MnDOT plans to replace aging bridge

Lyon County commissioners hold hearing for box culvert on Highway 91

Photo by Deb Gau Lyon County Auditor/Treasurer E.J. Moberg and Allen Schmitz of the Minnesota Department of Transportation answered questions about a proposed bridge replacement on Highway 91. MnDOT planned to replace the bridge with a box culvert, and needed to file a ditch petition in order to move forward with the project.

MARSHALL — The Minnesota Department of Transportation is proposing to replace an aging bridge on Highway 91 in southern Lyon County, county commissioners learned Wednesday.

The plan is for a box culvert to take the place of the bridge, but MnDOT representatives said that shouldn’t mean much change in the flow of water in a county ditch.

On Wednesday, the Lyon County Board held a public hearing on a petition from MnDOT to make minor alterations to County Ditch 13, branch 6. The petition needed to be granted before MnDOT could replace the bridge.

Allen Schmitz, of MnDOT, and Lyon County Auditor/Treasurer E.J. Moberg were at the hearing to answer commissioners’ questions about the ditch petition. Schmitz said the plan was to replace a span bridge on Highway 91, near the intersection of Highway 91 and 140th Street.

“It’s run its life,” Schmitz said of the bridge.

Instead of replacing the bridge with a new span, MnDOT would put in a reinforced concrete box culvert 14 feet wide and eight feet high, which would rest on the bottom of branch 6 of County Ditch 13. The box culvert would be much less expensive than building a new bridge, he said.

Schmitz said MnDOT contacted Todd Hammer with the Lyon County planning and zoning department before filing the petition to make changes to the ditch.

Commissioner Charlie Sanow asked how the culvert would affect the flow of water in the ditch.

Schmitz said the box culvert should have a flow “pretty similar” to current conditions. “It’s probably going to be a little less,” he said. However, he said a hydraulic analysis of the proposal found that the stage of the ditch would rise about two-tenths of a foot in a 25-year rain event, and six-tenths of a foot in a 100-year event.

A 100-year event for the ditch would probably be about six or seven inches of rain falling in a 24-hour period, he said.

Part of the ditch petition from MnDOT included terms that the alterations to the ditch in the project “will not affect the functioning nor impair the efficiency” of the ditch.

In response to a question from Sanow, Schmitz said project costs, as well as the cost of advertising fees for the hearing, would be paid by the state and not the ditch.

Although commissioners opened the hearing up for comment, no members of the public made any comments on the proposal.

Commissioners voted to approve the ditch petition.

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