Jimmys Beach, Post Stephens, NSW. Erosion events like this often occur during storms on coastlines that already have a deficit of sand and are likely retreating (ABC News).
Prepared by Daniel Harris, Beachlab, School of the Environment, The University of Queensland. daniel.harris@uq.edu.au
The steps below are also in the supporting video for guidance. This may be especially helpful for the analysis in Excel.
Aerial imagery is the main approach used to monitor shorelines over the medium- (yearly) to long-term (decadal) since it provides both a large spatial extent and, in some places, a record extends back many decades. Monitoring shoreline position through time provides excellent insights into the medium to long-term trends of progradation and retreat. In natural systems:
If aerial or satellite images are regular enough you may be able to determine seasonal or storm event impacts on the coast. However, adequate aerial images are usually only available once or twice a year at best. Only recently have satellite observations made fortnightly tracking of shorelines possible but this is still in its infancy as a realistic coastal monitoring strategy.
Recently composite yearly satellite images have been used to provide the average annual shoreline position since the mid-1980s around the world. Digital Earth Australia has provided once such data set (since 1988) on an easy to use platform which we will use for this practical (Figure 4.1). This practical will show you how to access the data and perform a basic analysis of long-term coastal change.
Figure 1. The concept of ‘leaky and ‘closed’ sediment compartments. Black arrows indicate sediment pathways, and the compartment are typical examples at the tertiary scale.
Figure 2. Digital Earth Australia Coastlines data map.