Modeling Tropical Cyclone Induced Stream Flow in Tar Pamlico River of North Carolina

Abstract

ABSTRACT In order to better understand and simulate large coastal watershed hydrology and hydro-meteorological processes associated with tropical cyclone (TC) induced inland flooding, the Annualized Agricultural Nonpoint source pollution Model (A nn AGNPS) with Muskingum channel routing has been applied to the Tar-pamlico river basin in North Carolina, USA. The study focuses on three major hydro-meteorological processes: 1) large-scale atmospheric environment, 2) watershed hydrological processes and 3) groundwater response. The modeling results indicate that although the AnnAGNPS model can perform well in predicting the total amount of watershed runoff, channel routing is needed to improve the hydrographs of flow discharge during hurricane events. Sensitivity analysis of soil saturated hydrological conductivity ( K s ) indicates that both base flow and event total runoff are sensitive to K s . Base flow increases as K s increases when 0 K s ≤ 15 m/day, but decreases slightly when K s > 15 m/day. Peak runoff exponentially decreases as K s increases. The results also show that without the preceding Hurricane Dennis, the outlet discharge as a result of Hurricane Floyd would have been as much as 37% lower than that caused by the combined Dennis-Floyd effect.