The City Commission approved payment of $29.662 million for the project at the September 21 meeting. The City Commission and the community have recognized the importance of the project and have been preparing for this needed improvement for more than 15 years. Construction will begin soon and is estimated to be completed by the end of 2023.
The Manhattan Levee was authorized by the federal government in 1954 and construction was completed in 1963. In combination with Tuttle Creek Reservoir, 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, and multiple elementary schools. Without these vital pieces of infrastructure, people in the City of Manhattan and most of the surrounding areas would not have access to fresh, clean water and the sanitary sewer system would not be able to function.
Of the total project cost, the City of Manhattan's share is $12,432,281. The US Army Corps of Engineers (USACE) is covering the remaining costs associated with the project. The City of Manhattan will be utilizing a stormwater utility surcharge fee of $1.66 per month to fund the city's debt payments on the project.
Even after the levee is completed, flooding will continue to be a major concern for the Manhattan community.
The city was founded in 1855 near the confluence of two major rivers. That was a common practice at the time to facilitate transportation and trade, despite the flooding risks the location presented. Many of the homes and businesses in Manhattan were built before 1984 when the City and County did not have access to flood insurance rate maps and adopted floodplain regulations. These areas are now recognized to be at risk for significant flooding.
Another compounding factor is that Manhattan is located at the bottom end of a large watershed which includes Wildcat Creek and the Blue River. The recent trends of severe rain events and flash flooding provide undeniable evidence that more efforts are needed to mitigate flood risk. In 2015, the City adopted more stringent floodplain regulations to better protect homes and businesses from flooding now and in the future. The regulations also limit the amount of fill that can be placed in a floodplain to reduce the impact on adjacent properties up and downstream of the fill site. This has been shown to curb the amount of new development in our floodplains, which was part of its intent.
However, hundreds of existing homes are still in a mapped floodplain, and these properties have been the focus of recent efforts. Riley County and the City jointly paid for a consultant to study if large dry detention ponds could be built on Fort Riley’s land and smaller detention ponds on farm and rangeland that would pull double duty as a stock pond and flood protect. Both study projects showed that the flood risk downstream of them would be significantly improved, but the cost would be another $30 million. The flood risk would also not be eliminated downstream because the ponds may be full or a huge rainstorm could fall somewhere else in the watershed and not in the ponds, thus the risk of flooding and cost of flood insurance would still be present. Additionally, and most importantly, most of the property owners where these stormwater ponds would be located were not in favor of the projects.
As mentioned, the City is mostly at the bottom of several watersheds, which limits the ability to create meaningful infrastructure improvements to protect against major flooding. Instead, City staff have focused efforts on moving people and structures farther away from the flood risk and making flood-prone areas more resilient. Since 2016, the City has leveraged over $2.1 million in state and federal funds to purchase 9 properties, and a total of 20 dwelling units, that were significantly damaged from past floods to get the residents out of harm's way. The City is actively working on federal grants to help more properties. Staff are also exploring ways to make Plaza West more resilient from flooding, while reducing flood risk in the area, and helping revitalize this highly visible and very important community commercial area.
Another idea is to create a dedicated funding source, like the stormwater utility fee, to mitigate flood-prone properties. This fund would correspond to a comprehensive flood mitigation plan that will work to address flooding for homes and businesses across the City. These projects will be more than just “buyouts.” Mitigation projects can take the form of floodproofing, elevating buildings, or constructing berms as flood protection. Progress is moving forward slowly as these mitigation projects will involve voluntary participation from hundreds of properties owners.
Manhattan has been dealing with the threat and aftermath of flooding for many decades. Addressing the threat will take significant time, funding, and effort. Please know that City staff are actively working to find meaningful solutions. If you would like to learn more, please explore the Know Your Flood Risk resources online at https://www.cityofmhk.com/2199/Know-Your-Flood-Risk or contact the Community Development Department.