Completed in 1942, the rock–fill dam structure is 32 metres (105 ft) high and 207 metres (679 ft) long. The 71-thousand-cubic-metre (2.5×10^6 cu ft) dam wall holds back the 23,100-megalitre (5.1×10^9 imp gal; 6.1×10^9 US gal) reservoir when at full capacity. From a catchment area of 169 square kilometres (65 sq mi), the dam creates an unnamed reservoir, with a surface area of 301 hectares (740 acres) at a maximum depth of 12.5 metres (41 ft) when at full capacity. The uncontrolled un-gated spillway has a discharge capacity of 680 cubic metres per second (24,000 cu ft/s).[1] The dam is managed by the Toowoomba Region Council.[3]
Cooby Dam's lowest usable storage volume was recorded at 8% in January 2010.[2]
In July 2006, public outcry and a referendum with winning "No" vote rejected plans to place recycled water into Cooby Dam.[citation needed] In 2007, the idea was again resurrected when plans for an advanced water treatment plant to be built near Cooby Dam by the Toowoomba City Council were suggested.[6] The trial would test the re-use of recycled water into Toowoomba's drinking water supply.
In 2008, an emergency bore was used to extract water from the Great Artesian Basin to supplement water supplies for the dam as drought conditions reduced supply to critical levels.[7]
Recreational activities
A stocked impoundment permit is required to fish in the dam.[8][9]
