General information
This is general information, not planning advice for a particular site. PlanSA shows the zones and overlays on an address, and the council or the Coast Protection Board can say how they apply to a proposal.
Development in South Australia is assessed against the Planning and Design Code, and land inside the Code’s Coastal Areas Overlay counts as coastal land: certain kinds of development there are referred to the Coast Protection Board for direction. The Board can direct against a proposal or set conditions on its approval, for instance where a building would cause erosion and nothing is in place to deal with it.
From address to approval
See what the address carries
Every piece of land in the state has a zone under the Code. Overlays sit on top and carry matters of state interest, coastal ones among them; they take priority over zones and general policies, and can change both the rules and the way an application is assessed. The state’s online system brings the PlanSA portal, the Code and the South Australian Property and Planning Atlas together.
Check whether it is development at all
PlanSA’s approval wizard works this out from the address. Building work, a change of use, new boundaries and advertising signs usually need approval; garden sheds, fences, water tanks and solar panels usually do not. Some protected areas, including land prone to flooding, need approval for every project.
Plan the wastewater with the house
Yorke Peninsula Council asks for the wastewater system to be thought through at the planning stage, and suggests sending its wastewater application at the same time as the development application. Septic systems and the CWMS covers that side.
Lodge it
Since 31 July 2020, applications have gone in online through the state’s planning portal. The council still assesses development, and accepts applications lodged with it directly for an extra processing fee.
The Board is asked
Proposals for new development or a substantial change of land use on coastal land go to the Coast Protection Board for comment. Almost all of its responses are written by DEW’s coastal planning officers under delegation. The Board weighs whether a proposal would harm coastal vegetation, reserves or beaches, and how far it would affect coastal processes, and it tells the planning authority about anything that conflicts with its policies.
The levels the Board looks for
The Board’s policy sets a standard for site and floor levels against coastal flooding. A building site should not be lower than the 1% AEP water level, the level with a 1% chance of being exceeded in any year, plus 0.3 m for sea level rise to 2050, adjusted where land is sinking or rising. Floors of homes and commercial buildings should sit at least 0.25 m above that site level, and the development should be able to be protected or raised against a further 0.7 m of rise. The Code applies the flooding standards town by town, through a Technical and Numeric Variation, so the figure for a given address comes from the Code rather than from a single state number.
The flood level used for a site is more than a tide. The Board’s 1992 explainer said the water level applied to building sites and floors will usually need allowances for wave effects, storm tides and sea level rise, and may also need to account for stormwater held back by high tides, flood control works and future sinking of the land. It describes storm surge as the amount by which the weather pushes a tide above the predicted astronomical tide.
For homes in existing low-lying settlements, the policy says a raised floor may be considered instead of a raised site where the land and buildings around are uniformly low and would not be harmed if the site floods, and where the floor is at least 1.25 m above the 1% AEP level (adjusted for any land movement to 2050), the space underneath stays open so water can flow through, and services such as switchboards, hot water systems and pumps sit above the floor. It names Foul Bay among the settlements where this may be considered, and is frank that raised floors do not remove the long-term hazard.
Worked example
An example only: the 1% AEP water level here is invented, it belongs to no real town, and no allowance is made for land movement. Heights are in metres on the same datum as that level.
| Invented 1% AEP water level | 2.40 |
|---|---|
| Lowest site level: 2.40 + 0.30 | 2.70 |
| Lowest floor of a home: 2.70 + 0.25 | 2.95 |
| The further 0.7 m the site must be able to be protected or raised against: 2.70 + 0.70 | 3.40 |
| Raised-floor route in a low-lying settlement: 2.40 + 1.25 | 3.65 |
Erosion setbacks
The same policy says development should generally stay off sand dunes and away from soft, erodible cliffs. Unless a site is plainly safe from recession and storm erosion, the developer is expected to show, by studies or protection works, that it is. As a general guide, design and setbacks should allow for 100 years of erosion at the site, with 0.3 m of sea level rise by 2050 and a major storm or series of storms taken into account; for major developments that create whole new communities, 200 years. The Board will say whether studies are needed when there is doubt.
Digging in low-lying ground
The Board’s strategy for coastal acid sulfate soils applies where a development would excavate more than 100 m³ or fill more than 500 m³ over an average depth of 0.5 m. Smaller works on an individual property are outside the strategy, though the policy still expects a duty of care in risk areas. Why those soils matter, and how the shoreline itself is managed, is in Coastal erosion and the shoreline.