fema region 3 chesapeake bay storm surge project

FEMA Region 3Chesapeake BayStorm Surge Project

Brian BlantonSenior Research ScientistRenaissance Computing InstituteUniversity of North Carolina

11 August 2008USACE Norfolk District

RENCI Objective

• Extend/augment an existing modeling system into the Chesapeake Bay/Region III geographic area in order to compute of tropical and extra-tropical storm-induced water levels

– Model grids, DEM

• Incorporate STWAVE nearshore wave model into computational system

• Coordinate our work with the USACE and partners for data preparation and output data management, grid generation, storm and wind characterization, and wave model integration.

• I.e. : Communicate as much of our experience in the North Carolina Floodplain Mapping Project (NCFMP) as possible.

Three primary RENCI Phase 1 Tasks

Task 1 – Assembly of Digital Elevation ModelUNC/IMS, LuettichExisting topo/bathy data into larger consistent DEMNCFMP has identified potential issues regarding data quality,

bathymetric data, etc.

Task 2 – Grid Development and Modeling Consultation (UNC/IMS-Luettich)

Task 3 – Extend Computational System (RENCI/Blanton)

RENCI Personnel Involved

• RENCI– Dr. Brian Blanton : Coastal Oceanographer, Computational

Scientist– Margaret Blanchard : GIS/GRASS expert– Dr. Scott Madry : Geospatial Sciences– Ken Galluppi : Management– Howard Lander : Research Programmer

• UNC Institute of Marine Sciences– Dr. Rick Luettich : Coastal Oceanographer, ADCIRC Developer– Crystal Fulcher : SMS/ADCIRC grid development

NCFMP Overview

• RENCI/UNC + Collaborators

• Develop DEM• Build grids• Develop tropical storm statistics (JPM-OS) and tracks• Execute validation simulations• Build computational system (similar to Gulf/LACRR system)• Execute probabilistic tropical and extratropical storms• Post-simulation statistical analysis (development of flood-

frequency curves from simulations + JPM-OS storm weights)

Hillshaded Relief of North CarolinaStatewide LiDAR Derived Elevation

2121stst Century Data Century Data – Statewide Elevation– Statewide Elevation

Courtesy: J. Dorman, NCEM

Digital Elevation Model (RENCI/Madry)

• Combine recent LIDAR and bathymetric data sources into a seamless 10-meter DEM for coastal NC.

Data Sources/Patching Resulting 10-m DEM

ADCIRC Grid for Coastal NC Inundation

350K nodes, 10-20 meter nearshore, upland resolution

ADCIRC Grid Detail

Grid (triangles) in Wrightsville Beach AreaTry to align grid “lines” with coastline 20-30 meter beach resolution

Physical System

Computation of StillWater ELevation and wave SETUP component to total water level due to probabilistic Tropical and ExtraTropical systems.Numerical Models for different parts of the total water level

NCFMP Computational SystemWind/Pressure SimulatorHBL, WRF, NHC track etc

WaveWatch III for oceanic wave field

SWAN for nearshore wave field and radiation stress

ADCIRC for SWEL+Setup

Water level

Wave Force

NCFMP Coastal Model Suite

Statistical Storm Track Model (Vickery et al)

Historical Tracks20 hurricanes in 67 years (1940-2007)Annual Occurrence Rate = .338

Modeled Tracks324 parameter combinations (i.e. tracks/weights) for both Landfalling/Bypassing27 Stalling storms (675 total)Each storm weighted by probability of occurrence from parameter distributions/Joint Probability MethodUniform Landfall/Bypass Distribution

NCFMP Computational Effort

324 individual simulations, each with a probability of occurrence (Weighting from Joint Probability Method)

Each simulation takes about 12-16 hours on RENCI’s IBM BlueGene/L

256 processors per sim, 10-12 simultaneous simulations

1.2 million cpu-hours

Total Surge =Stillwater + Wave SetupADICRC+SWAN

Wave Setup ContributionSWAN

Chesapeake Bay/Region III

• DEM/grid development– Iterative process between grid

and validation simulations, as well as QA/QC process

– Time-consuming, labor intensive

• Storm statistics development– More Extratropical than NC

• Computational system used for validation runs– Embed STWAVE into workflow

• Identification of computational resources

• Website/Database