The nondescript bridges are tucked in rural corners of Dakota County, straddling dry ditches and creek beds. They are barely noticeable to the average driver, but are always on the county’s radar.

“We watch the bridges really close. It’s important that we don’t let them get structurally deficient,” county engineer Mark Krebsbach said.

Three of the county’s 81 bridges will be replaced this summer and early fall. Four more replacements are planned next year, though those could be postponed if they do not meet state funding criteria, Krebsbach said.

This summer’s replacements are estimated to cost $1.5 million, design engineer Tom Anton said.

The closure of County Road 46 over the Vermillion River near Hastings will have the greatest impact on traffic. There will be a marked detour in the area.

The other two bridges, which are small and made of timber, will just briefly close. Those bridge replacements are straightforward projects and will take a couple of weeks to complete, Krebsbach said.

“You just want to make sure that we’re finished up in advance of any of the fall harvests,” he said.

The two timber bridges are some of the last remaining in the county. The county has been replacing the timber bridges with concrete as they age. Timber is unpredictable and difficult to inspect, Krebsbach said. The outside of the logs may look fine, but inside the wood can be rotten.