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, inclu ding the magnitude of wave energy reaching the shoreline, sediment sup ply and beach sediment budget, and several morphological and geotechni cal properties of the bluff and bluff sediments. The difficulties of m aking measurements of processes in this environment have meant that pr ogress in determining the role and relative significance of the contro lling variables has been slow. In this study linear multiple regressio n is used to determine the degree and nature of the relationship betwe en shoreline recession rates and four predictor variables for a sectio n of shoreline at the south-west end of Lake Ontario. The variables us ed are wave energy, sediment availability, potential longshore sedimen t transport rate and bluff height. The data are derived from a previou s study of littoral drift and sediment budget modelling within the stu dy area and consist of values for each variable for points spaced at 2 00 m intervals along a 14 km shoreline length. The four variables, acc ount for 72% of the variability in shoreline recession rates. The succ ess of the model in this application is attributable in part to the un iformity of the geotechnical properties of the cohesive sediments with in the study area and to the level of detail provided by modelling of wave refraction and littoral drift.