A FLOOD CLIMATOLOGY OF THE LOWER ROANOKE RIVER BASIN IN NORTH-CAROLINA

Flooding processes in the lower Roanoke River Basin (RRB) exert a stro ng control on the distribution of forest-community types and geomorphi c landforms across the floodplain. Since the early 1950s, the flow of the river has become regulated as a series of dams have been built ups tream of the lower RRB. As a consequence, the variability of the disch arge has been reduced dramatically; extended periods of low-magnitude flooding now replace the transient high-magnitude floods that characte rized the unregulated regime. In this study, regression analysis is us ed to model long-term trends in the unregulated flow regime (i.e., no dams upstream). Comparisons of the observed flows before damming with the predicted flows after damming (i.e., no flow regulation) provide e stimates of flow a iterations resulting from climate change. By compar ing the modeled flows with observed flows after damming, the impacts o f damming on the river are isolated (i.e., climate held constant). The constructed empirical model indicates that the magnitude and frequenc y of flooding on the unregulated stream has increased dramatically in the spring, but has decreased in the summer.