Flood mitigation work at Riverfront Crossings District gets yearlong extension

IOWA CITY - The city has about another year to finish one of its flood mitigation projects left over from the flood of 2008, after the city found mercury contamination in the area.

The Iowa City Council on Tuesday night approved 6-0 a timeline extension, already approved by the state Flood Mitigation Board, for 13 extra months to complete its project at the old North Wastewater Treatment Plant. Council member Kingsley Botchway II was not present.

The city is required by the board to establish a wetland on the area where the plant was demolished and stabilize stream banks on Ralston Creek by Jan. 31, 2018. The wetlands area and a park are planned for the area where Ralston Creek feeds into the Iowa River - north of Highway 6 and south of Kirkwood Avenue.

The city needed the timeline extension after it discovered equipment from 1934 at the wastewater plant had leaked mercury on the site during the demolition, according to a memo the city sent to the board. The mercury cleanup and abatement process cost about $2.4 million.

Geoff Fruin, interim city manager, said while the cleanup took longer than the city anticipated, the mercury issue would not be dangerous for the wetland area or park.

The mercury has been removed, 'and it's not a concern anymore,” Fruin said.

The board paid the city almost $8.5 million in tax increment funding for the removal of the plant and the flood mitigation project, planned in hopes of preventing future flooding. The wetland is set to be 5 acres and should filter stormwater before it enters the creek, according to the memo.

The city hasn't heard concerns from any of the area's developers about the delay, Fruin said. He said the city has only heard excitement about the fact the city is working toward the park, which will make up the Riverfront Crossings District along with the wetlands and developments.

Fruin said that while the work on the wetland and creek needs to be finished before the new January deadline, the construction of a park on the land is not required to be done. He said once flood mitigation is completed, the city will look into paths, shelters and play structures to make it a more typical park.

Fruin said in the next month, city staff plans to present a contract for design work and recommendations for the flood mitigation work. The wetland and creek bank work are scheduled to begin in the spring. Since the 2008 flood, Iowa City consolidated the North Wastewater Treatment Plant services with the South Wastewater Treatment plant. This project is the most expensive flood recovery project that Iowa City faced, totaling $63.4 million.