New flood maps show fewer Pocatello homes at risk
The City of Pocatello hosted a flood risk open house on Monday to outline the preliminary changes made to the city’s floodplain maps. While many feared the updated maps would put their homes in at-risk areas, it didn’t add a single one and actually removed many homes and technology is to thank.
“This is actually a good thing for the majority of homeowners,” Pocatello Public Works Director Jeff Mansfield explained. “A lot of the homes that were in the floodplain are now no longer in the floodplain.”
Mansfield said the entire reason the open house was held was to determine the risks of a one percent flood, which is the chance a hundred-year flood has of occurring each year.
With the newer technology, “they were able to determine that less houses have a potential for that one percent flood.”
One of the ways the city determined the risks was through the use of LIDAR data, a method of surveying that uses lasers to create 3-D models of targeted areas.
It’s something that Idaho State University GIS director Keithth Weber is quite the expert on.
“We can see things with the imagery, and with this data, that you just couldn’t see before,” Weber explained. “You can resolve things. Stream channels, even channels of streams that may have been dried up for some time, suddenly are revealed on this level of imagery.”
The advances in resolution have allowed for much higher quality data. Looking at a map with newer LIDAR technology, “you can see the roads, here, here, here. And if we now turn that off, it kind of disappears,” Weber said.
The higher resolution of the new imaging allows researchers like Weber to get better data on things like erosion, landslides, avalanches, among other things.
With data of this quality, people like Weber can provide better information to city and county officials with more confidence.
“So then we’re gonna have better-informed decisions, on the part of emergency managers and coordinators and Bannock County, or any of the counties across Idaho,” Weber said. “Better information being given to the cities and ultimately, just better decisions for the people who are living here in Idaho.”
But it’s important to remember these flood maps are just estimations.
“That doesn’t mean that you won’t get flooded if you’re outside of that area,” Mansfield said. “And so really, it’s just kind of a tool to help us predict where those people are that need insurance.”
Mansfield said that those who may have flood insurance and no longer live in a floodplain area will be able to make a decision as to whether or not they keep the coverage.
