| Coastal evolution is a complicated process, for it is influenced by various sub-processes and each sub-process such as waves and storms is difficult to well explain and model. To better understand the evolution process, data from several monitoring projects are analyzed with the objective of revealing evolutionary processes. The major focused fields are involved with shoreline changes, coastal geomorphology changes, and wave/storm induced erosion.;This study focuses on the shoreline downdrift of Oregon Inlet, NC. The shoreline data, topography data, wave/tide records have been utilized and become the basis of this study. In order to estimate the coastal changes for the period from 1989 to 2009, a methodology has been created to rectify the wet/dry shoreline, and statistical models have been applied to the shoreline data to characterize the shoreline change pattern and rate. Furthermore, the geomorphology changes alongshore have been coupled with the storm surge and wave runup processes, based on the statistical models. The occurrence probability of dune failure has been estimated by the Logistic Regression model for the prediction purpose. Finally, since all the coastal changes are driven by wave and storm processes, the numerical wave model SWAN have been implemented on order to estimate the nearshore wave climate and attempt correction of shoreline processes.;The results show that the shoreline change near Oregon Inlet has strong temporal correlation and periodicity, and the strength of these characteristics decreases after 2.65 miles southward. Principal Component Analysis revealed the spatial variation of shoreline change is highly concentrated on the first 20 transects and the temporal variation of that mostly exits before 1994 and after 2002. These important findings have been well explained by the beach nourishment projects and storm events. In addition, the shoreline change rate also varies from Oregon Inlet to its south, i.e., the general trend of erosion rate increases from the Oregon Inlet to its south about 2 miles, then decreases for another 2 miles, and increases for the last 2 miles. Furthermore, the geomorphology analysis during a storm suggests that the ratio of effective water level over dune crest height, square root of dune profile area and dune height are the three major factors which mostly determine the occurrence of dune failure. At last, the wave simulations by seasons have explained the seasonality of nearshore waves as well as the spatial variability of wave energy distribution alongshore. The general trend of wave energy is increasing as it goes from the Oregon Inlet to its south, with the exception at about 2 miles south of Oregon Inlet, in which the wave energy has a sharp decrease. Besides, the wave simulation during Hurricane Isabel suggests that waves have higher energy at the east of Oregon Inlet, and have dominant wave direction from the southeast to northwest. Finally, the cross-correlation analysis has shown that about 64% of the shoreline change variance can be explained by the significant wave height and d50. As a result, wave energy and sediment size are two major factors causing shoreline changes during the Hurricane Isabel. |
