Walls come tumbling down 

Retaining walls don't attract much notice — until they fail

In early May, three homes on the city's west side were evacuated as more than 10 one-ton concrete blocks slid toward them down a muddy hill.

The blocks tumbled from homeowner Stephen Hennings' private retaining wall, built in violation of a permit, at 1605 S. 26th St. According to records of the Pikes Peak Regional Building Department, it wasn't Hennings' first run-in with the department. It was only after someone reported him to RBD in 2007 that he got a permit for a garage he was building. And complaints about his retaining wall — permitted for 20 feet high, but built to approximately 36 feet — date to 2002.

"That was engineered for a 20-foot [tall] wall, and it will work for a 20-foot wall," Roger Lovell, RBD's director of building operations, says. "But if you're going to go 36 feet, you need different engineering."

Hennings' wasn't the only retaining wall that failed in the wettest month on record in Colorado Springs. One collapsed near a car dealership on Motor City Drive. Others fell into North Rockrimmon Creek, along with a couple decks, and substantial portions of two backyards. In Manitou Springs, two publicly owned retaining walls fell apart, one on Manitou Terrace, the other on Spencer Avenue. Multiple private retaining walls — many built at the same time as the area's historic buildings — also succumbed to water pressure as soils expanded with rainwater.

Unlike Hennings' wall, these structures were either properly permitted or built before permits were required. But, in all likelihood, they weren't inspected recently. The cities of Colorado Springs and Manitou Springs, as well as El Paso County, do not regularly inspect or maintain public retaining walls that aren't associated with bridges. And the RBD doesn't inspect private retaining walls after they're built unless it gets a complaint.

That's a flimsy safety net as it is. But even when a private wall is identified as unsafe — as Hennings' was in 2014 — there's little that can be done to force the owner to immediately fix the problem.

No one knows how many retaining walls there are in the county, or even in Colorado Springs or Manitou Springs.

The closest thing to a record is RBD permits, which are issued before private walls, over 4 feet tall, are built. Since 1983, Lovell says RBD has issued at least 1,242 such permits — though it's likely that some weren't incorporated into the current database.

Despite the ubiquity of retaining walls, Tim Mitros, a 23-year city employee and Colorado Springs' stormwater manager, says, "I can't even think of when I've had someone call me up and say you need to look at this retaining wall."

"Except," he adds, "that one [owned by Hennings] on 26th Street."

El Paso County Engineer Andre Brackin says he can't think of any county retaining walls that have failed.

Built right, he says, a retaining wall can outlast most people. But like any structure, their lifespan depends on how they're built. A wall built of railroad ties isn't likely to last as long as one made of concrete blocks, but even a concrete block wall can fail early. A lot of factors play into lifespan including: the soil type behind the wall, drainage around the wall, the material the wall is made of, and how strong the wall's foundation is.

"There's a lot of different ways to design [walls]," he says. "Ensuring that there's low water and water pressure behind [the wall] is critical."

Lovell says building a wall that will last is actually fairly complex. That's why higher walls require engineering and soil reports.

"The taller you go on a building the more robust the bottom pieces of the building have to be," he says. "It's the same with a retaining wall."

Shelley Cobau, Manitou's flood recovery manager, says because so many factors play into making a wall strong, there are also multiple ways it can fail. In the case of the Manitou Terrace wall, she says "weep holes" in the wall that allow water to drain through it became clogged. Water pressure built behind the wall, which collapsed from the top.

When a retaining wall is deemed dangerous, or when it fails as Hennings' did, the city of Colorado Springs can ensure it's fixed — at some point.

Based on complaints filed with the RBD, it's likely that Hennings began building his retaining wall before the accompanying house, which was permitted in 2003.

Three complaints about the wall were lodged in 2002. Lovell says his department responded to those initial complaints, but Hennings told them there would be no more than 4 feet of wall above ground and thus no permit was required.

In November 2013, another complaint rolled in, indicating the wall was getting taller. RBD inspectors checked the wall again, and Hennings again told them it would not be higher than 4 feet. But a few months later, in April 2014, Hennings obtained a permit for a 20-foot wall, along with the required engineering and soil reports.

When the department again received complaints, an inspector visited the site and found that Hennings had built the wall approximately 16 feet higher than permitted, and had not asked for nor received proper inspections during the building process. In July 2014, the RBD filed a "stop work" order, issued Hennings a Notice of Noncompliance and voided his permit. Hennings did not respond.

On Dec. 5, RBD went a step further, issuing a Certificate of Noncompliance, which notifies the owner that property cannot be sold or refinanced until the issue has been resolved. It's the last hammer RBD had. But Hennings' wall didn't go anywhere — at least not until May, when it began sliding off the side of the hill.

On May 7, the city of Colorado Springs — which has a few more hammers at its disposal — ordered Hennings to dismantle his wall. He was cooperative, but city spokesperson Kim Melchor says the continued wet weather prevented him from working on it immediately. It wasn't until May 16, Melchor confirms via email, that Hennings was able to get the wall "to a level that the City determined to no longer be a threat to safety and property."

The Independent left a message at a number listed for Hennings, but he did not return the call.

Melchor writes that if Hennings hadn't responded to the city order, the city could have taken corrective action and dismantled the wall if there was "an imminent threat" in order "to protect life and property." But in any such situation, the city must give property owners a "short time" to act on their own — depending on the particular situation.

She adds that in general, when faced with a dangerous structure, "[W]e work to implement the minimal action required to achieve the desired result and protect life/safety. For example, you don't always have to tear down a dangerous abandoned building, but posting a fence and signage may be determined to be a feasible solution."

The city didn't leave the situation completely up to Hennings — it took steps to protect homes from the falling blocks. Melchor says the city hasn't yet decided whether to attempt to recoup the costs of those measures. There also has been no indication whether any residents who were evacuated might take legal action against Hennings.

  • Retaining walls don't attract much notice — until they fail


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