ABSTRACT: Processes in sediment depositon and shoreline changes in the Point Pelee area, Ontario

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

Ever since its formation as a much larger coastal feature some 4000 years ago, Point Pelee has been receding landward (i.e. northward and westward) under the influence of rising lake levels and increasing wave stress. Using some reasonable assumptions, we estimate the average rate of retreat since that time as being in the order of 2.5 m per yr (northward) and 0.25 m per yr (westward). More recent trends inferred from the historical record (reports, surveys and charts) indicate significant change from this overall trend. Average westward recession since 1918 for large portions of the east side of the Point now reaches more than 3 m per yr, and the partially submerged spit south of the Point has been greatly reduced in length. At the same time, however, some areas have remained stable or show a degree of accession over this period. Short-term monitoring of bottom currents in the area are for the most part consistent with the above sediment dispersal patterns, but the energy spectra of the currents suggest that agents such as lake circulation effects (especially those related to seiching) are of greater importance than waves in sediment distribution patterns on the shoal. On the basis of the above information, it is concluded that there is little evidence that commercial dredging in the southernmost areas of the shoal is an important factor in shoreline changes on the Point. However, the dredging operations in the vicinity of the spit itself during the early 1900's, and the proximity of more recent operations (until 1973) to the postulated storage area in the northern areas of the shoal should definitely be considered as adverse factors in explaining the recent trends in shoreline changes at Point Pelee.

Bibliography of Canadian Geomorphology