Open File 012B/0705

Coastal Erosion in St. George’s Bay, Western Newfoundland

M. Irvine

St. John’s, Newfoundland, August, 2019

Abstract

The coast of St. George’s Bay, western Newfoundland, is vulnerable to erosion as shown by results from field studies conducted by the Geological Survey of Newfoundland and Labrador (GSNL) between 2011 and 2016, and earlier by the Geological Survey of Canada (GSC) between 1991 and 2000. Real Time Kinematic (RTK) topographic survey data were collected by the GSC between 1994 and 2000 at five monitoring sites, and RTK and Unmanned Aerial Vehicle (UAV) data were collected by GSNL between 2011 and 2016 at ten monitoring sites.

Coastal erosion monitoring quantify rates of coastal erosion of the cliffs and changes in beach profiles, assess the longer term effects of climate change, and determine factors affecting the variable rates of coastal erosion. Planners, landowners and other stakeholders can use the published results allowing for better land-use management practices.

The mean annual rate of erosion at St. David’s is 59 cm, and 2 cm a year at Port au Port. Beach width and cliff exposure to waves appear to be the dominant factors resulting in higher rates of erosion, and where waves do not regularly reach the cliff base, groundwater flow is likely having the most impact. Changes in the climate will affect coastal erosion along the coastline of St. George’s Bay. Factors such as rising sea levels, and increases in the frequency and severity of storms will intensify wave erosion at the base of cliffs.

This research is part of a systematic, long-term study of coastal environments around Newfoundland and Labrador. Repeated UAV surveys are planned at existing monitoring sites. Data analysis will allow for a better determination of coastal erosion and an assessment of geomorphic variables affecting coastal erosion.

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