TOTAL WATER LEVEL MODELING IN THE NORTH CAROLINA COASTAL PLAIN: COMPARING ADCIRC AND HEC-RAS

Abstract

The purpose of this Master’s thesis was to develop and compare an ADCIRC and ADCIRC/HEC-RAS paired model for the purpose of total water level forecasting using the Tar River and Pamlico Sound area as a test case. ADCIRC is a 2D hydrodynamic model widely used for coastal storm impact prediction. HEC-RAS is a 1D hydraulic river and stream modeling system. Both models are capable of simulating river systems, but while some of the differences between ADCIRC and HEC-RAS can be intuited simply by studying their underlying equations, a case-study comparison of each model’s ability to accurately and quickly simulate storm impact on a riverine/estuarine system may serve as a valuable tool to forecasters. As part of this project, individual models of the Tar River and Pamlico Sound area in North Carolina were prepared, both in HEC-RAS and in ADCIRC. Pairings of these models were devised to intuit the benefits and drawbacks of using ADCIRC, or pairing ADCIRC with HEC-RAS, to simulate the response of the Tar River and Pamlico Sound during three test events. The results of this study will inform and assist forecasters in selecting and developing similar paired models for coastal river systems across the U.S. and around the globe, as well as improving the body of knowledge about each model’s relative performance in riverine and estuarine areas. This should result in more meaningful and accurate predictions, which will save lives and property in coastal, storm-sensitive riverine areas.