Floodplain Information


What is a Floodplain?

Land adjacent to streams and rivers which does not carry water under normal weather conditions.

What does it do?

During large storm events, streams, and rivers use the floodplain to temporarily store and convey water until the storm stops and water downstream has had a chance to go down.

How are they formed?

Naturally and over time with each storm event.  Floodplains, rivers, and streams are constantly changing by the force of Mother Nature, even during small rain events.  Water moves soil every time it rains or snow melts, constantly changing the landscape.

Additional Information

Find more information about how to live in and around the floodplain:

City of Manhattan Floodplain Information

Contact the Riley County Floodplain Manager at 785-537-6332

Flood Insurance Information

Cheaper Flood Insurance (pdf) - 5 ways to lower the cost of your flood insurance premium

Do I need a Floodplain Development Permit (pdf) (FDP)?

Do I need a Floodplain Development Permit (pdf) in order to build in the floodplain? Yes.

Application for Floodplain Development Permit (pdf)

A FIRMette is a full-scale section of a FEMA Flood Insurance Rate Map (FIRM) that you create yourself online by selecting the desired area from an image of a Flood Insurance Rate Map. The FIRMette also includes the map title block, north arrow, and scale bar. There is no charge for making a FIRMette. Because a FIRMette is a full-scale section of an official FEMA Flood Insurance Rate Map, it can be used in all aspects of the NFIP, including floodplain management, flood insurance, and enforcement of mandatory flood insurance purchase requirements.

For additional flood information: