Expect removable flood walls, Cedar Rapids city officials tell Linn supervisors

Dec. 16--Linn County's supervisors raised three issues with Cedar Rapids city officials on Monday about the city's coming flood protection system on both sides of the Cedar River:

Supervisor Lu Barron asked the city to keep aesthetics in mind and don't just build "concrete flood walls."

Supervisor John Harris said he wanted to see a new hydrologic analysis to make sure that flood protection in Cedar Rapids doesn't raise flood levels upstream in Palo.

Supervisor Brent Oleson wondered if the city could use any of the $264 million in the city's new state grant to protect May's Island, home to the county courthouse and jail and the city's Veterans Memorial Building.

Dave Elgin, Cedar Rapids' public works director and city engineer, told Barron that the city's flood protection plan is neither an economy model or a Cadillac, but a plan that has made room for more attractive, more costly removable flood walls than the Army Corps of Engineers has included in the Corps' partial piece of the city's flood protection plan.

City and county officials went to Nashville a week ago to see how that city has used removable flood walls to protect itself, and Elgin said the trip convinced the city that the latest technology in removable flood walls has created walls that are less expensive, simpler and more easy to install.

Elgin said the city now thinks it will be able to expand the use of removable flood walls beyond what it initially had thought.

The city has been looking at removable walls for downtown, across the river at Kingston Village and Czech Village.

Elgin said the Nashville trip showed how buildings can be built to incorporate removable walls into their first floors, which he said may happen with the parking ramp planned between First Avenue West and Interstate 380 to provide parking for the proposed Cedar Crossing Casino.

Elgin told Supervisor Harris that the Army Corps has conducted a preliminary analysis of the impact of Cedar Rapids flood protection on the Cedar River's hydrology.

The analysis, Elgin said, showed that the impacts upstream and downstream are negligible in the event of a 100-year flood, and would raise the river less than a foot at Palo in a repeat of the 2008 record flood. Elgin said the impact would be less because the Corps' preliminary analysis looked at a flood protection system with flood walls next to the river. However, the city's plan calls for greenway areas, in part, that will let the river spread out and so lessen the impact upstream, he said.

The city's application to the Iowa Flood Mitigation Board, which earlier this month awarded the city a $264-million grant over 20 years for flood protection , calls for the system to be built in several phases over 20 years.

The application states that the city wanted to leave the option open to provide flood protection on May's Island, and Joe O'Hern, the city's executive administrator for development services, told Supervisor Oleson that the state funds come with flexibility to use money for May's Island if other parts of the flood protection system cost less or if May's Island becomes more of a priority.

After Monday's meeting, Oleson said the county likely will need to find additional funding to help with May's Island if it decided that flood insurance wasn't sufficient to protect the county buildings on the island. The buildings were renovated after the 2008 in a way to lessen any future damage.

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