Our western boundary is almost nine kilometres of coastline. It is an attraction for thousands of tourists who visit our clean, sandy beaches all year round.
Due to the natural processes of wind and waves, our coastal environment is highly dynamic, naturally erosive, and ever-changing. Our coastline, like all of Adelaide's metropolitan beaches, is managed to counter the impacts that threaten to damage it.
Seagrass beds are found just out from our beaches’ low watermark and provide important habitat and food sources for marine organisms such as fish. Their root systems also play an important part in anchoring the sand and preventing erosion.
The seagrass beds along our coastline are under threat from pollution and physical disturbance, including wastewater, stormwater, shipping, and boating.
The responsibility for the management of our beaches is shared between Council and the State Government, as part of the Adelaide Living Beaches strategy, implemented by the Coast Protection Board, which is part of the Department of Environment and Water.
Sand naturally moves northwards by longshore drift and, prior to European settlement, the beaches were naturally replenished from the dunes, and therefore sand movement could continue almost indefinitely. However, development along our coast has resulted in large quantities of the sand supply either being 'locked up' or removed from the beach system, preventing natural replenishment.
As a result, natural processes and coastal storms have eroded beach width, and without artificial replenishment, sand will continue to erode away, exposing the underlying hard rocks and clays.
To counteract this, sand is pumped from areas where it naturally builds up (Glenelg) and is deposited at 16 key locations between Kingston Park and Glenelg. In order to maintain sandy beaches, sand replenishment activities will need to continue. It is an expensive exercise, especially due to dwindling local sand sources, loss of seagrass, rising sea level, and the need to bypass sand around the harbors at Glenelg and West Beach.
A healthy dune system has many benefits, from protecting against storm erosion to providing habitats for indigenous plants and animals, and as a source of sand for the beaches.
We are using sand-drift fencing to help recreate and protect dune systems from erosion, by trapping wind-blown sand in the vicinity of the fence where natural vegetation is not sufficient to do so effectively. However, such fencing does not completely prevent natural erosion – it merely slows down the movement of our fine dune sand.
We have three main dune areas beside our beaches: the Brighton to Seacliff dunes, the Glenelg dunes, and the remnant Minda dunes at Somerton Park.
These dune systems are an important asset to the area providing protection from storm and tide impacts, and a habitat for birds, reptiles, and insects. Before extensive coastal development in the 19th and 20th centuries, the original dunes were up to 20 m high and went inland 200 - 300 metres. They were an important source of food and shelter for the traditional owners, the Kaurna people.
Since the late 1990s, Council has conducted revegetation and restoration projects with the help of local residents, primary schools, and volunteer conservation groups.
The Minda dunes are important remnants, one of only two original dune systems along the entire Adelaide coastline. During 2018-19, council, in partnership with the State Government and Minda Inc., was able to undertake a significant amount of biodiversity works to improve the Minda dunes. In particular, removing a large number of woody weeds such as boxthorn, athel pine, and olives, followed by planting 10,000 native dune plants will transform the dunes into high-quality dune habitat.
Council has recently developed a Holdfast Bay Dunes Biodiversity Action Plan 2019-2024. The plan captures important information about the current state of our dunes, as well as making prioritised recommendations to improve the biodiversity over a 5 year period.
Much of our coastline has been developed and therefore altered since European settlement. However, areas of significant remnant vegetation still exist in pockets along the coast.
The plant communities feature a diverse variety of plant species – most of which are highly adapted to survive in the soil and climatic conditions characteristic of our seaside environment. They are particularly tolerant to salt, wind, infertile soils, and hot, dry conditions.
Both on land and in the water, these areas of native vegetation form important habitats for wildlife. They play an important role in stabilising marine sediments and dunes and forming a protective buffer between the land and the sea.
We strongly encourage the use of local indigenous plants in creating water-wise gardens, as they are perfectly suited to our soil and climate; thrive without additional water; don't require fertilizers or pesticides; and provide a natural habitat for indigenous birds, fauna, insects, and reptiles. For more information about environmentally-friendly gardening, see our Green Living Gardens section.
A weed is any plant that grows where it is not wanted. Unfortunately, introduced species form a significant proportion of our coastal vegetation, and not only include plants that have been introduced from overseas, but also native species from other regions of Australia.
Weeds affect native plants by successfully overpowering and replacing them and, in some cases, by forming conditions that prevent indigenous species from establishing around them.
Reducing the damage caused by weeds, and protecting our coastal environment and its biodiversity is a key priority for us, and our specialist teams actively control unwanted plants throughout our reserves and foreshore regions.