Big project aims to reduce flooding

By Travis Coltrain

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Officials unveiled a $2 billion project aimed at reducing floods, showing it off to the media for the first time Wednesday.

The University of Iowa IIHR-Hydroscience & Engineering revealed its completed smaller-scale model of a sewer system that will soon be built in St. Louis.

The model was only 1/16 the size of the actual model, which is estimated to handle upwards of 4,420 million gallons, said Troy Lyons, the IIHR director of engineering services.

“The purpose of our model is to study and evaluate the hydraulics of a system that’s being built and designed for the city of St. Louis to intercept excess storm water,” Lyons said.

The current system in St. Louis has flaws, he said. Currently, the system has a tipping point — despite its large figure, flooding is still possible in storms.

Jacob Odgaard, an IIHR research engineer, compared older systems to cathedrals, saying, “This type of system comes in very handy; it’s a good tool for the cities, it is very elegant because it doesn’t take up much space.”

Space is very hard to come by in metropolitan areas. Odgaard said with climate change affecting the weather, the best place to store water is underneath the city in tunnels instead of letting it flood onto the roads.

The new system is designed differently, allowing excessive water to be intercepted and transferred into an underground storage tank, instead of letting it continue to the river, Lyons said.

There are certain aspects to how the water is flowing and the geometry of the pipes that specifically allows for this application, he said.

Then, after the storm has passed, that water is pumped out, treated, and discharged.

“Storm water is a big problem, and that’s why the underground tunnels become so convenient,” Odgaard said. “Although they are expensive to build, they will prevent flooding.”

UI senior Kory Miller, an assistant designer at IIHR, has worked on the project for months now.

“I helped design it on a computer program, each part of the structure holding it up I drew so each person in the shop knew what dimensions each part needed to be,” he said.

He said he believes the vortex drop shaft is the most impressive part of the project. Its purpose is to lower the water deeper into the ground while also regulating and controlling the flow of water and air inside the system.

The vortex drop shaft is estimated to be the largest of its kind, once built to scale, Lyons said.

The vortex is used to prevent pressure buildup in the lower pipe from air coming in. Water spins around with the air in the middle, which will prevent pipes from breaking and manhole covers from going flying.

“We’ve seen a lot of success all over now; it goes by word of mouth from one city to the next,” Odgaard said.

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