In what is being described as tedious and labor-intensive work, DC Water contractors are removing layers of hard rock at the bottom of a manhole they are trying to excavate to 42 feet. They hit the rock at 30 feet and as of August 22nd, were halfway through.
Workers at least three stories under street level, excavating a sewer manhole just east of Connecticut Avenue on Albemarle Street. (DC Water photo)
The manhole in question is in the closed section of Albemarle Street east of Connecticut Avenue. Its excavation is part of the final stage of DC Water’s Soapstone sewer rehabilitation project. And that layer of rock is one of two reasons the agency is giving for the latest project delays.
DC Water had a three-month timeline for this phase when it closed the street last September, but the manhole held many surprises, including a large storm drain that no one knew was there, and had a cascading effect on the planning.
Another surprise discovery is still holding up the project: a ten-inch sewer pipe that wasn’t on any infrastructure maps, old or new. It’s believed to originate at Avalon the Albemarle (4501 Connecticut Avenue).
“We have found couple of illegal connections to our system, we suspect this may be another one,” DC Water’s Peter Tinubu wrote in an August 22 email to Forest Hills Connection.
Tinubu, the head of the project, says the sewer pipe likely dates back to the construction of the building [in the late 1950s]. DC Water needs to know where the pipe enters the building so it can control the flow of sewage for the last of its sewer relining work in the Soapstone Valley. And, “Avalon has been trying without success to find the as-built drawing.”
DC Water has done its own digging, with Avalon’s blessing, in a grassy area near the parking entrance, and has also had little success.
It’s that sewer connection – and not the rocky layer – that Tinubu says presents the greatest challenge to meeting DC Water’s projected September 11th project completion date, set in late May. Now, he says, mid-to-late October is more likely.
The final segment to be relined is a 325-foot pipe that flows from Albemarle Street into the park. Once that’s done, DC Water can begin to reassemble the manhole and the street.
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Tom says
Thank you for covering this issue so diligently and thoroughly. It’s so nice to know what’s going on, and it’s also quite interesting.
Diana Hart says
We are beyond lucky that the valley within Rock Creek Park allowed us to tamper with its natural beauty. The price is still not fully paid.
Barbara T says
Just wondering how the Avalon builders got through that extreme depth of rock to install that “illegal” iron pipe if indeed they did. I suppose digging down to the depth of the creek and then boring. more or less horizontally? How they could have done that illegally in the 1950s beggars belief.. Of course I know nothing of the technicalities involved!
FHC says
Apologies for not making it clear in the article: DC Water is digging deeper than the original manhole, which is decades older than the Avalon apartments.
Marchant Wentworth says
Thanks so much for both reporting and photography. There are lessons from Soapstone for the rehab of other dirty tributaries including Pinehurst, Portal and Luzon. One: expect surprises, especially when dealing old pipes. Discovering the “illegal” pipes, it may be a small bit of good news for water quality of Rock Creek when corrected. Cheers Marchant Wentworth, Wentworth Green Strategies
P.S. Historically plumbers sometimes made honest mistakes and connected their pipe to a sewer line. But my guess is that the connection was made to whatever was nearby, quick and cheap. After all, lacking decent oversight, who would ever know (Except the Creek, of course).
Paul W says
Maybe it’s better to not set anymore deadlines. When it’s done, it’s done. And then, DC Water should throw a block party at the site where we can all celebrate Albemarle’s return-to-service.
Jay says
No existing records at all for a drain pipe from a building this large into the city sewer system? Hard to believe that a diligent search of government or private records (contractors involved) wouldn’t turn up something. But in any event, if the problem is finding out “where the pipe enters the building”, it’s obvious that you start searching by opening up some major drain lines within the building and then finding out the “route” that leads out of the building — that’s precisely why a radio signal detection system, a drain camera with a radio signal, ground penetrating radar, and a robotic crawler with GPS transmission are used to detect the route taken by buried pipes. This is not rocket science, but it requires careful planning to use the right system(s) and excellent plan implementation for precision tracking. The handling of this entire project from the beginning suggests that careful planning and excellent plan implementation have been lacking.