Floodwaters made highways and hundreds of smaller roads impassable and wreaked havoc on road base material. Photo: Iowa DOT
Like most states nestled at the confluence for two rivers, Iowa was originally a military outpost. Which is fitting, because infrastructure managers have been battling the swollen tributaries of the Mississippi River—in Iowa's case, the Des Moines and Raccoon rivers—in the worst series of storms since 1993.
The Buckeye State was the worst hit of nine Midwestern states. Since May 25, when an F5-level tornado hit the northeastern part of the state, the Federal Emergency Management Agency (FEMA) has declared 83 of Iowa's 99 counties disaster areas and awarded $7.9 million to 77 public projects, most related to infrastructure.
In June, the state Department of Natural Resources issued a 90-day suspension of what would otherwise be violations—bypassing treatment units, discharging directly from sewers and pumping stations, and exceeding permit limits—to help wastewater treatment plants cope with overwhelming volumes. Even at maximum capacity of 87 mgd, Cedar Rapids' wastewater treatment plant was completely incapacitated. Divers were called in to get a pumping station working a gain, and short-term repairs that include baking motors to remove moisture are estimated at $4 to $5 million.
Despite expanding hours from 7 a.m. to 7 p.m. seven days of the week, traffic into both landfills of the Cedar Rapids Linn County Solid Waste Agency in Marion backed up as residents and contractors lined up to take advantage of a 6% drop in tipping fees to $32.90/ton.
After Texas, Iowa has more bridges —$25,000 counting city, county, and state structures—than any other state. The state DOT received reports from at least five communities that railroad bridges were entirely or partially swept away, but didn't lose any of its 2,100 bridges and closed just one when an Internet-based monitoring system alert-ed engineers.
The department's kept tabs on 180 scour-critical bridges with a Web-based system deployed in 2006 for approximately $100,000. Data from U.S. Geological Survey streamflow-gauging stations and National Weather Service rainfall reports are incorporated into structure-monitoring software developed by US Engineering Solutions.
“It costs about $56,000 annually in license and user fees, but it's a much better use of public funds,” says DOT Preliminary Bridge Engineer Dave Claman, PE. “In the past, people had to be sent into the field to check every single bridge. Here, maintenance employees only go to the bridge when alerted.”