A statistical analysis of the controls on shoreline erosion rates, Lake Ontario

Recession of the cohesive shorelines of the Great Lakes is controlled by the complex interaction of a number of processes and factors, including the magnitude of wave energy reaching the shoreline, sediment supply and beach sediment budget, and several morphological and geotechnical properties of the bluff and bluff sediments. The difficulties of making measurements of processes in this environment have meant that progress in determining the role and relative significance of the controlling variables has been slow. In this study linear multiple regression is used to determine the degree and nature of the relationship between shoreline recession rates and four predictor variables for a section of shoreline at the south-west end of Lake Ontario. The variables used are wave energy, sediment availability, potential longshore sediment transport rate and bluff height. The data are derived from a previous study of littoral drift and sediment budget modelling within the study area and consist of values for each variable for points spaced at 200 m intervals along a 14 km shoreline length. The four variables, account for 72% of the variability in shoreline recession rates. The success of the model in this application is attributable in part to the uniformity of the geotechnical properties of the cohesive sediments within the study area and to the level of detail provided by modelling of wave refraction and littoral drift.