Regions of South Australia
Limestone Coast is the descripive title of an area that stretches from the border of Victoria and South Australia going towards Adelaide,
Forged over a period of 26 million years by the primal forces of the ocean and the movement of tectonic plates, the Limestone Coast has been perfectly sculpted into a natural holiday playground.
The result? Picturesque port towns such as Kingston SE, Robe and Beachport, where watersports are the order of the day. Impressive volcanic craters and mountain lakes, such as the Blue Lake at Mount Gambier, Port MacDonnell (known for its lighthouse, which started operating in 1859), and the spectacular caving sites at Naracoorte Caves.
These same natural forces created the Coorong National Park, with its sandy coast and lagoons. They also created the 'terra rossa' soils at Coonawarra, which provide the ideal environment for producing world class wines.
It may have taken 26 million years to create the Limestone Coast. But good things are worth the wait.
From the Victoria border to the Younghusband Peninsula this coast has been settled since the 1840s and supports farming, viticulture, forestry and tourism. Towns of the coast include Bordertown, Keith, Millicent, Mount Gambier, Penola, and Naracoorte, the coastal resorts of Beachport, Kingston SE and Robe, and the wine-growing regions of Coonawarra, Padthaway, Wrattonbully and Mount Benson.
Much of the Limestone Coast region is low-lying, and was inundated by sea as recently as 2 million years ago. It had previously also been flooded 15–20 million years ago. The plains are lined by rows of low sandhills parallel to the coast, created at times when the coastline was at that level. Prior to white settlement, much of the land between the sandhills was swamp fed by streams and subject to inundation. A network of drains totalling 1450 km has in the past been constructed to channel the water away through the sandhills to the ocean. Important areas of wetland remain including the lakes and lagoons around the Murray Mouth, where the huge Murray River, by now reduced by draining off into the dry plains of Australia, finally meets the ocean between the Younghusband and the Sir Richard Peninsulas via a series of shallow lagoons including the Coorong, Lake Albert, Lake Alexandrina and Bool Lagoon. Meanwhile areas of upland behind the Limestone Coast include the volcanic craters of Mount Gambier.
The Mediterranean climate of this coast is cool and moist with wet winters.
This Conservation Park is a 543 ha protected area in south-eastern South Australia. It adjoins Discovery Bay on South Australia’s Limestone Coast and conserves a wetland fed by freshwater springs in a karst landscape. It is well-known as a site for cave diving and snorkeling. It is 491 km south-east of Adelaide and 30 km south-east of Mount Gambier. It is close to the border with Victoria.
Piccaninnie Ponds contains three main features of interest to divers. The ‘First Pond’ is an open depression about 10 m deep with a silt floor and much aquatic life, the ‘Chasm’ is a sinkhole with a depth of over 100m, and the ‘Cathedral’ is an enclosed area with limestone formations and a depth of about 35 m. Underwater visibility is excellent and may exceed 40 m. Diving or snorkelling at Piccaninnie Ponds is by permit only.
The park also contains a walking track through coastal woodland to a viewing platform overlooking the wetland
These are a series of three limestone sinkholes on Eight Mile Creek 25 kilometers (16 mi) south of Mount Gambier and 5 kilometers (3 mi) east of Port Macdonnell, South Australia. The ponds are popular with scuba divers, with underwater visibility of up to 80 metres (264 feet) and a large fish population including the endangered golden pygmy perch.
The original inhabitants of the land were Aborigines of the "Boandik" tribe, part of a larger "Bunganditj" clan. The first European identified with the area was Thomas Ewens, whose dog chased a kangaroo into one of the ponds. The land surrounding the ponds was gradually cleared for agriculture and dairy farming and a drainage system built to draw water from the ponds for land sold for soldier settlement programs post-World War II.
In 1978 a trout farm was established utilising the waters flowing through Ewens Ponds. Although the ponds themselves are now part of a conservation park, the farm continues to operate. Water for the farm is drawn from the second pond, and wastewater discharged back into Eight Mile Creek downstream from the pond system.
Each pond is a basin-shaped limestone doline approximately nine metres (30 feet) deep and connected to the others by shallow watercourses called "races". The beds are covered with a fine silt layer and the floor of the third pond also contains a natural shallow cave. The ponds are located in a narrow band of native bush land, surrounded by cleared terrain. The landscape is characteristic of karst topography, shaped by the gradual dissolution of soluble limestone to form hollows and small caves along with numerous large and relatively deep sinkholes (true cenotes).
The ponds contain extremely clear, high quality freshwater in which snorkellers and scuba divers can enjoy the wonder of swimming in a giant 'underwater garden', where the prolific plant life can easily be seen on the far side of each pond, more than 80 metres away in some areas. The clarity of the water also allows sufficient sunlight to penetrate that plant growth on the pond beds can reach up to six metres in height. The ponds are also occasionally affected by outbreaks of blue-green and other algae though testing has found no evidence of health risks. In 2007 the South Australian Environmental Protection Agency suggested the algal blooms may be a result of continued concentrations of soluble nitrogen in both the ponds and the adjoining Eight Mile Creek, arising from infiltration of the groundwater by fertilisers, animal waste or wastewater.
The ponds are one of only three recorded locations for the golden pygmy perch (Nannoperca variegata). Other fish life includes schools of short-finned eel, river blackfish, pouched lampreys, mullet and common galaxias. The ponds are also home to populations of flatworms, freshwater crayfish and mussels, and the larva of the carnivorous caddis fly.
The ponds are owned by the South Australian Government's Department of Water, Land and Biodiversity Conservation and are managed as a conservation park by the Department of Environment and Heritage. Plant and animal species in the ponds are protected and may not be removed.
High underwater visibility, the presence of rare and interesting fish, invertebrates and plants and the ponds' unique photographic potential have made them popular with scuba divers. Of particular interest in these clear waters is the actual observation of photosynthesis - aquatic plants can be seen releasing thin trails of bubbles as they convert sunlight into oxygen. However divers are prohibited from entering caves or crevices on the pond beds and strongly discouraged from disturbing the silt layer as the resulting turbidity may harm plant life. Divers enter at the First Pond, drift with the current through the First Race to the Second Pond, and then continue through the Second Race to the Third Pond before exiting the water via a ladder there. However, some divers (especially snorkellers) occasionally attempt to vigorously swim upstream through the races to return to Ponds One or Two, thereby disturbing the water plants lining the races, and this practice is strongly discouraged by the diving community. The general water temperature of the ponds is around 15 °C (60 °F).