TR-08-08 Report for State of North Carolina Floodplan Mapping Project Costal Flood Analysis System

Brian Blanton (RENCI), Scott Madry (RENCI), Ken Galluppi (RENCI), Kevin Gamiel (RENCI), Howard Lander (RENCI), Mark Reed (RENCI), Lisa Stillwell (RENCI), Margaret Blanchard-Montgomery (RENCI), Rick Luettich (UNC), Craig Mattocks (UNC), Crystal Fulcher (UNC), Peter Vickery (Applied Research Associates/IntraRisk), Jeff Hanson (US Army Crops of Engineers), Eve Devaliere (US Army Crops of Engineers), John McCormick (Costal Risk Technologies), Technical Report TR-08-08, Report for State of North Carolina Floodplan Mapping Project Costal Flood Analysis System, Renaissance Computing Institute, 2008.

As part of the State of North Carolina Department of Emergency Management Floodplain Modernization Program, a partnership was assembled to develop a state-of-the-art system to compute still-water levels along the North Carolina coastal region waters. This was developed for input into floodplain analysis systems, as required by the Federal Emergency Management Agency (FEMA). Experts in the fields of coastal storm surge, wind-driven waves, Geospatial Information Systems (GIS), and high-performance computational systems have worked together in this effort to further advance North Carolina’s leading role in flood analysis and mapping. The project partners are: Renaissance Computing Institute (RENCI), University of North Carolina (UNC)-Chapel Hill Institute of Marine Sciences, US Army Corps of Engineers (USACE) Duck Field Research Facility, Applied Research Associates (ARA)/IntraRisk, Coastal Risk Technologies, and Dewberry. The overall approach was to assemble the pieces of the system to enable the computation of still water levels using recent developments in similar projects (e.g., Louisiana Coastal Protection and Restoration/FEMA).

One of the primary components of this project was the assembly of a state-of-the-art Digital Elevation Model (DEM). The DEM merged the latest LiDAR and other data surveys of North Carolina’s coastal counties and available bathymetric datasets. From the DEM, the numerical model grid topography and bathymetry were derived. Another component of the system was the combination of advanced numerical models for storm surge, oceanic and near-shore wave fields, and tropical cyclone wind fields to create a flexible software framework on RENCI’s high- performance computer systems. Other vital components included the development of the necessary hurricane parameter representations through application of the Joint Probability Method (JPM) and post-processing statistical methods for derivation of return periods from the computational results and JPM statistics.

This document describes the development of version 2.4 of the DEM and vertical datum analysis, numerical model grid generation, tropical cyclone statistical development, and the archival strategy of the computational results.