Public works director Josh Snyder discussed the situation at this week’s city council meeting.
Snyer said he became altered to the problem after noting a $13,000 guardrail in Norwalk was “starting to give out.”
“It’s a cause for concern,” he told council.
“There’s a dip in the guardrail,” Snyder said.
“We noticed it three years ago and cut back the overgrowth around it. That opened up that view, if you will, ... to really expose the guardrail sinking. So we visually monitored it. Then last year I took some grade shots and the measurements showed that from September to March, the worst area of guardrail had moved 2.5 inches in 6 1/2 months.
“Is it something that’s imminent? Sure, eventually. Is it something that will happen catastrophically? No, I don’t think so.”
Because of all of the unknowns, Snyder said the department hasn’t alerted the surrounding homeowners, noting they first want to know if the issue will effect the surrounding properties.
“Until we know where the failure plate is, we don’t want to get anyone excited and go, ‘Hey, it’s all on your property.’ It may or may not be,” the public works director said.
If the assessments show that the movement is entirely on the homeowner’s property, Snyder said it would be up to the homeowner if he or she were concerned enough to take action.
“They may not even care,” he said. “We don’t want to alarm them though at this point. ... It’s definitely a thought though if at any point we need to reach out them.”
Snyder said the sinking is likely the cause of two different types of soil existing in the area, probably one on top of the other, causing them to shift away from each other.
Though soil-shifting is causing the guardrail to move, Snyder said there’s no concern at this point over the safety of the nearby road, which remains open.
“The roadway itself is not moving, but we’re monitoring it,” he said.
Tests and assessments will help the public works department determine just how deep that layer of difference is and how far it extends around the area. He said current evidence shows the area is about a 70-foot section that is effected. However, the assessments could reveal a larger or deeper area effected.
“Maybe we’ll just have to dig out a layer,” he said.
If the shifting area is small enough, Snyder said it would be “no harm, no foul” situation and the guardrail could simply be moved in closer to the roadway since it’s currently about four to feet feet away.
“Unlikely, but that is probably the best case scenario of what we might find,” the engineer added.
Snyder said his fear is the worst-case scenario — a job similar to what took place at the lift station.
“My fear would be the worst, and that would be that we need to put sheet piling down there, which would be like clear cutting the whole side of the hill and driving in full sheets of metal like we did on Pleasant Street for the lift station,” he said. “That’s what I hope to avoid because that’s going to be the most costly resolution to that kind of an issue. It can only get better from there resolution-wise.”
Once the surveys are done and a contractor found, work on the soil could begin within the next month. The extent of the project though won’t be known until results are gathered.
“There are a lot of variables still,” Snyder said.