Origin of the Barmah-Millewa Forests Approximately 25 000 years ago, an earth movement in the southern Murray-Darling Basin caused a slight uplift of land and created what is now known as the Cadell Tilt Block (sometimes called the Cadell Fault). The edge of the block runs roughly north/south not far from the towns of Deniliquin and Echuca. Although only about 12 metres high it is an important feature in this otherwise flat landscape. It eventually changed the course, pattern and character of the River Murray for some 500 kilometres.
After the uplift occurred, a large shallow lake was created by the dammed Murray and Goulburn rivers. The Murray soon found a new course around the northern side of the Cadell Tilt, creating what is now known as the Edward Wakool River System. For thousands of years the Goulburn River continued to feed the lake but it eventually also broke out to the west. Around 8000 years ago the Murray turned south, breaking through the section between Picnic Point and Barmah, and took over the Goulburn channel downstream of Echuca. The section where the Murray cut through to the Goulburn channel is today known as the Barmah Choke because of its limited capacity to carry flows.
During major floods, large volumes of water are temporarily banked up behind the Barmah Choke. This reduces the height of flood peaks downstream, and floods the former lake area. The regular flooding has created a wetland system now known as the Barmah-Millewa Forest, the largest area of red gum forest in Australia. These forests contain flora and fauna that would be typical of a region which receives two or three times more rainfall than it does. |
