With more than $1 billion worth of property located in Manhattan’s floodplain, a pilot project has been formulated to prepare for future floods.
The Big Blue River is the largest tributary of the Kansas River, and flows for approximately 359 miles through Nebraska and Kansas. It intersects with the Kansas River east of Manhattan. It discharges into Tuttle Creek Lake, northeast of Manhattan. The Big Blue River basin covers most of northern Kansas, including Manhattan.
A public open house held last Wednesday to discuss the pilot program. The multi-year Big Blue River Pilot Project would develop flood forecast inundation mapping on the Big Blue River to help determine what areas are at risk for flooding, develop future condition flood inundation, establish floodplain management plans and implement other measures to keep people safe.
Tuttle Creek Lake is a major structural component that helps regulate water discharge. Tuttle Creek Dam is an integral part of the floodplain management system today.
“There are obviously some structural components in (the Big Blue River) basin,” Robert Ott, director of public works for the city of Manhattan, said.
Another structural component that helps with floodplain control is a levee system, which helps protect downtown Manhattan, Ott said. There is approximately 29,000 feet of levee that protects more than 10,000 residents and 1,600 acres of land.
The levee was finished in 1963. The City of Manhattan and Army Corp of Engineers have further studied the levee since the 1993 flood. According to the city commission agenda from January, “The City and the Corps of Engineers became very concerned that the levee may not provide the designed level of protection.”
A technical advisory group will help generate ideas for implementation to help increase safety for all Manhattan residents from flood threats. The advisory group will work with a public action group to help minimize flood risks. Ideas mentioned included identifying evacuation routes for residential and commercial areas and raising the levee. The levee currently meets FEMA standards, which according to the Water and Science Technology Board, “provides reasonable assurance that the levee will provide protection from a 100-year flood.” A 100-year flood is a water elevation that has a 1-in-100 chance of being exceeded in a year, according to FEMA.
Flood insurance is typically required for homes with federally backed mortgages. Judy Parks, retiree in the Dix’s Addition subdivision of northern Manhattan, is not required currently to have flood insurance. After the pilot project is implemented, her home will be considered part of the floodplain.
Parks wanted to know how her flood insurance was going to be affected since zoning influences the premiums homeowners pay. For many families with a fixed income, it’s important to know how much to budget for insurance. She said this will affect students, military personnel and university employees.
Linda Morse, chair of the Manhattan Area Planning Board, said the project is a positive step. Some of Manhattan’s short-term population, such as students and military, may not think of potential issues like sewer backup or replacing the driveway after flooding, she said.
History of flooding
In Manhattan’s history, the largest magnitude flood on record occurred in 1844. Other years with significant floods include 1903, 1951 and, most recently, 1993.
“In ’93, they didn’t have very good predictive analysis … who should evacuate next, who’s going to get what,” Ott said.
The aspect of research and education will be important in the process. There are plans to develop a website similar to the Wildcat Creek Watershed Council’s website. The website includes on-site data collection that gauges stream levels, which can be helpful for flood inundation mapping. This helps citizens understand the flood and its impacts in real time. The current website’s purpose is to actively update the affected flood areas in an effort to better prepare people for a flood situation.
Ott said the mapping element of the project will forecast flood levels for families, be of assistance when the waters rise, and better answer the question of how much water will flood certain areas and how quickly to evacuate people.
Groups participating in the program include the Department of Water Resources, U.S. Army Corp of Engineers, FEMA, City of Manhattan officials and state floodplain managers from Riley and Pottawatomie counties.