1. Landuse Attributes for Overland Wave Modeling
Paul Carroll, PE

2. Coastal Methodology Overview
Storm surge modeling with the ADvanced CIRCulation Model (ADCIRC)
Wave modeling with the WaveWatch III Model and the Simulating Waves Nearshore (SWAN) Model
Overland wave analysis using FEMA’s Wave Hazard Analysis for Flood Insurance Studies (WHAFIS) Model
Hazard Zone Mapping
ADCIRC
SWAN
Water level, currents
Wave radiation stress
WHAFIS

3. Overland Wave Modeling
Wave Height Analysis for Flood Insurance Studies – WHAFIS
1-D model – interfaced with GIS-type software allows for increased model transect density
Capable of variable obstructions including vegetation types and buildings

4. Overland Wave Modeling
1-D Approach based on:
Water depth
Wave decay
Wave regeneration

5. Overland Wave Modeling

6. Landuse Characterization
Open or Inland Fetch
Rigid Vegetation
Buildings
Marsh

7. Level of Effort to Appropriately Characterize a Vegetation Polygon
Level of input detail should be commensurate with the ability of the model to reflect a change in Wave Height
So how precise should values be……?
Input data need to be regionally reflective
So how useful are spot measurements……?

8. VE Categories and Testing
Mean Spacing – Beyond 50-ft nominal impact

9. VE Categories and Testing
Mean Spacing – Max delta of 1.0 across the sub-cat range

10. VE Categories and Testing
Mean Trunk Diameter

11. Suggested Categories for Vegetated Tracts

12. Level of Effort to Appropriately Characterize a Building Polygon
Level of input detail should be commensurate with the ability of the model to reflect a change in wave height
Input data need to be regionally reflective

13. Locate modeling transects in regionally representative areas

14. Delineate areas of uniform building density

15. Transect is sub-divided into sections, wave computations are performed at each node

16. Typically 0 or 1 row of buildings within each segment

17. Attributing Modeling Transect Segments

18. Suggested Categories for Building Areas
90%
65%
40%
25%

19. Characterizing Landuse in mixed BU/VE areas

20. Elevated 100% Open On-Grade 65% Open On-Grade 65% Open Rigid
Vegetation
Inland Fetch (IF)
Open Fetch (OF)
11/28/2018

21. Mapping Results
Transect 2
Transect 3
Transect 1

22. References
BakerAECOM, September DRAFT Task A.2.a, c., d., & e: Interim Report, Analysis of ADCIR Mesh Size and Resolution in Six Recent Coastal FISs and Requirements for a Northeast Florida/Georgia FIS.
North Carolina Storm Surge Study. Dorman, John., Blanton, Brian., et. al.
Atlantic Ocean and Gulf of Mexico Coastal Guidelines Update. FEMA , 2007.