Murray Lakes (Environmental Region 2.1)
This region consists of five environmental associations. It is dominated by Lakes Alexandrina and Albert which form large depressions in the Murray plain. The Murray River flows into Lake Alexandrina and its waters discharge into the ocean through a narrow breach in the coastal sand bar-dune system. This has been artificially closed by barriers which prevent the inflow of salt water and slow allow the lakes to be flushed when the salinity becomes too high. Small lacustrine plains and swamps with saline cracking clays fringe the lakes and are bordered by undulating calcrete plains covered by extensive sand sheets. Some of the undulations are due to consolidated dune ridges. Unconsolidated dunes with deep sands occur in the east of the region. The samphire and saltbush shrublands of the lacustrine plains and swamps have been degraded through grazing, whilst the native vegetation on the higher ground has been largely replaced by improved pastures. The climate is distinguished by a dry summer and a winter rainfall maximum, with annual totals ranging from 400 mm in the north to 500 mm in the south. Temperatures range from mild to warm in summer and cool to cold in winter.