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Archive for Monday, October 17, 2005

Maintaining levee system requires ‘constant vigilance’

October 17, 2005

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When Tom Orzulak asks you about the weather, it's not just idle chit-chat. He really would appreciate any insight you can give.

Such is the life of the man who oversees maintenance of Lawrence's river levee system. The 13-mile system along the Kansas River and the much smaller Mud Creek is designed to prevent flooding in North Lawrence. But the system only works well if the people who maintain it have a close eye on the skies.

There are 25 tubes throughout the levee that must be manually opened and closed during storms. The tubes, when open, allow stormwater to flow out of North Lawrence into the river. But if they are left open too long and the river rises too high, the tubes provide a way for Kansas River water to rush into North Lawrence.

"It is a real art trying to figure out how fast the river will rise," said Orzulak, who is the city's street division manager but also oversees a crew of five people responsible for levee maintenance. "We don't get much advance warning from anybody. It is basically a constant vigilance in watching the weather."

The entire levee system - which is designed to protect the area from a 500-year flood similar to the one in 1951 - recently passed its annual inspection by the U.S. Army Corps of Engineers. Corps officials inspect the integrity of the 30-year-old levee - made primarily of Kansas River sand and clay - and also ensure that the gate and tubing system is working correctly.

"It's a good levee. It does its job well," Orzulak said.

A balancing act

North Lawrence residents generally agree. Ted Boyle, president of the North Lawrence Improvement Assn., said the city did a good job of keeping the levee maintained, and that residents felt secure about the integrity of the levee.


Marcus and Kathy Bassett, of Topeka, ride their bikes on the Kansas River levee bike trail  below the Bowersock Dam on Friday.

Marcus and Kathy Bassett, of Topeka, ride their bikes on the Kansas River levee bike trail below the Bowersock Dam on Friday.

But Boyle said he would like to see some of the human element removed from the tube and gate system.

"In the 1993 flood, we felt like they didn't close them as soon as they should have," Boyle said. "We rely pretty heavily on them to close them at the right time."

Boyle said he would like for many of the tubes to be equipped with pumps instead of the manual gate valves. He said the pumps, as long as they don't suffer a mechanical failure, would ensure that river water would not back up into the pipes. That's because the pressure of the water pumped out of the pipes would be greater than the pressure created by the flowing river.

The levee system has four tubes that are equipped with pumps. Boyle, who is on a group studying North Lawrence drainage issues, said an engineering report being drafted will study the possibility of adding more pumps. But the solution likely would require hundreds of thousands of dollars.

Under the current system, water has backed up through the pipes into North Lawrence on occasion. Through the years, farmers from the area have occasionally lodged complaints that their fields received floodwaters through the pipes.

City leaders admit the current system is tricky. Chuck Soules, city director of public works, said crews do try to leave the gates open as long as possible because they want to let as much stormwater out of North Lawrence as possible.

"It is a balancing act," Soules said.

Watching other areas

And Orzulak said it's not as easy as people may think. That's because the Kansas River watershed is so large that rain events in an entirely different part of the state can cause the river to rise rapidly.

For example, the storms earlier this month that produced flooding in Rossville and other areas north of Lawrence only dropped three-quarters of an inch of rain in Lawrence, Orzulak said.

"But the river sure did go up here," Orzulak said.

Orzulak said his crews basically have to watch weather conditions as far west as Salina.

In addition to the opening and closing of the gates, Orzulak said the five-person crew - which splits its time between maintenance at the levy and the airport - does mowing, places rock to prevent erosion and repairs ruts created by animals or people on motorcycles or motorized vehicles.

The ruts can be a particular problem, Soules said, because a small rut can easily turn into a large rut when the river begins to flow rapidly. Soules said that's a prime reason why the city prohibits motorcycles, ATVs and other motorized vehicles on the levee.

Orzulak said his crew was proud of the recent high marks the levee system received because many people probably don't realize the work that is required to keep the Kansas River contained.

"Most of the work that happens on the levee is one of those things that just happens and no one blinks an eye about it," Orzulak said. "But if we were doing a bad job, they would know in a hurry."

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