General information
This is general information, not an assessment of any property’s risk. The Department for Environment and Water and its Coast Protection Board publish the state’s coastal hazard policies and mapping.
Coastal erosion happens naturally in South Australia and large storms make it worse. The Department for Environment and Water (DEW) says that as the sea keeps rising, sandy beaches and dunes need more and more sand to recover from each bout of erosion. The Coast Protection Board, formed in 1972 under the Coast Protection Act, is the state body charged with protecting and restoring the coast.
Four hazards on the state’s list
DEW uses mapped hazard boundaries, available online for the whole South Australian coastline through its NatureMaps service, to guide building and conservation near the sea. It describes four hazards.
- Erosion and shoreline recession
- The coast wearing back, sped up by storms. DEW says the issue must be actively managed under the Coast Protection Act 1972.
- Sand drift
- A natural process that disturbs older dune plants and gives new ones room to grow. With rising seas and a changing climate, DEW says dunes are becoming less stable, a further hazard for anything built nearby.
- Coastal flooding and inundation
- The sea coming over low land. The Board has set recommended site and floor levels for each coastal settlement, and applies them to every development application it receives.
- Coastal acid sulfate soils
- Soils holding iron sulfides that form sulfuric acid once drained or dug up, releasing metals that can be very toxic to plants and animals. DEW says they may lie under most low-lying coastal land in the state.
What the Coast Protection Board does
The Coast Protection Act 1972 gives the Board a set of functions, which DEW lists in plain terms.
- Protect the coast from erosion, damage, deterioration, pollution and misuse, and restore parts already harmed.
- Improve the coast for the people who use it, and look after the coastal facilities in its care.
- Carry out or join research into protecting, restoring and developing the coast, and report to the Minister where required.
To do that, the Board can carry out works and remove sand, acquire coastal land with the Minister’s approval, and enter land. It meets every six to eight weeks. Its policy document quotes the Act’s definition of the coast, which includes land above and within one hundred metres of the mean high water mark.
The allowance for a rising sea
The figure the state plans around has changed as the science has. In date order:
- Early 1980s
South Australia applied an allowance of 0.15 m of sea level rise.
- May 1991
The state government endorsed the policies the Board had recommended on sea level rise and on standards for new coastal development.
- January 1992
The Board’s explainer, Coastline No. 26, set out an allowance of 0.3 m to the year 2050 in place of the old 0.15 m, and gave a possible range for 2100 of 0.35 m to 1.10 m, with a midrange figure of 0.65 m.
- Today
DEW states the allowance as 0.3 m to 2050, with new development able to be protected or raised against a further 0.7 m by 2100. It cites IPCC modelling of average global sea level rising by about 3.3 mm a year in recent decades.
The land can move too. The 1992 explainer said land subsidence is very small along most of the South Australian coast and can be ignored, but that rates of 1 to 2 mm a year occur in some places, the Adelaide coast among them, and that uplift was known only in the Upper Spencer Gulf.
DEW expects a higher sea to mean more erosion of dunes and loss of beaches, and changes to where beaches build up or wear away, because waves strike the shore at a different angle.
On the peninsula
Yorke Peninsula Council calls its coastline a sensitive system and guides the management of the coastal land in its care through a Coastal Management Strategy, published in three stretches: Hickeys Point to the Corny Point lighthouse, Corny Point to the council border at The Gap, and the border at Federation Park back to Hickeys Point. It notes that its beaches have many kinds of tenure, from council and Crown land to Indigenous Protected Areas and private land. The strategy aims to improve coastal access and recreation while protecting landscape, heritage and biodiversity, and the council uses it to set priorities and seek funding for works on its own coastal land and infrastructure.
DEW’s wider warning is that the state’s coastline is losing its natural resilience, leaving beaches less able to protect themselves from storms. The Coast Protection Board’s grants have reached this coast in recent rounds.
| Round | Project | Grant |
|---|---|---|
| 2024–25 | Foul Bay, Mud Alley defence design | $63,000 |
| 2024–25 | Port Vincent, Marine Parade foreshore design | $30,000 |
| 2025–26 | Coastal hazards at Mud Alley, Foul Bay | $127,500 |
The 2026–27 round offers up to $1 million to coastal councils, with expressions of interest open from 6 to 20 October 2026. The Board says it will favour projects that carry out actions from councils’ coastal hazard adaptation plans.
What all this means for a house is the subject of Building near the coast, which follows the Board’s levels and setbacks into an application.