Corps Follows Rigorous Schedule to Restore Missouri River Levee L-550
The rumble of heavy equipment resonates through the crisp, 30-degree air. Just south of the Iowa-Missouri border, this work site adjacent to the Missouri River is a whirlwind of activity. Construction has begun to repair two breaches along Missouri River Levee Unit L-550, southwest of Watson, Mo., in Atchison County.
At the upper L-550 breach, several dozers, scrappers and tractors push and smooth large piles of sand across an open expanse with water typically 8 feet deep along a setback levee alignment. A setback levee is built slightly behind an existing levee and reconnects the ends of an original flood control structure that was damaged.
“The cold is actually giving us better access to the job,” says Joe Nolan, a U.S. Army Corps of Engineers construction representative with the Omaha District, each word accented by a puff of crystals. “We could barely get back here with four-wheel drive (a few weeks ago).”
Nolan and his team keep tabs on the some 25 contractors (Weston Solutions Inc. is the primary contractor) during this construction project that is running seven-days-a-week during daylight hours. If you’re going to work on Nolan’s site, you’d better know how to operate in the environment safely and efficiently. He’s already sent more than one operator home who wasn’t pulling his or her weight because safety, whether that of the public or a contractor on a work site, is the number one priority of the U.S. Army Corps of Engineers.
With a setback levee that will be roughly 36-feet wide at the base and have some 5 feet of clay along its riverside face, there’s simply no room for error or poor judgment. With funding made available recently through a nationwide disaster relief bill, the repairs being done at L-550 and the Missouri River Levee Unit L-575 to the north near the town of Hamburg will return the levees to their originally designed level of flood risk reduction. Both projects are anticipated to be completed by the start of next year’s runoff season.
The levee reduces the level of risk for flooding for those living and operating in the flood plain behind the levee, but it doesn’t remove the risk entirely. No structure could eliminate the risk.
The entire alignment of the setback levee is marked by a series of yellow stakes for the landward toe and blue stakes for the riverside toe. The base of the setback levee, including the portions underwater, is formed from compacted, heavy sand. Atop that sand will be a large layer of clay – it will form much of the levee’s visible bulk.
“Clay has a high plasticity that is resistant to change,” said Tim Gouger, the project manager for the Corps on repairs at both Missouri River Levee Units L-575 and L-550. “Water getting through or under your levee is your enemy. But clay swells and gets stronger when it gets wet.”
To get the clay necessary for the L-550 setback, the Corps and contractors will look to a combination of nearby lands as well as the portions of L-550 that protrude beyond the setback alignment.
“We’ll use the existing levee materials to the extent that we can,” Gouger says.
The setback levee will help reduce the flood risk to the villages of Watson and Phelps City as well as agricultural land and some 274 structures. Also, State Highway 136 and Interstate 29 run near the levee. Those roads are lifelines to communities in the area, including Rockport, Mo.
For local levee board vice president Max Peeler, the work can come none-too-soon. “Our county depends on Highway 136 and the taxes it helps to bring into the city of Rockport and the surrounding area,” Peeler says. “If we don’t get that tax, it about breaks Rockport. It’s affected a lot of people’s lives.”
Leroy Bow, a farmer in the Rockport region, agrees. He notes that with federal resources becoming scarcer, every decision made by the Corps and federal government has to be purposeful. “My big thing is we’re farmers – we live off the land. If we kill our land, we can’t survive,” Bow says. “We need to find a happy medium with all eight of the purposes (authorized by Congress). There’s a place where everybody can survive.”
With each levee project along the Missouri River, there are several groups who bring valuable assets to the table. “It requires collaboration among the Corps, contractors and sponsors to make this work – it’s emergency execution,” Gouger says, noting that typical civil works engineering projects take substantially longer to complete.
To monitor the progress at L-550 and other levees in the Omaha District, visit www.nwo.usace.army.mil.
Original construction on Levee L-550 began and March 26, 1948, and was completed Oct. 15, 1951
The levee sponsor is Atchison County Levee District.