A Changing Coastline: Using GIS to Evaluate the Primary Causes of Increased Coastal Erosion in the Minas Basin, Nova Scotia.

The Minas Basin, Nova Scotia is a semi-enclosed macrotidal bay, home to the world’s highest tides and a dynamic coastline. A diverse array of birds, fish and mammals live in the unique ecosystems of the Basin. The tidal rage in the Minas Basin continues to increase (Greenburg et al, 2012) and with the likely event of significant sea level rise in this century, as well as a predicted increase in storminess (Trenberth et al, 2007), improved understanding the dynamics of the coastline, the movement of sediment and the effects on the surrounding ecosystems is essential. This project used historical aerial photographs from 1964, the early 1990s and 2013 to quantify past erosion rates along the Minas Basin coastline. The use of Geographic Information Systems (GIS) allowed for a detailed and accurate evaluation of the coastal areas undergoing geomorphological changes over these time periods. Erosion rates in the past 20 years were higher than erosion rates in the 30 years before. Erosion rate data were overlain with multiple factors such as bedrock and surficial geology, wind fetch, tidal water levels at landfalls of major storms, salt marsh locations and winter temperature data to determine which of these were associated with higher erosion rates in certain parts of the Basin. These factors were compared also with the observed increase in overall erosion rates over the time periods studied. Determining which factors correlate with the highest rates of erosion will help to improve understanding of the system and to focus mitigation efforts on the most vulnerable coastlines and associated infrastructure.