Cedar Rapids to try out removable flood walls

CEDAR RAPIDS — Unlike a flood, flood protection won't come all at once, city officials have said.

Case in point: The City Council today will vote to seek bids from companies that can provide one piece of the coming flood protection system — a flood wall system of removable or 'demountable' panels.

Removable flood walls will be located through the downtown and across the Cedar River at Kingston Village and Czech Village, according to the city's current plans.

Dave Elgin, the city's public works director, on Monday said the city's initial foray into removable walls will consist of a demonstration project to place removable panels at the McGrath Amphitheatre between already existing columns designed to be part of a removable wall system.

Elgin said the city expects that the demonstration project, which is estimated to cost about $250,000, will show the city which system of removable walls might be the most cost-effective to purchase and be the most efficient to install.

He said the city is aware of three manufacturers that operate in the United States or Canada and have been approved by the Army Corps of Engineers. The bid process may identify more manufacturers, he said.

Elgin and other city leaders traveled to Nashville, Tenn., to look at its removable wall system, and Elgin said one attractive feature of Nashville's system was the ease of installation.

Final design of the city's flood protection system is yet to come, but the preliminary design always has envisioned removable flood walls through the downtown rather than permanent, towering flood walls, Elgin said.

'If you build a 12-to-14- or 15-foot-high wall, those people who used to be able to see the river are going to be behind the wall,' he said. 'Even from Day 1, because those kind of extreme floods (such as in 2008) are relatively infrequent, the thought was to have removable or demountable walls, as the Army Corps of Engineers refers to them.'

Elgin said the preliminary plans call for about 4,000 feet of removable walls on the east side of the river and 1,100 on the west side, with an additional 2,000 feet of removable systems on both sides of the river that will serve as gates at the bridges.

A series of permanent concrete columns — the ones at the McGrath Amphitheatre are an example of those — will be erected, between which the removable panels will be inserted at the time of a flood.

Elgin said the city estimates that it will have 72 hours to get the removable walls in place once an extreme flood is projected. The city can install walls to protect to a certain level and then go back and raise the walls higher if the river continues to climb, he said.

Public hearings

In a second matter related to the city's flood protection plans, the City Council today also will set public hearings to spell out its plan to incorporate a flood wall and pump-station reservoir into the construction of CRST International Inc.'s new 11-story headquarters on the riverfront in the 200 block of First Street SE.

The city and CRST have entered into a development agreement, which spells out that CRST will incorporate the flood protection elements into its construction and that the city will purchase the elements.

The estimated cost of the flood protection wall and pump-station reservoir at the CRST building is $3.95 million.

The city has put the estimated total cost of the both-sides-of-the-river system of levees, flood walls and removable flood walls at $570 million. The figure consists of:

•$117 million in federal funds already spent for property buyouts and other flood-recovery projects

•$264 million in state flood-mitigation funds

•$78 million in expected additional federal funds

•About $110 million in local funds.

In its request for bids on removable flood walls, the city will ask potential vendors to meet an April 17, 2015, deadline.

The city will open bids on Sept. 10.