The Manhattan Levee was authorized by the federal government in 1954 and construction was completed in 1963. The levee protects approximately 1,600 acres of land, 7,600 residents, and $1.4 billion of public and private infrastructure, including the post office, water treatment plant, wastewater treatment plant, multiple elementary schools, and the ninth grade center.
However, the levee does not provide the level of flood protection to which it was originally designed. A feasibility study conducted by the The U.S. Army Corps of Engineers (USACE) recommends raising the levee by an average of 1.5 feet, with a maximum raise of 3.3 feet in some sections, in order to protect the community from a 1% (or 100 year) flood event.
The USACE has entered into a public partnership agreement with the City to raise 4 miles of the levee along Hayes Drive to the Big Blue and Kansas Rivers. The project will also rehabilitate and/or replace the original gate structures and technology as needed. The agreement stipulates the City will pay for 35% of the project costs.
Timeline: Design will be complete in 2020. Construction will occur from 2021-2023.
Total Project Cost: $33 Million
Federal match: $19.6 million
Local match (0.3% Sales Tax): $13.4 million
During the peak of the 1993 flood, with approximately 58,800 cubic feet per second (cfs) flow released from Tuttle Creek Lake and approximately 100,000 cfs flowing in the Kansas River, the water surface approached the top of the levee on the Big Blue River segment. The levee system was originally designed to pass significantly higher flows with a greater margin of safety. The City and the USACE became very concerned that the levee may not provide the intended level of protection when it was originally designed.
Over the course of the next 10 years, the USACE completed a fully federally-funded reconnaissance study in 2004 and determined raising the levee and improvements to gate structures were necessary to provide the necessary protection. Since then, it took nearly 15 years for the federal government to conduct a feasibility study and approve funding for the project.