Coastal erosion mapping using 3D photogrammetry
Coastal erosion is the wearing away of land along the shoreline due to the natural removal of beach or dune sediments caused by wave action, wave and tidal currents, high winds, drainage and other human-induced causes of erosion . Rising sea levels, more frequent storms and cyclones are also increasing coastal erosion and are putting infrastructures, properties and people at risk.
About 80% of the Australian population lives near the coast and most Australian coastal councils are developing or already have management plans to understand short-term shoreline changes and long-term coastal erosion to ensure that new developments are not in hazards zone now and in the future.
Multi-temporal high resolution aerial imagery and digital elevation models are very useful tools to monitor short-term and long-term changes in the coastline.
With an increasing number of sever storms, high tide levels, wind and wave forces push water up against the coast and can have very serious impact due to abnormally high tide causing temporary inundation of land.
The two aerial photographs below show part of the coastline in Nightciff, NT which is particularly dynamic and erosion prone area. The red and yellow line highlight the variation of the cliff over a period of 5 years.
New geospatial products such as 3D models are now emerging and it is now possible to extract very accurate information of the coastline. The animation below is a virtual fly-through over part of Nighcliff coastline. (courtesy www.fyfe.com.au).
Fluid modeling techniques can be applied to these 3D models to assess the location of sensitive erosion areas and predict land loss in the short-term.