Army Corps prepares to take on huge Red River diversion projectby Dan Gunderson, Minnesota Public Radio
Moorhead, Minn. — Fargo-Moorhead officials are lobbying hard for federal funding for a Red River diversion project. The goal is to get the $1.4 billion project included in the federal budget next year.
If the diversion is funded, it will be one of the largest, most complex projects built by the Army Corps of Engineers in this region.
The Red River flows right between the cities of Fargo, N.D. and Moorhead, Minn. So to prevent flooding, the Corps of Engineers proposes a big ditch to divert water from the river and route it around the cities during a flood.
The diversion will be 36 miles long. It will be 30 feet deep -- the height of a three-story building. The channel will be up to 600 feet wide at the top.
Project manager Aaron Snyder says the only comparable project in this region is the system of locks and dams on the Mississippi river.
The first challenge will be moving dirt -- a lot of dirt.
"It's in excess of about 60 million cubic yards," said Snyder. "The average dump truck has 12 or 14 yards, so you can see how many millions of dump truck loads it would take. It's just a massive, massive amount of earth to be moving."
It's more than four million dump truck loads of dirt. Most of the dirt will be piled in what are called spoil banks, hundreds of feet wide on each side of the channel.
The diversion will cross several rail lines and roads, which means lots of bridges need to be built.
"There's four railroad bridges, there's going to be 18 highway bridges," said Snyder. "Those are kind of traditional and easy."
It won't be as easy to build crossings over five rivers, all tributaries that flow into the Red River.
Snyder says two of those river crossings will use concrete aqueducts to separate the river from the diversion.
"The diversion channel actually flows underneath the existing river system," Snyder said. "Those are definitely unique, and I don't know of any examples of those in the nation -- or even in the world, for that matter."
Snyder says the aqueducts will be an engineering challenge. Engineers will develop computer models to test the aqueduct design.
"And then we'll take it a step further and develop a physical model, where we have a scale model and run water through that and be able to monitor how that functions," he said.
To divert water from the Red River during a flood, gates will be lowered into the river. The structure will look a lot like a bridge crossing the river. But when water is high, 50-foot-wide gates will be lowered, partially blocking the river and forcing water into the nearby diversion channel.
Each of the gates and the aqueducts will be built alongside the rivers. When they are complete, the river will be rerouted to flow through or over the concrete structure.
The Corps of Engineers estimates the project will take eight and a half years to build. It's not clear how many construction jobs would be created by the diversion.
But Snyder says it's clear the St. Paul Corps of Engineers office doesn't have enough staff to design and build the massive project.
"We're going to have to look for regional resources, meaning other districts within the Corps. In particular, Rock Island, St. Louis, Memphis, Vicksburg and New Orleans. Those districts will all help us on this project," he said.
Of course, not a shovelful of dirt will be moved unless the $1.4 billion project gets federal funding. That decision could happen by early next year. If Congress and the president approve the project, construction will start in 2012.
- Morning Edition, 07/12/2010, 8:35 a.m.