How coastal hazards impact coastal development

Coastal hazard boundaries are used in South Australia to guide coastal development and conservation.

Hazard mapping can be found online for the whole South Australian coastline. The hazard mapping informs coastal development in the following ways:

Erosion and shoreline recession

Coastal erosion is a natural phenomenon that can be exacerbated by large storm events, increasing the risk of potential damage to coastal infrastructure and development. With ongoing sea level rise, sandy coasts and dunes will need more and more sand to recover from erosion episodes and fill the gap. This poses a unique management issue for South Australia which must be actively managed in accordance with the Coast Protection Act 1972.

Sand drift

Natural sand drift is an important coastal process, often disturbing older vegetation on dunes and providing opportunities for vegetation regeneration. Rising sea levels and changes to current climatic conditions result in dune systems becoming increasingly unstable. This presents an additional hazard for current and future development within coastal zones.

Coastal flooding and inundation

Coastal flooding and inundation poses a risk to coastal communities and must be considered when developing or managing the coast. To mitigate the risk of flooding to coastal development, the Coast Protection Board has developed policies that recommend specific site and floor levels relative to for each coastal settlement within South Australia. These levels are applied to all development applications received by the Coast Protection Board. The sea level rise allowance used in South Australia is 0.3 metres up to 2050.  Coast Protection Board policy also requires that the development is capable, by reasonably practical means, of being protected or raised to withstand a further 0.7 metres of sea level rise to the year 2100.

Coastal acid sulfate soils

Coastal acid sulfate soils are soils and sediments containing iron sulfides. When exposed to air after drainage or disturbance, these soils produce sulfuric acid, often dissolving and releasing iron, aluminum and heavy metals into the environment from the soils. It can be extremely toxic to plants and animals. Coastal acid sulfate soils may be present in most low-lying coastal regions in South Australia and can be disturbed and exposed by developments that involve drainage, dewatering, excavation and filling. A strategy for dealing with coastal acid sulfate soils has been developed by the Coast Protection Board, in collaboration with the CSIRO's Coastal Acid Sulfate Soils Program.