Flood map

The impact that forthcoming floodplain maps covering Madison, Gallatin and Broadwater counties will have on the city of Three Forks really can’t be overstated.

“This one is a bigger magnitude than any map update Three Forks has ever had,” the city’s Floodplain Administrator Kelly Smith said.

On Jan. 6, the City of Three Forks held a virtual open house to allow landowners the opportunity to review newly released draft floodplain maps for their region. There they learned that in the Three Forks area, new draft maps add 164 acres to the 100-year floodplain — property that has a 1 percent annual chance of flooding. Only 12.4 acres were removed from the floodplain on draft maps.

Perhaps more significantly, 153.9 acres in the area have been added to the floodway — land on which no new development will be permitted — and only 2.8 acres removed. Under existing maps, none of the city lies in the floodway, so this represents a significant change.

“The west side of town becoming floodway is huge,” Smith said. “Structures in the floodway are definitely going to be impacted because they won’t be able to get permits or build or add to their properties.”

Improvements to existing buildings in the floodway will require a Floodplain Development permit. Additionally, owners of mortgaged structures in high-risk zones may be required to have flood insurance.

The Montana Department of Natural Resources and Conservation (DNRC) and the Federal Emergency Management Agency (FEMA) have been working on creating updated floodplain maps in the area since 2016.