HEC-RAS 2D: The Right Tool for the Job?
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HEC-RAS 5.0 was released in 2016 with two-dimensional (2D) modeling capabilities and has completely since revolutionized the world of floodplain modeling.

Examples applications where 2D modeling is useful include rivers with significant meanders or poorly defined channels (i.e. braided systems). However, the regulatory framework of floodplain permitting is yet to catch up with 2D modeling advancements. Federal Emergency Management Agency (FEMA) map revisions requires the use of 1D model to calculate water surface elevation rise due to proposed development and floodway analysis. The insights from 2D model is still useful in informing the 1D models for floodplain permitting.

The presentation will showcase a series of applications for HEC-RAS 2D modeling, including leveraging the strengths of 2D modeling to inform 1D modeling or in combination as a 1D/2D model. Four case studies will include applications in FEMA floodplain mapping, dam breach analyses, and flood impacts from historic storm events. Featured projects will highlight the benefits and pitfalls of 2D modeling with many "Lessons Learned." After this talk, attendees will be able to identify applications best suited for HEC-RAS 2D, HEC-RAS 1D as well as combination of both.

Publication Summary

  • Geosyntec Authors: Rishab Mahajan, Emily Campbell, Matt Bardol
  • All Authors: Rishab Mahajan, Emily Campbell, Matt Bardol
  • Title: Illinois Association for Floodplain and Stormwater Management (IAFSM)'s 2020 Annual Conference
  • Event or Publication: Event
  • Practice Areas: Water and Natural Resources
  • Citation: Geosyntec staff presented on Floodplain and Stormwater Management at the Illinois Association for Floodplain and Stormwater Management (IAFSM)'s 2020 Annual Conference in Tinley Park, Illinois on March 11-12, 2020.
  • Date: March 11-12, 2020
  • Location: Tinley Park, Illinois
  • Publication Type: Platform Presentation