Meeting/Event Information

EWRI: Improving Flood Risk Identification & FEMA Mapping Using HEC-RAS 1D/2D

July 26, 2018
11:30 AM to 1:30 PM
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Jacobs Engineering
5995 Rogerdale Rd
Houston, TX 77072


  • Lonnie Anderson, P.E., Pape-Dawson Engineers, Inc.
  • Ataul Hannan, P.E., Harris County Flood Control District

Speaker biographies are provided below.


Approximately 60 to 70% of reported flooding from the Memorial Day 2015, Tax Day 2016, and Harvey 2017 storms within Harris County and surrounding areas occurred outside of FEMA’s currently mapped 1% event floodplain.  This high percentage indicates that better flood risk depictions need to be made in coastal areas. The current FEMA maps are based on steady state 1D modeling. With our coastal topography 1D modeling does not fully capture the looped rating curves of channels caused by backwater effects, the complicated flow patterns in the overbank that occurs during extreme events from runoff both entering and leaving the channels.

In the spring of 2016, the USACE Hydrologic Engineering Center released HEC-RAS Version 5.0 providing a free software capable of 2-dimensional floodplain modeling. The latest HEC-RAS version, Version 5.0.5 was released June 13, 2018.  This version provides additional tools for improving 2-dimensional floodplain modeling.  With the new tools available in Version 5.0.5 it is conceivable that floodplain modeling for No Adverse Impact studies as well as FEMA regulatory models can be accomplished in a coupled 1D/2D unsteady-state model.

This presentation will provide an overview of current HEC-RAS V5.0.5 2D modeling capabilities, how its use can better identify flood-prone areas and guide flood damage reduction efforts.  Harris County Flood Control District will also present discussion of items they are currently investigating to improve flood risk depictions including the future FEMA map update required to incorporate Atlas 14’s revised rainfall data.  This discussion will also include a look at the complexity and limitations of event-based modeling approaches and transient watershed conditions as it applies to regulatory floodplain mapping.


  • 11:30 a.m.   Registration, Networking, and Box Lunches
  • 12:00 noon   Presentation and Q&A
  • 1:25 p.m.    EWRI Announcements
  • 1:30 p.m.    Adjourn


ASCE Members:         $30
Non-Members:           $50

Registration includes a boxed lunch.



Please pay by credit card online after clicking the "Register Now" button. 

If you must pay by check, please make the check payable to "ASCE Houston Branch" and send it to Michael Bloom, R. G. Miller Engineers, Inc., 16340 Park Ten Place, Suite 350, Houston, TX 77084, or bring a check to the event.

SPONSORS:  Sponsorships are available for $250 each. Sponsors will receive:

  • One complimentary lunch; and,
  • Recognition on event posters, welcome screens, and verbally during the event (please email your high-resolution logo to mbloom at rgmiller dot com after you purchase your sponsorship).

Please note that attendees affiliated with the sponsoring organization will still need to separately register and pay the member or non-member cost.

Proceeds will cover the event cost and benefit EWRI-Houston activities.

Please purchase your sponsorship online by clicking on the "Register Now" button.



Lonnie Anderson is a Principal Engineer with Pape-Dawson Engineers in their Houston office. He has more than 25 years' experience in civil engineering performing detailed hydraulic and hydrologic modeling. Over the past 5 years, he has been an active beta tester for USACE HEC-RAS 2D, drafted 2D and 1D unsteady state HEC-RAS guidance manuals and provided training on the use of HEC-RAS 1D/2D.


Ataul Hannan is working as Planning Division Director for the Harris County Flood Control District. The Planning Division devises the plans that guide the District CIP and identifies the projects that the District designs and constructs.  In addition to identifying projects, the Planning Division also provides critical support for new projects and other District responsibilities by managing right-a-way acquisition, environmental regulatory support, stormwater quality, and coordination with FEMA.  Mr. Hannan has over twenty years of experience in watershed management and water resources engineering. Prior to joining the District, he provided technical support to FEMA’s NFIP and Disaster Relief Program.  He was the lead project engineer for Tropical Storm Allison Recovery Project (Harris County) and North Carolina statewide mapping project. He managed numerous Flood Insurance Studies in many states. Mr. Hannan is the author of more than 75 papers and abstracts on a variety of topics.  Mr. Hannan has extensive experience in modeling as well as advanced 1D/2D software.  He is registered as a Professional Engineer in the State of Texas and Virginia. He is also a Certified Flood Plain Manager.


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$50.00 Guest

$250.00 Sponsor


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