Floodway No-Rise Certification

A “Regulatory Floodway” means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height. Communities must regulate development in these floodways to ensure that there are no increases in upstream flood elevations. For streams and other watercourses where FEMA has provided Base Flood Elevations (BFEs), but no floodway has been designated, the community must review floodplain development on a case-by-case basis to ensure that increases in water surface elevations do not occur, or identify the need to adopt a floodway if adequate information is available.

Encroachments are activities or construction within the floodway including fill, new construction, substantial improvements, and other development. These activities are prohibited within the adopted regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses that the proposed encroachment would not result in any increase in flood levels.

Any project in a floodway must be reviewed to determine if the project will increase flood heights.

An engineering analysis must be conducted before a permit can be issued. The community’s permit file must have a record of the results of this analysis, which can be in the form of a No-Rise Certification. This No-Rise Certification must be supported by technical data and signed by a registered professional engineer. The supporting technical data should be based on the standard step-backwater computer model used to develop the 100-year floodway shown on the Flood Insurance Rate Map (FIRM) or Flood Boundary and Floodway Map (FBFM).

If you’re considering constructing within a designated floodway, you will need to submit the following items to Planning & Development Services, Building Department for review by our Building Official.

1. A cover/transmittal letter defining the scope of work

2. A complete FEMA no-rise certification analysis packet signed by a registered professional engineer

3. Application