A certain phrase rolls nicely off the tongue, and thus it has become part of our language: “The 100-year flood.”
As soon as those words are uttered, though, a public official or insurance specialist jumps in with a correction.
“No, that designation doesn’t really mean that you’re in a spot that is likely to flood once in 100 years,” they’ll say.
“What it means is that you have a 1 percent chance of a major flood in any single given year.”
Fair enough, but…
Perhaps some new math may be required for a significant chunk of Riley County — including the west side of Manhattan.
Wildcat Creek and its tributaries have produced serious flooding three times in the past seven years — in 2007, 2010 and 2011.
Experts insist that all the factors leading to those events appear to be getting more ominous, so it would seem the risk has become far greater than 1 percent per year.
“I’m not the guy doing the math and putting a figure on it,” said Manhattan senior planner Chad Bunger, “but the probability has become high enough to be really scary.
“And besides the possibility that Wildcat Creek could flood again anytime, this is a completely different animal than, say, a flood where the Big Blue (River) goes over its banks. That’s a terrible event, but we can see it coming and there’s time to plan, to get out of the way.
“Wildcat Creek floods in a hurry, with water rushing down at us from the northwest, and under certain conditions, it doesn’t even take much rain to make it happen.
“In 2011, a whole lot of people (estimated to be around 300) had to be evacuated in a big hurry. The whole event, sudden flooding over a large area and then water receding, only took about eight hours.
“That’s a frightening situation.”
The Wildcat Creek watershed is fairly large — about 100 square miles, roughly an oval-shaped area that extends from the creek’s headwaters near Leonardville down to the point where it empties into the Kansas River.
The creek flows southwest past the town of Riley and through a portion of Fort Riley before entering Manhattan from the west. Once in town, most of the way it winds along between Anderson Drive and Fort Riley Boulevard.
Wildcat also is fed by several tributaries along the route, adding to the amount of water gathering during the trip.
“The reality is that we’re the drain at the bottom of the tub,” Bunger said. “The water builds up in volume and speed by the time it gets to us, which isn’t good news at all.”
Several Manhattan neighborhoods are almost certain to flood whenever Wildcat Creek rises again – Garden Way (with several apartment complexes and a seniors’ residence center), Redbud Estates mobile home park, the areas south of Anderson around Village Drive, Deer Run, and of course, some low-lying non-residential spaces like Anneberg Park.
“(The city) has done just about everything available to us,” Bunger said. “We only represent 10 percent of the Wildcat Creek watershed. Unfortunately, we’re sitting down here where it’s going to flood.”
One troubling issue is that there isn’t really any consensus concerning how Wildcat Creek has become such a danger, nor how to remedy the situation.
After the flood in June of 2011, it became obvious that a problem existed and that somebody needed to address it.
So a body called the Wildcat Creek Watershed Working Group was convened — comprising representatives from private industry, the city of Manhattan, Riley County, the U.S. Army Corps of Engineers and the Kansas Hazard Mitigation Team.
Getting all interested parties together seemed like the right approach. Unfortunately, not everyone had the same ideas — either about the cause of the floods, or what to do about them.
For instance, Riley County floodplain coordinator Steve Higgins believes that the issue is mostly a fluke of nature; specifically, changing climate conditions that seem to be racing ahead of efforts to halt the troubles.
Higgins isn’t suggesting that efforts to ease the problems should be abandoned, but he feels that he’s fighting an impossible foe.
“What’s happened in the flood years has been down to large amounts of rainfall that were unprecedented,” he said. “We’re prepared for rain here, obviously, but nobody expects 8-10 inches in less than an hour.
“It’s just too much. Our bridges and other structures just aren’t built to handle that kind of force.
“This may be something we need to expect. (State climatologist) Mary Knapp says that the change in overall climate may lead to more and more storms of these levels — or worse. It’s going to keep happening.”
Whether or not that prediction of routine violent weather turns out to be true, everyone in the working group had some thoughts about how things have become so dangerous, and what can be done to lessen the damage.
“There’s no secret about it,” said contractor Russ Weisbender, who lives in the flood zone at the west edge of town. “Continual development upstream has stripped away vegetation and other natural elements that used to absorb some of the water.
“Instead of going through trees and over softer ground that might soak up water, now it’s just gushing off roofs and streets built above the creek.
“Several of us who were involved in the working group tried to tell the city and county to curb development — instead of building all these things along Scenic Drive and other places.
“Honestly, though, I felt like nobody was listening to us, because we don’t have degrees in hydrology or whatever. But you don’t have to be a hydrologist to use some common sense and see where all this extra water is coming from.”
County commissioner Ron Wells, who also lives in a high-risk area on Anderson west of Seth Child Road, echoed Weisbender’s complaint about too much development in the wrong places — and complained that so-called flood experts weren’t facing up to reality.
“We put markers on trees to see where the high-water marks would be,” Wells said.
“And it turned out we were getting flooded in places their computers said wouldn’t flood.
“Sometimes you’ve got to stop putting total faith in models and actually go take a look at what’s happening, and where this water is coming from.
“There’s no question that the situation is getting worse. We’ve got a bridge on our property, and in 2007, the water was considerably under it. In 2010, it was almost up to the level of the bridge, and the next year it actually went right on over it.
“Nature has something to do with it, we know that, but we’re making things worse with man-made decisions — or because in some circumstances, we’re not doing anything about it.”
Weisbender has suggested that a wetlands area be created at Fort Riley, thus absorbing a significant amount of water as it comes downstream.
Wells agreed, and chided the Army for its lack of cooperation.
“(The working group) didn’t accomplish a thing, in my opinion,” he said. “It’s going to flood again.
“So why can’t the Corps of Engineers get involved and help? Wetlands or a detention area on Fort Riley land would be a great help. There are plenty of troops with enough idle time to do that.”
Wells also admitted to frustration that nothing seemed to get done with farmers and other landowners upstream, arguing that anything to cut down the amount of water that eventually gushes into Manhattan would be useful.
“There are five creeks flowing into Wildcat,” he said. “We’ve talked and talked about it, but nobody seems to have the authority to do anything.”
Another frustration, at least for Higgins, is that the creek’s path basically parallels that of an old railroad line, and the track channels which could absorb some water are choked up with debris.
“They need to be unplugged,” he said, “but most of that property is on private land, and you can’t force people to do that.”
At the end of the day, though, Higgins believes that – whatever mitigation can be accomplished – they could be fighting a losing battle.
“To be honest,” he said, “I think this is Mother Nature proving a point.”
That notion doesn’t sit well with Wells, who is quite certain human beings have been giving nature plenty of help in creating the danger posed by Wildcat Creek.
“It’s just silly,” Wells said. “We’ve allowed development in the wrong places, and eventually the taxpayers may be on the hook for it if we pay $14 million to buy 121 properties — just because they’re going to keep on getting flooded.”
Weisbender agreed with Higgins’ view that things may get worse, but not for the same reason.
“Every time we build another house or apartment complex above the creek, we add to the runoff,” he said.
“We shouldn’t act surprised when more water comes rushing into town. What’s happened is terrible, just terrible.”