Failing bridge abutments discovered
By John Faucher
Village Public Works Director Carl McCrary informed the village board Thursday, May 21 of a delay with the Black Otter Lake Dam project.
Lunda Construction was forced to stop work on the dam due to the need to stabilize the County Highway M bridge abutments.
“There are serious erosion issues behind and below the bridge abutment wall due to water seeping behind them over the years,” said McCrary.
The existing dam structure was built in the late 1800s.
When Lunda began removal of the existing structure, they discovered the original ledge rock and stone abutments had large voids.
“We didn’t have any indication that there would be issues there until we started excavating next to the bridge footings. We didn’t realize the extent of which they used field stone,” said McCrary.
“When the bridge was built in the 1940’s they poured the concrete on top of the original abutments. We are currently waiting on an approved design stabilization method needed to support the failing bridge abutments. It’s going to delay the project three to four weeks,” said McCrary.
The project completion date was early August, but may now be delayed until early September.
The village’s engineering firm has contracted the services of a geotechnical specialist. McCrary said, “We’re expecting there to be some temporary measures performed before work can continue (such as concrete injection) and likely a separate permanent earth retention structure to solve this issue. We cannot quantify this impact until we know how and when to proceed.”
He informed the village board that a verbal agreement existed between the county and village to share the cost of fixing the abutment, although the details of an agreement have not been formally approved.
Some funding for the change order may also come from the Wisconsin DNR Municipal Dam Grant Program.
The village started the process of seeking a grant for replacement of the Black Otter Lake Dam in 2010. The DNR completed a dam failure analysis and rated it as a high hazard dam. The village had two options, either repair or remove.
Removal of the dam would mean the loss of Outagamie County’s only lake.
The Village applied and received a grant through the DNR’s Municipal Dam Grant Program. The grant will fund 50 percent of the first $400,000 for the new dam.
McCrary said he will have to submit a change order request to Madison for the grant, and hopes to secure some additional funding for fixing the abutments.