Iowa City, Coralville undertaking flood projects at different paces

CORALVILLE – During the 2008 flood, Coralville officials went around by boat and even plane surveying the water with an eye toward the future.

City Administrator Kelly Hayworth and City Engineer Dan Holderness used a fire department boat to observe various places to see what was flooding and when as Coralville Lake, the Iowa River and Clear Creek continued to rise.

Scott Larson, the assistant city engineer, took to the air to shoot photographs.

And the city hired a consultant to take measurements of the flood.

All of this was done to prepare for post-flood work. And now, five years later, Coralville is nearly finished with most of its flood-related projects.

'With that information, we were able to turn around and make plans for how to protect ourselves in the future,' Hayworth said.

The city lists five flood-protection projects, some of them with multiple components, costing $64.2 million.

The biggest is $37.1 million spent on the First Avenue corridor between Interstate 80 and Second Street. The southern end of that is where the Iowa River and Clear Creek converge, and the area was under several feet of water in 2008. That was problematic for more than just Coralville residents because First Avenue and Second Street is the busiest intersection in Johnson County with lot of the traffic going to University of Iowa Hospitals and Clinics.

The work, mostly completed in 2011, included building a higher and longer First Avenue bridge over the creek, allowing 100-year-flood levels to pass underneath. First Avenue also was widened and storm water pump stations, storm sewer upgrades, berms and flood walls were installed along the Iowa River.

Another major project, at $11.7 million, is the elevation of the Cedar Rapids and Iowa City Railroad from near the Iowa River Power Restaurant on First Avenue to Rocky Shore Drive to help keep the river at bay. Work got underway last fall and is to finish next year.

Other measures include more pump stations, backflow prevention and berms and floodwalls along Clear Creek and Biscuit and an area where redevelopment is occurring.

The city also has three projects totaling $8.8 million it says are needed to complete the flood-protection system, but there is no funding for those at this time.

Holderness said all of the projects offer protection at least up to 100-year-flood levels plus one foot. Removable walls that can be installed as needed will extend those up to 500-year levels, which would be comparable with the flooding seen in 2008.

'It's a significant improvement over where we were in '08,' Holderness said.

In Iowa City, construction on most of the major flood-related projects is still to come. Its plans are grander than in Coralville, with 15 projects costing about $150 million proposed.

Iowa City also has seen its plans altered. The City Council last fall chose not to build a levee along Taft Speedway in the face of intense criticism from the people who live in the nine homes still on the street who would have been between the levee and the Iowa River.

That decision was condemned by the residents of the 92-unit Idyllwild condominium complex the levee was meant to protect.

The city also killed a levee proposed for the east side of the Iowa River on the south side of town after costs spiraled out of control.

The city's top two flood projects are moving ahead, though. One is the largest public works project in Iowa City history: the $54.8 million relocation of the north wastewater treatment plant, which flooded in 2008, to the south plant. Construction is underway and is to finish next year.

The other priority is what the city is calling the Gateway Project, which is the elevation of Dubuque Street and Park Road bridge by City Park on a main entryway into town. A portion of Dubuque Street frequently floods, and the bridge acted like a dam in 2008 with 52 tons of debris removed from its upstream side, said Rick Fosse, Iowa City's public works director.

The $40 million project is in the preliminary design phase, with construction slated for 2015-16.

Other projects include a new animal shelter, a levee on the west side of the river on the south side of town and the CRANDIC project with Coralville.

Fosse pointed to that last project, which the University of Iowa also is involved in, as an example of the government cooperation.

Some people have said they don't believe the cities and the UI are taking into consideration how a project can affect water flow and levels up and down stream.

But Fosse said Iowa City, UI and Coralville are all aware of what the others are doing and work off a single hydraulic model to predict the effects of the various projects.

Much of the cost for the projects in both cities is being covered by the federal and state governments. A voter-approved local-option sales tax is estimated to generate $32.8 million for Iowa City's wastewater plant and Gateway projects over its four-year life.