Sydney (dpa) – Volunteers filled sandbags and raised levees Wednesday as floodwaters up to 4-kilometres wide rolled down south-east Australia's Murray-Darling river system, picking off town after town in their progress towards south-coast estuaries. More than 15,000 people have been ordered to leave homes that could go under after record-breaking rains caused tributaries to set their own records in a cascade effect. The town of Ivanhoe, for example, received a year's rain – 294 millimeters – in just seven days. Thousands of homes in Wagga Wagga, the region's biggest city, sat in up to a meter of water as evacuees waited in emergency shelters for the all-clear after the Murrumbidgee River peaked at a 40-year high. More than 600 people were told to evacuate Griffith, the center of the region's grape-growing industry 570 kilometers west of Sydney, with warnings that the 25,000 people who live there will be cut off for days. At Nathalia, which is over the New South Wales state border in Victoria, the high-water mark is expected to exceed the 1974 and 1993 flood levels. “The levee's holding up quite well at the moment,” State Emergency Services commander Mark Cattell said. “They're expecting to still have a 30-40 centimeter freeboard.” The Dutch-inspired aluminum levee at Nathalia, erected for the first time this week, is about to get a stern test with floodwaters predicted to peak at 3.1 meters in the next 12 hours. Urana is completely cut off, with supplies to its 1,200 people coming in by helicopter. BM ShortURL: http://goo.gl/yFPBe Tags: Australia, Flood Section: Environment, Latest News, Oceana