Evaluation of Preliminary DFIRMs Phase I Findings

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Evaluation of Preliminary DFIRMsPhase I
Findings

• Terrebonne Parish
• June 22, 2009

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Creation of a BFE
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The Models
Still Water Elevation 1. ADCIRC Advanced
Circulation Model for Coastal Ocean
Hydrodynamics. Developed by the USACE to
determine the SWEL or storm surge levels for
coastal LA. 2. STWAVE a numerical model used to
generate and transform w aves to the shore. 3.
JPM-OS provides a means to model the effects
and probabilities of storms that historically
have not occurred. Wave Height 4. WHAFIS
FEMAs wave model, based on transects.
Topographic characterics along each transect
serve as inputs in the model (ground elevation,
SWEL, vegetation, and physical features).
Preliminary DFIRMs
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Summary of Phase I Findings

• Review of FEMA information indicates numerous
  scientific and technical deficiencies exist in
  the DFIRMs
• Primary deficiency appears to be the treatment
  of barriers in FEMAs models
• The accurate horizontal location and vertical
  elevation of barriers should be identified and
  revised in the models (ex. Thompson Road
  Extension)

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Task 4.3 Review Set-up of Surge Models Used in
the FIS
GRAPHICs dokka
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Task 4.3 Review Set-up of Surge Models Used in
the FIS
Approximately 3 miles north of Dulac, east of
Grand Caillou Road Mis-location of barriers.
Barriers defined by FEMA, green Interagency
Performance Team levees, yellow Red dots, all
barriers. Note major gap in barrier near center
of picture.
GRAPHIC
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Possible Options
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Discussion of Phase II

• Establish/Confirm Parish Objectives
• Insurance Rates, Flood Protection, etc.
• Tailor Scope of Work to Target Objectives
• Ensure models accurately depict barriers
• Identify barriers that exist today
• Identify barriers designed, funded, and at least
  50 complete
• Establish horizontal accuracy
• Remodel and re-map
• Prepare Appeal/Protest Document
• 90-Day Appeal Period June 24 to September 21,
  2009

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