The Ross River Dam is located at the end of Riverway Drive in the city of Townsville, Australia, and is the major water supply for the region. It was constructed by Leighton Holdings in 1971 for the purposes of flood mitigation and water storage. The dam has a capacity of 250 000 megalitres (after the spillway upgrade) and an earth rock embankment 8.35 kilometres (5.19 mi) in length and 27 metres in height (the longest in the southern hemisphere) and occupies a catchment area of 750 km² with a concrete spillway. The dam can hold up to 803 565 ML (344% standard capacity) in flood mitigation. When the dam spills over it flows into the Ross River, Visitors can view the dam from a viewing platform at Ross park. The Ross Dam Pump Station supplies up to 232 megalitres of water to the Douglas Water Treatment Plant, where the water undergoes aeration, sedimentation, rapid sand filtration and chlorination treatment before being pumped to the Reservoir where the water is distributed to Townsville.