Service land, are years beyond their expected life span. They are being relined using cured-in-place pipe, or CIPP, which is designed to stop and prevent leaks, and extend the pipes’ useful life for several decades.

At the April 18th ANC 3F meeting, DC Water officials said that the segment between Broad Branch Road and Audubon Terrace (Sites 4 through 6 on the map below) had been completed, but that three of the five sections within the segment, called “shots,” were still undergoing closed-circuit camera inspection and review.

DC Water’s April 2023 Soapstone sewer site map. The words “70% complete” and “Upcoming” at Sites 4, 5 and 6 refer not to the CIPP work but to stream rehabilitation and rebuilding designed to protect the sewer infrastructure from erosion. (Click the image to view a larger version.)

By Sunday, April 23rd, sewage could be heard flowing through the completed segment.

To perform the CIPP work on the first segment, DC Water had to construct and activate a bypass sewer system. The sewage was then rerouted and pumped through the temporary system with a pump situated on Audubon Terrace. Once the pipe was cleared of sewage, a closed-circuit camera was inserted into the sewer to evaluate the interior and check for debris, which was removed.

A contractor clears debris from a pipe. (DC Water photos)

Then, the soft plastic liner was inserted and hardened, or cured, with hot water.

Prepping a manhole for liner intallation.

Inserting the liner.

This process required a reefer truck, which carried the liner, and a boiler truck, which heated the water. Each took turns driving back and forth over a temporary roadway to reach the various shot sites.

Reefer (refrigerated) truck with liner.

Boiler truck on an access path.

While this was taking place, air quality was monitored, according to a plan approved by Stephen Ours of the Department of Energy and the Environment (DOEE).

Peter Tinubu, DC Water’s Soapstone project director, confirmed in an April 24th email to Forest Hills Connection that sewage was no longer being routed through the bypass. He explained that DC Water reviewed CCTV footage of the completed segment and found “no visual issues.” Then, the bypass was turned off and the flow returned to the relined sewer pipe. The bypass will remain where it is, Tinubu wrote, “until the curing logs and lab rest results of the installed material are verified according to specifications and the liner is accepted for long-term use.”

Tinubu also reshared the tentative schedule DC Water gave to ANC 3F commissioners on April 18th, with the bypass being dismantled the week of May 1st, and being moved to the next segment the week of May 8th. Following bypass installation and testing, the preliminary CCTV inspection of the next segment could begin as soon as May 22nd.

ANC 3F Commissioner Mitch Baer, whose single member district includes the park, has requested that DC Water provide additional information about the bypass at the May ANC meeting. Unlike other DC Water projects, DOEE is not requiring permits for the bypass system that is carrying sewage through Soapstone Park.