Flood hazard maps, also known as Flood Insurance Rate Maps (FIRMs), are important tools in the effort to protect lives and properties in Manhattan. They indicate the risk for flooding throughout Riley County and Manhattan. However, the current maps need to be updated as some areas were never mapped in detail, and other areas haven’t been re-mapped in more than 10 years. Through time, water flow and drainage patterns have changed dramatically due to surface erosion, land use and natural forces. The likelihood of riverine and low land flooding in certain areas has changed along with these factors.
New maps (found on this site as Preliminary DFIRMs) include the most current rainfall, elevation and other key data with the latest modeling technology to provide the most up-to-date picture of the area’s flood risk. The result: a better picture of the areas most likely to be impacted by flooding and a better foundation from which to make key decisions.