• Home
  • Research & Projects
    • On-Going Programs & In-Progress Projects
    • Completed Projects
    • ASFPM Library
  • About the Flood Science Center
    • Staff
    • Partners
    • Research Interests
    • Contact the Flood Science Center
  • Flood Science Center Products
Association of State Floodplain Managers

  • ASFPM Flood
    Science Center


  • Research &
    Projects


  • About
    the FSC


  • Contact
    the FSC


  • ASFPM
    Library


  • ASFPM
    floods.org

Home > Projects > Floodway Encroachment Standard: Minimizing Cumulative Adverse Impact

Floodway Encroachment Standard: Minimizing Cumulative Adverse Impact

Completed: June 2013.

Funding: ASFPM.

This report reviews the origin, use and establishment of regulatory floodways and provides an assessment of the impact of encroachments based upon allowing a 1-foot increase in flood elevations during the regulatory flood. The assessment evaluated impacts on the physical characteristics of the floodway (floodway width, water velocity and area inundated), damage to development in the floodplain and floodplain natural resources.

The Floodway Encroachment Standard: Minimizing Cumulative Adverse Impacts
Appendix B for The Floodway Encroachment Standard: Minimizing Cumulative Adverse Impacts
Sample Letter Requesting Full Conveyance Floodway [.docx]

References:

Federal Emergency Management Agency. 1978. The Floodway: A Guide for Community Permit Officials. Community Assistance Series No. 4
Federal Emergency Management Agency Region 10. 2004. A Summary of NFIP Policy for Local Officials
Goddard, James, et. al. 1978. Origin and Rationale of Criterion Used in Designating Floodways
U.S. Army Corps of Engineers. 1990 Hydrologic Engineering Center and the Philadelphia District prepared for FEMA Region 3. Floodplain Management Information Series: A Special Report - Procedures for Compliance with Floodway Regulations

Flood Science Center

Association of State Floodplain Managers, Inc.
©

 

ASFPM's Flood Science Center provides access to the tools, data, and resources that help advance the science of floodplain management. Learn more about us.