From its source in the Victorian Alps, the Goulburn River flows north, snaking through the regional town of Shepparton on its way to meet the Murray on the New South Wales border. Sometimes, the combined waters of both rivers back up along the Murray, travelling for about 80 kilometres to a narrow section of the river called the Barmah Choke, and from there it spills out through the Barmah–Millewa Forest, the world’s greatest, and largest, stand of that classic Australian eucalypt, the river red gum.