Iowa City, Iowa was among the hardest hit communities from the 2008 Iowa River floods. Extensive flooding along the riverfront, including inundation of a major wastewater treatment plant located along the river, prompted the community to take action. Rather than restoring the vulnerable North Wastewater Treatment Plant, Iowa City decided to decommission the plant and expand service at a facility located outside the floodplain. The plant had an average daily treatment of 9.7 million gallons with a design capacity of 24.2 million gallons per day. Although it did not quantify future climate risks explicitly, Iowa City consciously sought means to reduce the vulnerability of its wastewater services to future extreme storm events, which are projected to increase in the Midwest according to the 2014 National Climate Assessment.
The process to decommission, demolish and expand wastewater treatment services elsewhere is projected to cost $63 million. By decommissioning the vulnerable wastewater treatment plant and converting the surrounding area into a public greenspace, the city has adapted to reduce the threat and impact of future extreme storm events.
Iowa City Public Works identified its wastewater treatment facilities as vulnerable to future extreme storm events.The City asked for technical assistance from the U.S. Environmental Protection Agency to develop an overarching Riverfront Master Plan, including a Treatment Plant Restoration Plan.
Iowa City reduced current and future vulnerability when it consolidated wastewater treatment service in a low-risk area outside of the floodplain. The $63 million project involved decommissioning a vulnerable facility, thereby reducing future flood risk and the potential for untreated sewage releases.
By adopting an approach that used both gray and green infrastructure, the City yields multiple benefits through less vulnerable wastewater services, improved stormwater management and creation of a new public space for recreational opportunities.
Iowa City secured outside funding. The project was partially federally funded - $22 million from the Economic Development Administration and $13 million from Community Development Block Grants Supplemental Disaster Funds.
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Iowa City, Iowa decided to move their facility away from danger.