Leaving Land Alone To Hold Floodwater West Of Houston

One effort aims to slow down floodwaters before they ever get to Houston.

By Dave FehlingJune 1, 2016 9:30 am| , ,

From Houston Public Media

Houston sprawls for miles, but we went to where that sprawl stops.

“I think if you’d listen for a minute, you don’t hear any cars,” says Mary Anne Piacentini as she stands near a pond on the Katy Prairie 45 miles west of downtown Houston.

“We protect over 20,000 acres right now,” says Piacentini, director of the Katy Prairie Conservancy.

Twenty thousand acres of farm and ranch land and restored wetlands are protected from housing and commercial development that’s creeping ever closer as Houston grows bigger. And last month when the big Tax Day Storm hit, much of the acreage flooded.

“I couldn’t get here that day,” says Wesley Newman, the prairie project’s conservation director. “This would all been underwater.”

These thousands of acres of prairie held back millions of gallons of rainwater that otherwise would have flowed eastward. A good part of it would have run into the Barker and Addicks reservoirs which still filled with record amounts of water from last month’s storm.

“We think that the Katy Prairie is critical. Will it do everything to stop flooding? No, but it will go a long way,” Piacentini says.

But will it? The experts say there’s no doubt prairies absorb or hold back a certain amount of rainfall, but when something like a foot and a half falls as it did here last month, do prairies matter?

Mike Talbott heads Harris County Flood Control has his doubts when such catastrophic rainstorms strike.

“You know, the whole idea of us paving over our prairies and our wetlands causes flooding. You know, Addicks and Barker reservoirs were built 80 years ago,” Talbott said.

Talbott  points out that decades ago, the Addicks and Barker reservoirs were built to hold the storm water coming from the Katy Prairie which back then was far larger than now because urban sprawl hadn’t yet happened. And when it rained on Tax Day?

“The hardest rainfall we had during the April event here was on the Katy Prairie and that water ran off and flooded the developed area,” Talbott says.

Piacentini, with the prairie conservancy, concedes the prairie won’t hold all the rain that falls on it.

“It’s probably true that some of the water does flow across the prairies to downtown. But the more prairie grasses that you have here, the more native vegetation, the more likely it is we’re going to slow that down. Even with 20 inches of rain, we did not lose all the rain within a day. The water was there for days,” Piacentini says.

None of this is to say the county doesn’t care about the prairie or what role it might play in flood reduction. In fact, Piacentini says the prairie conservancy has been working with the county for years on a proposal to build berm a few feet high and eight miles long to slow of prairie storm water as it heads to the Addicks and Barker reservoirs. But it’s still on the drawing board and under study.

“They’ve been waiting to present it to commissioners court to get approval for it,” Piacentini says.

Piacentini says maybe the Tax Day floods will add some urgency to such projects and increase interest in how a prairie might help keep a sprawling Houston a little drier.