1. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC SWIMS Hawaii Hurricane Inundation Fast Forecast Tool Jane McKee Smith, Andrew B. Kennedy, Alexandros A. Taflanidis, Joannes J. Westerink, Kwok Fai Cheung, and Thomas D. Smith

2. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Introduction Island communities are vulnerable to storms Nowhere to evacuate Infrastructure within hazard zone Unique/Important Island Features & Physics Steep slopes Reef roughness Reef flat dynamics (ponding, wave reformation) Importance of waves Growth of long waves

3. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Pacific Islands Land-Ocean Typhoon (PILOT) Exp. Surge & Wave Island Modeling Studies (SWIMS) Products Field data sets : Guam Saipan Oahu, Hawaii St. Croix, VI Laboratory Data Sets (2D/3D) Model Improvements Fast Forecasting System Objectives: Collect coastal processes data under typhoon and high-wave conditions in island environments Improve model physics and tools for island application for emergency management and design

4. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC SWIMS Fast Forecasting System Pre-run storms with high-fidelity models ADCIRC unSWAN BOUSS-1D Create database of response Develop surrogate model to forecast inundation Deterministic Probabilistic Hurricane Evacuation Studies Mass Management System Interface for Emergency Managers (MMS)

5. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Potential Impacts Cat 4 storm on Oahu Severe damage to air & sea ports Island-wide power and communications outages (1 month or longer) 80% of homes destroyed 650,000 people seeking shelter Since 1950: Nina (1957) Dot (1959) Iwa (1982) Estelle (1986) Iniki (1992) Hurricane Iniki

6. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Five base storm tracks from hurricane climatology (NWS) Tracks shifted to give different landfall locations Tracks and parameters varied to give a matrix of potential storms (bound most possible landfall scenarios) Storm Selection: Tracks

7. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Storm Selection Base Tracks 120,150,180, 210, 240 deg Central Pressure 940, 955, 970 mb Radius of Maximum Winds 30, 45, 60 km Forward Speeds 7.5, 15, 22.5 kts 15 Landfall Locations (Oahu and Kauai)

8. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Wave and surge prediction (high-fidelity model) High-resolution grid Oahu and Kauai SWAN+ADCIRC wave and circulation models Validation with tides and Hurricane Iniki Wave runup prediction BOUSS-1D Wave, surge, and runup inundation database and predictions for new events Surrogate modeling Wave, Surge, and Runup Inundation Database

9. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Domain incorporates Hawaiian Islands and north central Pacific Ocean Grid resolution ranges from 30 m on land and in the nearshore to 5000 m in deep water Incorporates high resolution features, channels, coral reefs and wave breaking zones 1,590,637 nodes 3,527,785 elements Grid Domain

10. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC

11. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC ADCIRC solves for water surface elevations and currents in two dimensions SWAN solves the wave action density and is a phase- averaged wave model with wave energy represented by a spectrum ADCIRC passes water elevation and currents to SWAN SWAN passes wave radiation stresses to ADCIRC Models run on in parallel on the same grid SWAN+ADCIRC Model – Coupled Waves and Currents on Unstructured Grids

12. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Hurricane Iniki (1992)

13. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Hurricane Iniki Water Levels NOAA water elevation gauges

14. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Storm Atlas

15. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Wave Height (ft) for Category 4 storm, forward speed of 7.5 knots

16. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Wave Height (ft) for Category 4 storm, forward speed of 22.5 knots

17. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC SWAN+ADCIRC gives wave heights and still water levels near shore Wave runup (intermittent wave inundation at the shore) can be dominant in some storms Hundreds of meters inland, several meters more elevation than still water level During Hurricane Iniki (6-8m) Two approaches to wave runup Parameterized relations predict runup given the significant wave height, wave period, and basic nearshore bathymetry Boussinesq modeling along one-dimensional transects Hawaiian topography too complex to use parameterized results Wave Runup Analyses

18. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Use one dimensional Boussinesq model BOUSS-1D to compute runup over 750 transects on Oahu, 443 on Kauai Phase resolving - represents each individual wave through time and space Forced by waves and water level at offshore boundary of transect Precompute runup for a matrix of storms and water levels SWAN+ADCIRC computations of waves, water level projected onto pre-computed results to give runup for any storm Wave Runup Analyses

19. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Time(s) Runup Elevation (m) Cross-shore Distance (m) Offshore wave time series (m) Wave Runup Analyses: Boussinesq Model Output along a Transect

20. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Pre-run suite of basis hurricane scenarios Moving least-squares response surface surrogate model Predict the output for any new hurricane scenario Basis hurricane scenarios New hurricane scenario Surrogate Model

21. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Comparison of Hurricane Output Predictions Surrogate model predictions High-fidelity model predictions

22. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Cone of potential tracks Expected hurricane track Uncertainty in all hurricane parameters (described by probability models) Use the surrogate model to predict Deterministic scenario Average (expected) output Output with certain probability of being exceeded Probability (%) of exceeding a specific threshold Current hurricane location Probabilistic Prediction of Hurricane Output (Risk)

23. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Graphical User Interface

24. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC

25. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC

26. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Summary Fast Forecasting Tool provides framework for dynamic and fast evaluation of waves, surge and inundation High-fidelity, high-resolution models to simulation hundreds of hurricanes Query the database for deterministic or probabilistic estimates Results in seconds to minutes Simulations for the Big Island and Maui County are running now (~800 runs) Ongoing work in Guam, too…

27. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Guam Jackson State U.: Himangshu S. Das and Hoonshin Jung Grid: circular domain (6 deg radius ~ 666 km) Resolution 14 km to 25 m 239,664 nodes and 473,083 elements

28. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Guam -- Validation (Nockten)

29. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Guam -- Validation (Nida)

30. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Synthetic Storms for Guam (~750)

31. US Army Corps of EngineersCoastal and Hydraulics Laboratory - ERDC Questions