Flooding threat poses vexing problem to Nall Hills neighborhood, Overland Park engineers

An engineering study recommended the eventual demolition of dozens of homes along the Indian Creek channel in the Nall Hills neighborhood.

For residents along Indian Creek in the Nall Hills neighborhood, the beginning of spring rainy season this year will bring a sense of unease. Will this be a normal year, or will it bring a repeat of 2017, when two torrential storms caused the creek to overflow, flooding homes and streets?

The neighborhood asked Overland Park city engineers for help that year. This year they got good news and bad news.

The “good” news: A storm water management project that would solve the problem is too expensive for either the city or county to take on, meaning it won’t be necessary to bulldoze 40 homes and one business for the construction. The bad news: There’s little else the city can do but refer homeowners to a Federal Emergency Management Agency website on steps they can take to protect their property.

One of the graphics from the engineering study report, showing 40 homes in the Indian Creek floodplain that could be bought out and razed under one recommendation.

Overland Park delivered that assessment last month to disappointed residents from 99th Street to 102nd Street between Lamar and Nall Avenues. “They were hoping we just had a straightforward solution,” to deepen and widen the channel and bridges, said Lorraine Basalo, assistant city engineer.

But nothing about the problem has been straightforward.

The neighborhood of ranches and occasional two-story homes was built in the early 1960s, before many flood plain maps were available, Basalo said. Homes in the southern part of the flood area lie closer to Indian Creek than they would if they’d been built today. There’s only about a one percent probability of a flood there in any given year, but when one does happen, it’s often more severe, sometimes reaching the homes. The problem is exacerbated by bridges at Lamar and Nall that don’t allow enough water to pass in an extreme rain.

The northern part involves the creek’s tributary. The channel there is not built to carry larger amounts of water in heavy rains, she said. But although the flood probability there is higher – between 4 to 10 percent in a given year – it’s less likely to cause damage to homes.

The city started an engineering study after being contacted by neighborhood residents and meeting with them in the fall of 2017. Officials then worked out three alternatives for each area, which they presented last month.

In the southern area, where homes were lowest and most vulnerable, the city said a full buyout was the best choice to solve the problem. That would entail the demolition of 40 homes and one commercial property that were either in direct danger of flooding or would be in the way of construction. It would also realign the road. All told it would cost $17.3 million.

On the tributary, the recommended solution was less drastic. It would involve channel and culvert improvements and no home buyouts. That alternative would cost $6.6 million.

Those recommendations did not make everyone happy. Mark Read’s home, on Lamar Ave., was not flooded during the storms. Still, he wondered why they city recommended razing homes when, by his estimation, widening the channel beneath the bridges would accomplish the same thing. Most of the homes that would be demolished never see floodwaters, he said.

He got out measuring equipment and figured that water backing up at the bridges was the real culprit. Most of the damage to homes happened near the bridges, he said.

“I don’t want to be perceived as that guy who’s against everything and doesn’t want the city to have nice things,” he said. “But I am a person who wants a firm foundation of understanding what the problem is you’re trying to address and the solution that actively addresses it.”

But it’s not that simple, said Basalo. Changing the bridges would not take care of all the water in a major storm. “Even if we took those bridges out there would still be extensive flooding. If it were that straightforward we would love for that to be the solution. But it’s not.”

Not only would the bridge work not be enough to solve the flooding, but it could cause flooding issues downstream, she said. To do that would mean spending on a project that would do no good and perhaps make things worse.

Although the engineer recommendations are the two least expensive, they are still likely too rich for Overland Park’s blood, Basalo said. The city typically spends about $3.5 million on storm water projects per year. At a combined cost of $23.9 million, Nall Hills would take up the entire budget for the city for more than six years.

Johnson County assists in some storm water projects, but their yearly budget is $12 million to $15 million, Basalo said. In fact the Nall Hills proposals were passed along to the county, which gives each project a priority. Nall Hills ranked dead last.

Which means that the neighborhood is stuck. Streamway improvement there is not on anyone’s five-year plan. But as extreme weather is expected to persist, residents will still have to put up with the occasional high water. The city referred them to a link on the FEMA website with advice on how to protect their property.

But Read said the city should do something. “Instead of searching for perfection for a project that will never be done, can we look at the homes that do have flooding and try to come up with a solution for them?” he said.

“I find it cruelly ironic that the people in the greatest need of help who can most easily demonstrate they have these horrific episodes of flooding are least likely to have any kind of benefit come from it.”