Floodway surcharge is the amount of increased flooding that would occur if the floodway fringe is filled. This increase is limited by CFR 60.3 to one-foot. This analysis has historically been analyzed based upon loss of conveyance. Loss of floodplain storage has not traditionally been analyzed.
ASFPM has drafted outreach materials that can be used when a mapping project is initiated to improve community understanding of the impacts of floodway surcharge. The project included the development of a fact sheet, an improved graphic for powerpoint and several case studies where communities have developed mapping and/or regulations to limit the impact of fill in the floodplain.
ASFPM has developed a floodplain mapping and regulations No Adverse Impact How-to Guides. Some best practices included in the guide will also be highlighted.
Please join us for this free webinar on the floodway surcharge and how to reduce the impact.
Presenters:
- Alan Lulloff, PE, CFM - ASFPM Flood Science Center
- Dave Carlton, PE, CFM - DKCarlton and Associates
- Tim Trautman, PE, CFM - Charlotte Mecklenburg, NC
- Richard Reynosa, PE, CFM - San Marcos, TX
Agenda:
- Webinar Logistics - Kevin Currie, ASFPM
- Introduction - Alan Lulloff
- The Floodway Surcharge Concept - Alan Lulloff
- Higher standards case studies - Dave Carlton
- King County, WA: County zero-rise floodway - Dave Carlton
- Charlotte Mecklenburg: Two Floodways - Tim Trautman
- San Marcos, TX - All of SFHA is Floodway - Richard Reynosa
- Questions/Discussion
Slides: Floodway Surcharge
Recording: Floodway Surcharge
Q & A: Floodway Surcharge
Related Materials:
An Introduction to Floodway Surcharge: An Outreach Packet (2023)
Understanding Floodway Surcharge Graphic [Powerpoint]
Floodway Outreach Project page
Note: Viewing the recording of this webinar is not eligible for CECs.
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