HIGHLAND TWP. — The failure of a large diameter culvert has caused 70th Avenue over Crocker Creek to close indefinitely, according to the Osceola County Road Commission.

The crossing is located approximately one-fourth of a mile south of 20 Mile Road and four miles west of Marion in Highland Township. A detour has been established directing traffic west on 20 Mile Road to 80th Avenue, then south on 80th Avenue to M-115, and then M-115 southeasterly back to 70th Avenue.

According to the road commission, problems with the culvert were first discovered last summer when a large hole developed in the road above the culvert. After investigating the situation, it was determined several cracks in the sidewall of the concrete pipe had allowed water to get behind the pipe and wash out the sand backfill around and above the pipe. A geotextile fabric was placed on the culvert prior to replacing the backfill to minimize additional loss of material. An engineering firm, Link Engineering Services of Traverse City, evaluated the structure, resulting in a recommended maximum three-ton load restriction and continued monitoring for any additional distress to the culvert.

A complete repair was not an option due to a lack of funding, so the commission repaired what it could, and Road Commission Manager Luke Houlton said through the fall, the culvert was monitored every couple of weeks and reassessed.

An inspection late last week revealed a approximately 2-by-3-foot chunk of the concrete culvert side wall had completely broken away over the winter, leaving little support of the remaining concrete above it. Nothing but the fabric placed around the pipe was holding the dirt from washing away and undermining the roadway.

The structure was sound until recently, and Houlton believes the winter freeze caused the cracks to expand. Once spring temperatures caused ice to thaw, the cracks were large enough to create the damage.

As a result, the road has been closed until such time as a replacement structure can be installed.

“Unfortunately, we will not be able to replace the culvert with a similar size,” Houlton said. "The Michigan Department of Environmental Quality permit needed to complete the work will require a much larger opening. We will have to replace the existing eight-foot diameter culvert with a 22-foot long bridge."

Link Engineering is currently working to develop construction plans and a cost estimate to replace the culvert. While the plans are not yet complete, the preliminary estimated costs are upwards of $375,000. Until the commission can identify and secure a source of funding for the replacement the road will remain closed to traffic, Houlton said.