Following the floods of 2010, the City Council established a goal of mitigating the impact of future flooding in Ames. A comprehensive Flood Mitigation Study was completed in late 2013 that considered many possible mitigation alternatives across a wide range of factors, including the degree of reduction of flood water elevation, estimated annual damage reduction, construction costs, ongoing operations and maintenance costs, environmental impacts, and likelihood of obtaining federal grant funding.

The Ioway Creek Resilient Infrastructure Flood Mitigation Project, included in the City’s Capital Improvements Plan for 2020/2021, is estimated to reduce flooding by two feet along the major flood damage center in the South Duff commercial and residential corridor. The project will include channel excavation of Ioway Creek 2,000 feet each direction from South Duff Avenue to improve creek capacity and resilience in large storm events. Additionally, the project will use stabilization techniques including natural channel design, streambank toe protection, pocket wetlands, and planting native vegetation to increase protection to area development.

Chronology

2010: Major flooding occurs; City Council establishes goal to mitigate flood impacts.

2013: Flood Mitigation Study completed

In 2013, the City of Ames worked with consultants HDR, to develop a strategy to mitigate challenges of area flooding. The final report was presented in January 2014.

To access the report, click here. 

On December 10, 2013, the City Council approved a series of flood mitigation measures targeted at, among several things, undertaking a "stream restoration" of Ioway Creek. This stream restoration project involves flood mitigation in the Ioway Creek channel. A central component includes conveyance improvements within the creek channel approximately 2,000 feet either side of the South Duff Avenue bridge.

2015: Consultant hired to design flood mitigation project

On October 27, 2015, City Council approved a professional services contract with WHKS & Co. of Ames, Iowa to design the flood mitigation project and to aid in the FEMA grant application process

2016: "Full build" (channel shaping) alternative selected

On November 29, 2016, as part of the Special Meeting of the City Council, direction was provided for staff to work toward Hydraulic Alternative No. 6 (2010 Event), which was for “full build” (channel shaping). This project would increase channel conveyance of Ioway Creek at the South Duff Avenue bridge by removing excess deposition of sediment, establish a multi-stage channel, reduce steepness and instability of highly eroding streambanks, provide thaw management, and establish a vegetated stream buffer. This project would improve the creek/bridge alignment, creek capacity, and hydraulic flows utilizing natural channel design (multi-stage channel to reconnect the creek with the floodplain), and would provide streambank toe protection and native vegetation stabilization for more resilience in large storm events.

2020: FEMA grant approved

The U.S. Department of Homeland Security's Federal Emergency Management Agency (FEMA) announced a grant to the State of Iowa that includes funding for Ames. The Ames City Council recently approved a funding agreement with FEMA to move the project forward. Through a nationally competitive grant process, the City of Ames is receiving funds for the Ioway Creek flood mitigation project to lower flood levels in the South Duff Avenue area. The grant will cover 75 percent of the project’s $4.9 million cost or $3.7 million.

2021: Flood Mitigation Tree Clearing

City Council approved a project March 9, 2021, to remove trees along Ioway Creek approximately 2,000 feet each direction of South Duff Avenue. Because Story County includes endangered or threatened bat species territory, the trees had to be removed by the end of March prior to bats returning to the area to nest.

Larger cottonwood trees being removed will be used to construct wood pallets. Other larger hardwood trees being harvested will be used to make items such as furniture and wood trim. The remaining trees will be stockpiled until they are removed as part of a flood mitigation project later this year.

The tree clearing is part of channel grading necessary to complete conveyance improvements within the channel to lower flood levels in the South Duff Avenue area. This flood mitigation project is funded with a $3,747,450 Federal Emergency Management Agency (FEMA) grant and local match of $1,249,150.