Numerous scientific reports concur that the Dee River is heavily impacted by acid mine drainage from the historic gold and copper mine at Mt Morgan, Central Queensland. The water quality along the Dee River, for 18 km downstream of the mine she to is junction with Fletcher Creek, is characterised by low pH, typically 2.8 to 4.2. With respect to metal concentrations, the Dee River has been described as one of Australia's most polluted rivers. Measurements of pH along the Dee River clearly demonstrated the movement of a slug of acidic water down the river during each of the four flow events between November 2000 and February 2001. Laboratory analysis of water samples collected during November indicated Al, Cu and Zn concentrations orders of magnitude above ANZECC guidelines. Fish kills occurred with each flow event and killed an estimated total of 26,000 fish.