Margery F. Overton
Published: 1999
Total Pages: 88
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The purpose of this study is to determine surge hydrographs which may be used in the analysis of proposed and existing highway structures along Albemarle-Pamlico Sounds. Historical data for tropical storms over the period 1886-1996 were collected and analyzed to identify storms proximate to the project study area. Application of the process models (CE Wind Model and ADCIRC Model) and statistical models (EST) resulted in predicted surge values at 25, 50 and 100 year return periods. These peaks were then incorporated into synthetic time series used to characterize the shape of the design hydrograph. The results of the surge modeling suggest that the simple exponential form of the hydrograph, recommended by the FHWA pooled fund study 'Development of Hydraulic Computer Models to Analyze Tidal and Coastal Stream Hydraulic Conditions and Highway Structures', may be inadequate to characterize stations which experience periods of negative surge. An empirical approach based on a damped sine wave was developed as an alternative. The recommended procedure for implementing the results of the study suggests that both types of hydrographs be modeled, with design parameters based on the worst-case conditions.