How to find out if your home is in a floodplain

SIOUX CITY, Iowa (KCAU) — After the catastrophic levels of water seen a month ago, officials have updated their floodplain maps.

“Large parts of northwest Iowa have suffered record flooding and not just a little bit above the regular in some of these communities,” Jon Mills with FEMA said. “Water rose four or five feet above record flood stage. For some people, they’ve seen flooding before, but never like this.”

A floodplain is a flat area of land next to a river that is prone to flooding. Floodplain maps were created to help inform homeowners and the public about the potential risk of high water.

“Everyone works together on flood mapping,” Mills said. “It’s really a partnership with the state and FEMA and the local communities. So every flood map that’s in effect is adopted at the local level.”

“We have gauges all over the state, USGS gauges that are keeping track of how much water’s going down the rivers,” Chris Kahle, Floodplain Mapping Coordinator with the Iowa DNR, said. “So we consider those gauges when we’re doing the hydrology. This will be, you know, the outliers. The outliers are kind of like this doesn’t happen very often, so we’re not necessarily going to throw that in there. But it will make some of the earlier outliers now become not outliers.”

These maps use data from previous flooding incidents to show areas most likely to be impacted by rising water. However, it doesn’t account for the historic levels just seen in June.

“We never entirely know as much as we would like to predict with floodplains on what could happen with disasters,” Woodbury County Zoning Coordinator Dan Priestley said. “Floodplain management is about being proactive, trying to potentially mitigate things before they happen.”

“The concern is that if you flooded this time, chances are you will flood again in the future,” Mills said. “Being in a high risk zone means you have a 1% or greater chance of flooding every single year. It’s not just once every 100 years.”

To keep current, officials update the floodplain maps every ten years.

“The floodplain maps changed. So on July 17, 2024, our new maps came into effect that show the new areas of potential inundation in the event of the hundred year flood and the event of the 500 year flood,” Priestley said.

To find out if your home is in a floodplain, experts recommend reaching out to your city officials.

“I cannot emphasize enough for property owners to carefully look for and contact us if you’re unsure about the layout of the floodplain,” Preistley said. “We would be happy to point to the maps as far as if the property is in or out of the floodplain.”

To find out if your home is at risk of flooding according to these maps, click here .

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