Torrens Depression (Environmental Region 7.2)
This region consists of three environmental associations. It is a narrow structural depression which extends southward from Lake Torrens to Spencer Gulf. Under the present climatic regime only during periods of excessive overflow, and lake water reach the Gulf through the depression. Apart from the lake which is fringed by gypsum dunes, the region is a sandy alluvial plain with numerous partly connected lakes and pans. East of Lake Torrens is an extensive field of parallel dunes. Deep red calcareous earths occur on the plain, which carries a low shrubland of various bluebushes and saltbushes. The pans and lakes are fringed by samphires. Mulga shrubland or low open black oak or native pine woodland covers and stabilizers most of the red sand dunes. Background panoramic views are common in the region. The Arcoona plateau in the west and the Flinders Ranges in the east form distant backdrops, but barely provide a vertical element in scenery dominated by the vastness of Lake Torrens. The climate is mild to hot in summer and cool to cold in winter with low and unreliable rainfall and high evaporation throughout the year. Mean annual rainfall ranges from 250 mm in the south to less than 150 mm in the north. Temperatures show high seasonal and diurnal variation. Mean monthly evaporation is very high in summer and exceeds the 90th percentile of monthly rainfall throughout the year. Mean annual evaporation increases from 2200 mm in the south to 3400 mm in the north.
