PowerPoint Presentation

Downscaling storm surge models for engineering applicationsJohn BaughA. Altuntas, J. Rutledge, T. Dyer

Department ofCivil, Construction, and Environmental EngineeringNorth Carolina State UniversityResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Starting PointHow 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.

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Relevance to DHSGap 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.

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Interface ConditionsMay 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 processesResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Levee Failure Scenarios

Nesting for infrastructure assessment:

(3 different failures, flooding outlined in white)

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Year 5 ActivitiesSubdomain modeling of storm surge and wave effects using ADCIRC and SWANTime-varying topobathy in ADCIRC using a predetermined set of parametersAdditional means of reducing computational cost in simulation approachesResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#1. Storm Surge and WavesSWAN 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.

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#8Hurricane Fran and Cape Fear

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Hurricane Fran and Cape FearTPAR Files2D Spectra FilesParameterThresholdNodes%Nodes%Significant Wave Height5 cm707724.7250.087Wave Period1 sec714324.9530.185Peak Direction2012974.532180.761Conclusion: Using 2D spectra files to enforce the boundaries of a subdomain results in accurate and efficient computational modeling for engineering purposes.Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#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. Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

When bathymetric depth DP changesadjust water surface elevation ETA to maintain constant water column heightmark node wet for reevaluationremember prior DP values for consistency in calculating heights H0, H1, and H2

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

Test Case: Hatteras SubdomainExtracted from the western North Atlantic grid with refinements for simulating Isabel InletResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#3. Subduration ModelingSubduration 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.

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Step 0 : Begin with an ADCIRC model

ETA: Surface Elevation, DP: Bathymetric Depth

Subduration Modeling in ADCIRCResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Step 1 : Identify nodes that are part of the changed terrain.

Subduration Modeling in ADCIRC

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

Step 2 : Record a hot-start file before one of the changed nodes becomes wet.

Subduration Modeling in ADCIRC

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

Step 3 : Make changes to parts of the terrain (DP) in the fort.14 file.

Subduration Modeling in ADCIRC

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

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 ADCIRCResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Step 4 : Perform the hot-started run. Modified subdomain ADCIRC runs the hot-started simulation as it normally would.

Subduration Modeling in ADCIRCResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

Test Case: Cape Fear SubdomainExtracted from the western North Atlantic grid with a protective structure to prevent floodingResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Test Case: Cape Fear Subdomain

SimulationCPU Hours%Full Run:1080 100%Subdomain:282.59%Subduration:70.64%Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#ProductsSoftware 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.Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#

Research Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Prospective Collaborators and End UsersResearchersYoonhee Park / Professor Art Rice, Landscape Architecture, NCSU, Raleigh, NCFernando Magarinos Lamas, Mathematician, Physical Oceanography, Universidad Nacional Autonoma de Mexico, Mexico City, MexicoCelso Ferreira, Assistant Professor, George Mason University, Fairfax, VAConsultingMark Prater, Research Analyst, WeatherPredict Consulting, Kingston, RIEmergency ManagementSandy Sanderson, Director, Dare County Emergency Management, Manteo, NCFederal AgenciesTucker Mahoney, Coastal Engineer, FEMA Region IV, Atlanta, GAMax Agnew, Hydraulic Engineer, USACE New Orleans district, New Orleans, LAResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Prospective Collaborators and End UsersInternational AgenciesProfessor Weihua Fang, Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing, ChinaResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#Looking ForwardCase studies that draw on approaches developed in preceding years, demonstrating their benefit in enhancing the resilience of coastal communitiesInteractive software tools that support modeling activities for the actual case studies being performedDecision-making approaches that constitute best practices from the operations research community for coastal infrastructure designResearch Lead The University of North Carolina at Chapel HillCHC-R 5th Annual Meeting January 31-February 1, 2013#