Coastal Erosion
The Adelaide metropolitan beaches in particular have been experiencing erosion for decades, as a
result of the natural 40,000-50,000 m3/yr northerly sand transport, exacerbated by dieback of
nearshore seagrass meadows as a consequence of sewage pollution; and further aggravated by some
roads and structured located too close to the shore (1).
Adelaide beaches – eroding & protected by seawalls & nourishment Photo: Andrew Short
Flooding
Sea level rise will also affect coastal hazards such as beach erosion during storms and coastal
flooding. As the sea level rises, severe erosion of beaches during storms will affect areas further
inland, while the depth of floodwaters and the areas affected by flooding will increase due to a
reduced ability to effectively drain low-lying coastal areas (2).
flooding. As the sea level rises, severe erosion of beaches during storms will affect areas further
inland, while the depth of floodwaters and the areas affected by flooding will increase due to a
reduced ability to effectively drain low-lying coastal areas (2).
North Glenelg in storm event Photo: environment.sa.com.au
Sand Dune Drift
A healthy dune system has many benefits; it provides protection from storm erosion, habitat for
indigenous plants and animals and a source of sand for the beaches. Many of our local dune systems
have substantially eroded due to natural coastal processes that produce a northerly movement of sand
together with the extensive development of the Adelaide metropolitan coast (3).
Minda Dunes Photo: City of Holdfast Bay
Coastal Acid Sulfate Soils
Acid sulfate soils underlie large areas of Australia's coastline where the majority of Australians live.
These soils were formed long ago, underwater, when the ocean level was much higher. As the seas
receded, these soils remained and today can be found under low-lying coastal areas like coastal plains,
wetlands and mangroves (4).
The straw-coloured material in this black clay is the mineral Jarosite. Jarosite is evidence that there is oxidised acid sulfate soils. This sample was taken from South Melbourne. Photo: Department of Primary Industries, Victoria
References
1. Coastalwatch, 2009, Impact of Coastal Erosion in Australia, available at http://www.coastalwatch.com/news/article.aspx?articleId=4524&cateId=3&title=Impact%20of%20coastal%20erosion%20in%20Australia, accesed 11th September 2012.
2. Department of Environment, Climate Change and Water NSW, 2009, NSW Sea Level Rise Policy Statement, Syndey South, Australia.
3. City of Holdfast Bay, 2012, Sand Drfit Fencing, available at http://www.holdfast.sa.gov.au/page.aspx?u=1574, accessed 10th September 2012.
4. Department of Primary Industries, 2012, Coastal Acid Sulfate Soils, available at http://vro.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/soil_acid_sulfate_soils, accessed 13th September 2012.
1. Coastalwatch, 2009, Impact of Coastal Erosion in Australia, available at http://www.coastalwatch.com/news/article.aspx?articleId=4524&cateId=3&title=Impact%20of%20coastal%20erosion%20in%20Australia, accesed 11th September 2012.
2. Department of Environment, Climate Change and Water NSW, 2009, NSW Sea Level Rise Policy Statement, Syndey South, Australia.
3. City of Holdfast Bay, 2012, Sand Drfit Fencing, available at http://www.holdfast.sa.gov.au/page.aspx?u=1574, accessed 10th September 2012.
4. Department of Primary Industries, 2012, Coastal Acid Sulfate Soils, available at http://vro.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/soil_acid_sulfate_soils, accessed 13th September 2012.