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Flood Insurance: The Risk of Not Being Insured

FEMA Preliminary Data

Project Data Centers

Great Lakes Coastal Flood Study, 2012 Federal Inter-Agency Initiative: Guidance Documents and Reports

Great Lakes Coastal Analysis and Mapping Guidance Updates Comparison
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Topic Reference Section in Appendix D.3
(May 2012)
Summary of 2012 Update
(May 2012)
Summary of Effective Guidance
(February 2002)
Water Levels D.3.4.4
  • Recommends storm surge modeling
  • Considers water level variability over the period of 1960 to 2010
  • Measured data for model calibration
  • Ice cover impacts considered
  • USACE Revised Report on Great Lakes Open-Coast Flood Levels (1988)
  • Water level variability not addressed
  • No consideration of ice cover
Incident Wave Conditions D.3.4.3
  • Recommends lake-wide wave modeling
  • Measured data for model calibration
  • Shoreline buffering protection provided by Ice cover considered
  • Hindcast data (WIS) recommended source
  • ½-year (Lake Ontario) and 3-year (Lakes Erie, Huron, Michigan, Superior) identified as appropriate wave conditions for flood insurance study
  • Wave period identified as critical characteristic
  • No consideration of ice cover protecting shoreline from waves
Nearshore Wave Transformation D.
  • 2-D wave modeling recommended for shoaling areas of complex bathymetry
  • 1-D wave modeling (CSHORE) for surf zone
  • Simplified assessments for sheltered waters based on fetch analysis (Automated Coastal Engineering System) recommended
Erosion D.3.7
  • Setting specific approaches provided
  • CSHORE model recommended for assessing surf zone processes
  • Beach morphology change due to lake level cycles
  • Qualitative assessments based on historic response data as available
  • Recommendations for sandy dune and bluff presented
Coastal Structures D.3.8
  • Evaluation based on Criteria for Evaluating Flood Protection Structures for NFIP Purposes (FEMA, 1990)
  • Treatment of failed and removed coastal armoring structures
  • Coastal levees
  • Evaluation based on Criteria for Evaluating Flood Protection Structures for NFIP Purposes (FEMA, 1990)
Wave Setup D.3.5.1
  • 1-D model (CSHORE) recommended
  • No consideration of wave setup
Wave Runup D.3.5.2
  • 1-D model (CHSORE) recommended
  • Mase equation for areas where 1-D model not applicable
  • Coastal Engineering Manual (CEM) for vertical structures and stepped walls/embankments
  • FEMA Great Lakes Wave Runup Model (GLWRM)
Wave Overtopping D.3.5.3
  • Coastal Engineering Manual (CEM) & EurOtop
  • Provides references for overtopping analysis
Flood Hazard Mapping D.3.9
  • VE Zones not mapped without prior FEMA approval
  • Definition of SFHA and mapping guidelines