Flooding continues across Midwest; how ND DOT mitigates potential flooding problems

BISMARCK, N.D. (KFYR) – Flooding has been devastating in parts of the Midwest recently, impacting the Blue Earth River in southern Minnesota, leading to the closure of I-29 in parts of South Dakota and Iowa, and causing millions of dollars in damages to small towns and farms.

While rainfall for many in North Dakota has been above normal, flooding problems haven’t been widespread.

The North Dakota Department of Transportation (DOT) tries to prevent problems each year with proper planning for projects.

“Anytime there’s a project that impacts a stream crossing— so that can be a pipe, a box culvert, a bridge— we have to do the hydraulic design to ensure that the minimum opening is met. North Dakota state law has specific requirements of what design event these different types of crossings need to be built to, they are dependent on the roadway classification. So, for instance, our interstate is our highest priority, so it has a larger flood event that we design it to, to help ensure that there’s resiliency for that roadway,” said Lindsay Bossert, assistant bridge engineer at the ND DOT.

The DOT follows strict design standards, going above state law by planning for 100-year flood events, especially when bridges are involved.

“We have a lot of bridge replacement projects, those we have to design hydraulically to make sure that that opening size is large enough to accommodate these floods. So, a lot of those projects are going on right now,” said Bossert. “We’ve also done quite a bit of grade raises over the past few years. So, we have specific roadways that we see inundate, go underwater quite frequently. So, we’ve really tried to start bringing those above where we see that flood typically occur to ensure that those stay dry.”

I-94 recently flooded from heavy rain near Cleveland, west of Jamestown.

“We are now looking at the hydraulics of that, trying to figure out how high we would need to bring that road up in order to ensure that that flooding doesn’t occur again,” said Bossert.

Being able to rapidly respond to flooding situations starts with preparedness within each DOT district.

“They visit with their maintenance crews early spring, make sure they’ve got all their signs and barriers ready to go so that we can react quickly if we need to shut down a road. Once the spring melt starts occurring, we typically pay close attention to the water levels at that site. We use USGS stream gauges or cameras to kind of help us track those water levels,” said Bossert.

Safety comes first, so road closures do happen sometimes and damage inspections are required once the water recedes.

Flooding can also delay ongoing construction projects, so DOT contractors need to maintain positive drainage throughout the construction site to mitigate these problems.

Eastern North Dakota is generally the most problematic for flooding. River levels remain high there and across much of the Midwest, with a bit more rain to come before dry conditions are expected in the longer term.

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