While officials said little change is expected to come from a flood plain study that was supported Monday by Union’s Planning and Zoning Commission, a second study might be more noticeable.

The new study, which could be years away from completion, currently proposes to raise the base flood elevation to 519 feet above sea level from the current 515 feet in the flood plain around the Bourbeuse River near the intersection of Highway 47 and Highway 50, City Engineer Jonathan Zimmermann told commissioners. The “pretty dramatic changes” would place several businesses within the flood plain that are not currently.

The proposed changes could even impact the cost of the city’s planned $10.2 million Union Expressway project, which includes a realignment of Highway 47 and a new bridge over the river, Zimmermann said. The 2,000-foot bridge would span the river and floodplain.

“It could have a lot of impact on the community,” he said.

Zimmermann plans to take part in a commenting system about the changes to the federal and state emergency management agencies. Commenting is now open to flood plain managers.

“What I want to get across to you, is that even with us commenting, they might not change the mapping,” he said.

Parts of the area were heavily damaged by flooding in December 2015 and May 2017.

Properties located in a flood plain could be required to carry flood insurance, especially if they are receiving a loan from a bank, Zimmermann said.

“To the best of my knowledge it is not a mandatory program, in other words, if you self-fund nobody can make you buy it,” he said.

People who have a smaller percentage of their property in a flood plan have lower flood insurance costs than those fully in the plain, Zimmermann said.

“If you have a home that was maybe compliant now, or just had flood plain on the property, you might have a minor cost to your flood plain insurance,” he said. “But say your finished floor was three feet below that base flood elevation, it’s a totally different ballgame.”

After the meeting, Zimmermann said these flood studies are typically done after major floods, like the one in 2015. 

While the more sweeping study could take a couple years to approve, the study unanimously approved Monday by the Planning and Zoning Commission brings only “minor modifications” to the flood plain, Zimmermann said. 

The plan board recommended the study be approved. The board of aldermen will vote at future meeting to officially authorize the study. 

The plan is expected to go into effect in June.