Hillside trail closed due to tumbling rocks
Feb. 5—EAU CLAIRE — A segment of the city's recreational trail closed last week due to rocks falling off a neighboring hillside and rolling onto the asphalt path.
Located alongside the North Crossing, the trail is now slated to be moved farther away from the hillside this year while a slight depression is dug to trap any rocks that fall in the future.
The work will be a joint effort of the city — which built the trail and handles its upkeep — and the state Department of Transportation — responsible for Wisconsin's highways, including the North Crossing.
"We kind of both have responsibility to mitigate those safety concerns," said Tim Mason, the department's operations chief for northwest Wisconsin.
State and city officials first became aware of rocks tumbling onto the trail late last year. That led to cautionary signs warning people who use the trail section along the North Crossing, between Abbe Hill Drive and near La Salle Street, to beware of falling rocks.
Dave Solberg, deputy city manager and engineering director, said there have been no reports of injuries from the fallen rocks, but they did pose a safety concern for trail users.
"It's still a hazard for ADA accessibility to have rocks on the trail," he said.
On Tuesday — the same day the trail was barricaded — Mason and Solberg held a joint meeting with Eau Claire County Highway Commissioner Jon Johnson to discuss a project to mitigate that hazard. (The county is hired by the state Department of Transportation for winter maintenance of state highways and some other work as well.)
"What we've proposed is realigning a portion of the trail away from the rock face," Mason said.
There's enough land between the highway and hillside for the trail to be shifted closer to the roadway, but still keep a safe distance away from traffic lanes and provide enough land to plow snow onto during winter.
Closer to the hillside, a trench or swale would be dug to contain any more rocks that break free and fall off due to weathering.
Mason said the south-facing rock hillside has been susceptible to erosion because it gets exposure to sunlight during winter. This leads to water in the hillside thawing during the day, freezing at night — a cycle of expansion and contraction that results in rocks occasionally flaking off. He noted that the same erosion has not been observed on the opposite hillside also carved for the North Crossing, due to its northern exposure.
The next step in the trail realignment project is expected to be an on-site review, which Mason said will probably happen in March. After that, he anticipates the work would be done in late spring or early summer.
It's not expected to be a large undertaking. The rough estimate for the work is about $20,000, though Mason said that will likely change as the review is done and the length of the new trail section and digging is finalized.
Work and the costs for the project are expected to be split between the city and state.
"It's a little of both," Mason said.
