1. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 1

2. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 2 Starting Point How do we assess the effects of storm surge on civil infrastructure? Engineering design scenarios imply topographic changes, as do failures. Hundreds of cases may be worth considering.

3. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 3 Relevance to DHS Gap being addressed: No computationally tractable approach exists for assessing storm surge effects on proposed infrastructure changes and improvements. The DHS mission includes managing risks to critical infrastructure, ensuring resilience to disasters, and mitigating hazards.

4. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 4 Interface Conditions May be formulated in a variety of ways: – One-way nesting (Spall and Robinson 1989) – Two-way nesting (Debreu and Blayo 2008) – Full coupling (Cailleau et al. 2008) Used to resolve smaller spatial and temporal scale processes

5. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 5 Levee Failure Scenarios Nesting for infrastructure assessment: (3 different failures, flooding outlined in white)

6. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 6 Year 5 Activities 1.Subdomain modeling of storm surge and wave effects using ADCIRC and SWAN 2.Time-varying topobathy in ADCIRC using a predetermined set of parameters 3.Additional means of reducing computational cost in simulation approaches

7. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 7 1. Storm Surge and Waves SWAN is a phase-averaged spectral wave model with two possible types of boundary conditions: – TPAR files contain significant wave height, wave period, peak direction, and directional spread. – 2D Spectra files contain N discrete frequencies and M directions.

8. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 8

9. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 9 Hurricane Fran and Cape Fear

10. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 10 Hurricane Fran and Cape Fear TPAR Files2D Spectra Files ParameterThresholdNodes% % Significant Wave Height5 cm707724.7250.087 Wave Period1 sec714324.9530.185 Peak Direction20⁰12974.532180.761 Conclusion: Using 2D spectra files to enforce the boundaries of a subdomain results in accurate and efficient computational modeling for engineering purposes.

11. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 11 2. Time-Varying Topobathy The result of a net transport of sand along the ocean bottom or the overtopping and collapse of a dune, or the failure of engineered structures such as levees and geotubes. To accommodate, allow time-varying changes in bathymetric depth DP using a predetermined set of parameters.

12. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 12 When bathymetric depth DP changes – adjust water surface elevation ETA to maintain constant water column height – mark node wet for reevaluation – remember prior DP values for consistency in calculating heights H0, H1, and H2

13. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 13 Test Case: Hatteras Subdomain Extracted from the western North Atlantic grid with refinements for simulating Isabel Inlet

14. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 14

15. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 15 3. Subduration Modeling Subduration modeling is introduced as a means of downscaling hurricane storm surge models in time. The hot-start feature of ADCIRC allows users to begin a run from a specified timestep using initial conditions obtained from a previously performed run. This feature is used to reduce the total runtime of series of simulations where users have made topographic or other changes to a model.

16. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 16 Step 0 : Begin with an ADCIRC model ETA: Surface Elevation, DP: Bathymetric Depth Subduration Modeling in ADCIRC

17. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 17 Step 1 : Identify nodes that are part of the changed terrain. Subduration Modeling in ADCIRC

18. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 18 Step 2 : Record a hot-start file before one of the changed nodes becomes wet. Subduration Modeling in ADCIRC

19. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 19 Step 3 : Make changes to parts of the terrain (DP) in the fort.14 file. Subduration Modeling in ADCIRC

20. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 20 Subdomain ADCIRC has been modified so that the original ETA of a changed node is initially set to be equal to changed DP, during a hot-started run. Subduration Modeling in ADCIRC

21. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 21 Step 4 : Perform the hot-started run. Modified subdomain ADCIRC runs the hot-started simulation as it normally would. Subduration Modeling in ADCIRC

22. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 22 Test Case: Cape Fear Subdomain Extracted from the western North Atlantic grid with a protective structure to prevent flooding

23. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 23 Test Case: Cape Fear Subdomain SimulationCPU Hours% Full Run:1080100% Subdomain:282.59% Subduration:70.64%

24. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 24 Products Software tools for subdomain modeling, modifications to ADCIRC, user scripts, visualization tools, user guide already being distributed. Theses, technical reports, conference talks, articles under review and in preparation.

25. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 25

26. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 26 Prospective Collaborators and End Users

27. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 27 Prospective Collaborators and End Users

28. Research Lead  The University of North Carolina at Chapel Hill CHC-R 5 th Annual Meeting January 31-February 1, 2013 28 Looking Forward