South-East

The South-East, which occupies about 2% of the area f the State and supports 4.5% of the population, is agriculturally one of South Australia's most productive and diverse regions. The name 'Green Triangle' is sometimes given to its southern part. The South-East Statistical Division accounts for about 17% of the State's value of farm output. Softwood timber, pastures and livestock are the bases of the region's productivity, but there are significant areas of vegetable growing near Mount Gambier and Millicent, grape growing north of Penola, and grain production near Bordertown. Of the total value of farm production in 1981, 41% was attributed to sheep and lambs, 24% to beef cattle, 9% to grain, and about 5% to each of dairy cattle, hay and vegetables including potatoes.

In the lower South-East is Australia's largest concentration of Pinus radiata plantations, the basis of an important industry with some thirty saw-milling, woodchipping and cellulose plants. Other industries in the region include an abattoir, dairy factories, a spinning mill, clothing manufacture and a pre-cast concrete plant.

The South-East is characterised by low relief, but there are frequent changes in landscape. Dune ridges of calcareous sands with intervening flats are the most widespread features with, here and there, volcanic hills and ancient granite outcrops. The ridges run nearly parallel to the present coastline for hundreds of kilometres and are remnants of coastal dunes which formed as the sea advanced and retreated during the Quaternary era. These ridges have impeded drainage to the sea, creating extensive inter-dune areas of seasonally inundated freshwater lagoons, lakes and swamps. Some, such as Bool Lagoon are noted for their bird life. A major feature of the coastline is the Coorong, a narrow strip of water behind the coastal line dunes from the River Murray mouth nearly to Kingston.

Between Mount Gambier and Mount Burr lie seventeen volcanic eruptive centres - part of a large volcanic region extending into Victoria and composed of Quaternary and Recent basalt flows, cones and ash. Carbon-14 dating suggests that volcanic activity occurred at Mount Gambier as recently as 4000 years ago. Soils vary across the region from poor grey sandy soils developed on the quartz sand-dunes and high inland plains, to black clays or red brown loams on limestone substrata and rich dark loams on the volcanic ash deposits.

Much of the region is underlain by limestone, producing extensive karst formations of caves and sinkholes. The limestone caves at Naracoorte and Tantanoola attract thousands of visitors annually, while the vast water-filled sinkholes have a reputation of both beauty and danger.

The South-East has South Australia's most favourable rainfall for pastures and timber. Mean annual falls range from 450 mm at Keith to more than 800 mm in the uplands around Mount Burr. The region shares with the southern coast of Victoria, Western Tasmania and the south western tip of Western Australia, Australia's most reliable rainfall and lowest incidence of drought. There are few surface streams, but extensive surface flooding in most winters. The underlying limestone absorbs water copiously, holding large underground resources. The water-supplies of the South-East are second only to the River Murray in their potential significance for the State. The current rate of use for irrigated agriculture can probably be expanded considerably, but careful monitoring and management will be essential to prevent over-drawing and pollution of aquifers from surface activities.

Of the region's population of 59,000 in 1981, 19,880 lived in Mount Gambier. Built beside an extinct volcano, the city draws its water supply from one of three craters, the Blue Lake. It has the largest softwood sawmilling establishment in Australia. Limestone known as Mount Gambier stone is mined in and around the city and has been used extensively for building. Millicent (population 5255) is a centre for forestry, good processing and intensive pastoral farming. Directly south of Mount Gambier is Port MacDonnell (population 682), once a thriving seaport before the advent of the railway, and now home to the State's largest crayfishing fleet.

Pastoral settlement in the South-East began in the early 1840s. Agriculture started about 1850 on the well-drained, fertile volcanic soils around Mount Gambier, and after 1982 in the north around Bordertown and Keith. Naracoorte, surveyed in 1859, was another early nucleus of agricultural growth in a predominantly pastoral region. With 4758 people in 1981 it is the third largest town in the region. Seven kilometres north of Penola (population 1205) is the Coonawarra district where some of Australia's most highly sought-after red table wines are produced. In 1951, there were two wine producers in the area; now there are fifteen. A new grape growing area has recently been developed on former pasture land near Padthaway.

In the north-west of the region is the Coonalpyn Downs District with its townships of Keith, Coonalpyn and Tintinara. With nutrient-deficient soils it was once the Ninety Mile Desert of heath and scrub. Since the 1950s, it has been transformed by the use of trace elements and improved pasture species into a productive mixed farming district producing sheep, cattle, pigs, barley and wheat.