Montebello sinkhole nears repair

When Baltimore officials first spotted it in November 2022, the sinkhole in the grass beside Lake Montebello was about the size of a basketball.

Officials said the repair would take weeks, but weeks became months and months became nearly two years.

To fix it, city workers ended up excavating 7,500 cubic yards of soil (about 750 dump truck loads), creating a small canyon beside the drinking water lake in Northeast Baltimore and shuttering a chunk of its popular walking loop.

After numerous delays, city officials say the saga is nearly complete. They’re confident that the massive crevasse will be filled this fall, reopening the full 1.3-mile path to visitors long frustrated by its dead ends near the sinkhole site.

The project is yet another poster child for Baltimore’s struggles with aging infrastructure. The cause of this multimillion dollar project is the failure of an underground storm drain built nearly 150 years ago when Ulysses S. Grant was president with hand-laid bricks.

Batimore has 1,146 miles of stormwater drains, most of which were built before 1950, as the city diverted its once vast network of streams and creeks into underground pipes, clearing the way for rapid development.

In July 2022, a 115-year-old storm drain made of stone collapsed along North Avenue, creating a sinkhole that ultimately forced the demolition of several homes. That incident was the first domino to fall in a series of old water infrastructure failures, which the city believes briefly caused E. coli bacteria to be detected in West Baltimore taps in September of that year.

“These things have been happening under our feet all the time, and it’s really only when they collapse and disaster strikes that we realize,” said Alice Volpitta, the Baltimore Harbor waterkeeper, who closely follows stormwater issues in the city.

Development has brought more impervious surfaces into Baltimore, which can’t soak up rainwater, sending it gushing into the buried streams and their aging pipes, Volpitta said. And climate change, she said, promises to increase the intensity of storm events, potentially overwhelming the drains further.

“These pipes, to begin with, were designed for a city that no longer exists,” Volpitta.

Timothy Wolfe, the engineering office chief for the Baltimore City Department of Public Works’ Water and Wastewater Bureau, starts the Lake Montebello sinkhole’s story in July 2020, when damaging flooding near the reservoir along Hillen Road swept away cars and trapped an MTA bus.

“It was a pretty bad situation, so we went in, we said we’ve got to do some investigation to determine what the cause is,” Wolfe said.

Ground zero was that storm drain from 1876, which used to be a stream called the Tiffany Run, a tributary to Baltimore’s Herring Run, which feeds into the Back River and then the Chesapeake Bay.

In July 2021, Wolfe and other officials walked into the storm drain for an inspection, and discovered that a 70-foot section had sunk about 15 feet, causing bricks to fall into the pipe, Wolfe said.

Back then, it was “stable, but concerning,” Wolfe said.

The city commissioned engineers and contractors to address it, but as they prepared to begin work, the sinkhole opened about 50 feet above the drain, and it began to fail.

Of greatest concern was a massive water main, 7 feet in diameter, routed through the soil above the Tiffany Drain. If the drain collapsed, so could the drinking water pipe, interrupting water service to thousands of customers in eastern Baltimore city and county.

“That’s when we decided to switch gears and really prioritize this,” Wolfe said.

It was a “touch and go” period, said Councilwoman Odette Ramos, who represents the area. Ramos praised DPW’s “cautious approach,” which kept workers safe and ensured reliable water service, but did require residents’ patience. Even now, Ramos said she’s hesitant to give residents a concrete date for the project’s completion.

“I’ve not been giving people timelines, because I don’t want to get peoples’ hopes up,” Ramos said. “When it happens, that’ll be great, and we’ll have a big party.”

The water line issue was the project’s first intermission: In about six weeks, the city obtained a replacement 48-inch water main, hooked it up to the system, and ran it above ground to bypass the sinkhole so the work could carry on.

But once the construction crew began excavating the soil, they hit a second speed bump. As the crews dug deeper, the soil began to shift dangerously, requiring them to move the newly installed water pipe further away from the site, right beside a building at the Montebello Water Treatment Plant, which was then closed to workers due to the safety concerns.

The unstable soil also required construction crews to install a massive stabilizing wall on the hillside as they burrowed deeper into the soil. That took another nine months.

Finally, workers could excavate deep enough to reach the Tiffany Drain, and replace the collapsing section of the historic brick structure with a large, 110-inch diameter pipe made of polymer mortar reinforced by fiberglass. They expect that the new pipe will be hooked up to the system, and the whole area will be backfilled with soil, around the end of October. Then, the city will begin plantings on the site to restore the area, which formerly hosted disc golf holes, according to DPW officials.

“We like to show off the project, so they can see just how complicated it is,” said Cherod Hicks, a DPW engineer who led the project. “It goes to speak to what the engineers and our craftspeople were doing over a hundred years ago. If you look at the masonry around that pipe, it’s beautiful.”

Hicks estimates that his crew worked about six days per week, and 10 to 12 hours each day to get to this point, working around rainstorms that would fill the tunnel and make construction work impossible for 24 hours at a time.

“If it rains in Baltimore County, and Baltimore County gets a quarter inch of rain … this will be about 80 to 85% full,” Hicks said of the storm drain. “If it rains in the city with, really, a two-year rain event, this is basically at full capacity.”

The inundations of the stormwater system are a powerful reminder that rain gardens and swaths of greenery in an otherwise urban setting are a critical part of stopping infrastructure failures before they happen, Volpitta said.

“These streams under our feet are basically coming back to life,” she said, “and they’re letting us know that they’re still there, through flooding and some serious infrastructure damage.”

There are plenty of other occasional reminders that the Tiffany Drain was once the Tiffany Run, like the small fish and water snakes that Hicks has spotted in the trickling water of the drain pipe.

The ordeal was a personal project for Hicks, who lives close enough to the project site that he can see it from his bedroom window.

“I also have a personal impact, because if we lose the 84-inch water line, I personally won’t have any water. I understand the inconvenience to not be able to use the full loop of the lake,” Hicks said. “Some of my best conversations and times with my family and friends are walking the full lake loop.”

Though the loss of the full loop has been frustrating, some residents say they’ve adapted to the change.

Gail Geller and JoAnne Kraus, two local lake-goers, have made a ritual out of walking from one dead end to the other, tapping each set of barriers before turning around, they said. Both live within a few miles of the lake, and meet there weekly to walk. From the lakefront path, they’ve watched the project run its course, including the creation of a massive pile of excavated dirt.

“It’s been annoying,” Geller said. “But it’s been interesting to watch the evolution.”

On Tuesday afternoon, the lake path buzzed with dogwalkers, families pushing babies in strollers and even a impromptu karaoke station inviting passerby to sing.

But, at least anecdotally, one group of people have seemed to be using the lake path a bit less: bikers.

“I think the bicyclists miss being able to zip around at a high speed,” said Lisa Hansen Terhune, a resident of the Mayfield neighborhood beside the lake and a board member of the Mayfield Improvement Association. “I’ve just also noticed maybe a few less groups of people — there used to be a lot of boot camps and ad-hoc exercise groups.”

With the project’s finish line seemingly in sight after a number of delays, there comes hope that all of the lake’s visitors will return.

“It’s a great asset for the city, and for any time: morning, midday and early evening,” Terhune said. “I think having it open around fully will bring more people back.”