The West Memorial Boulevard railroad underpass between South Potomac Street and Maryland Avenue has been closed for almost two months as city officials have searched for the source of persistent flooding that occurs during heavy rains.
After extensive investigation, the cause of the flooding appears to be a nearly 100-year-old stormwater pipe beneath the roadway that has become blocked, or possibly broken, somewhere along its path toward the east end of the city, according to Eric Deike, director of the Hagerstown Public Works Department.
The 15-inch vitrified clay drainage pipe, which Deike estimates probably was installed around 1917, lies directly below a 27-inch sewer line, which has caused headaches in identifying the issue and finding a solution.
Because it’s such an old pipe, Deike said, the joints between sections aren’t properly sealed, allowing dirt and silt to fill up inside from groundwater runoff and possibly for tree roots to grow through the pipe and cause more issues.
“They installed it in a way that they planned on never going back. That’s for sure,” Deike said this week. “And it worked for a long time, but unfortunately, it’s time to do something different.”
Deike said the pipe runs east from Hagerstown’s City Park along Marsh Run toward Municipal Stadium, ultimately emptying into the run and then Antietam Creek, but what makes the task so difficult is that there are no access points to the pipeline.
Deike said city workers are excavating the ground alongside both pipes and installing manholes about every 1,400 feet. Then, 45-degree angle joints and silt boxes will be placed down in the manholes to allow access for maintenance of the pipes in the future.
But before that, workers must break through the side of the stormwater pipe and insert a “flusher line” that will help clean out the suspected large amounts of debris and use a camera to inspect the interior of the line, Deike said.
Making it even more difficult, Deike said the upper sewer line is encased in concrete and the entire pipeline area is surrounded by solid rock, causing the need to chisel out extensive material to reach the lower pipe.
“We’ve done that from the underpass at Memorial Boulevard to approximately 2,100 feet east toward the stadium,” he said. “So we’ve opened all that up, we’ve been able to clean that open and we’re pretty confident that’s in good shape.”
Deike said he hopes to have most of the rock removed by next week so crews can move forward with manhole installations.
Many man-hours have gone into trying to identify the “frustrating” problem, Deike said.
The public works staff has received help from the city’s electric, wastewater and engineering departments while trying to find the root of the flooding and then determine the best solution, he said.
On top of that, the project might end up being a little costly, as the city has had to enlist the services of local contractors to help with excavating in addition to installing new silt boxes and angled pipe joints, Deike said. He did not have a cost estimate yet.
Although two to three weeks was Deike’s initial estimate of when that section of West Memorial Boulevard would reopen, he erred on the side of caution, admitting that it most likely will be closer to three weeks, depending on “what else we run into.”
Once the area near the underpass is completed and crews move further down the line, the project appears like it will progress more smoothly because most of the pipeline runs along the north side of Marsh Run in grassy areas, rather than under streets, as it moves east, Deike said.
“Memorial Boulevard is a priority to get open,” he said. “It’s just been one of those projects that we’re playing it as we go. We’re finding out all new things.”
The underpass has been closed since May 29. City workers began draining water from the street when floodwaters would not recede, a city official said previously.