Wivenhoe Dam is a dam built across the Brisbane River that creates the artificial Lake Wivenhoe. The dam is located about 80 kilometres by road from the centre of Brisbane, Queensland, Australia.
The dam holds a volume of water two and a half times the water in Sydney Harbour. The primary purpose of the dam is to provide a water storage for south-eastern Queensland as well as extra storage for mitigation of periodic flooding of the Brisbane River. The lake also forms part of the water storages for the Wivenhoe Power Station.
Purpose
Wivenhoe Dam consists of an earth and rock embankment 2.3 kilometres long and 50 metres high. It has a concrete spillway section on which five steel crest gates are installed. The gates, at 12 metres wide and 16.6 metres high, are amongst the largest of their type in the world.
The dam has a total storage capacity of 2.61 km³, of which 1.16 km³ is used for urban water storage. 200 properties were acquired to provide the 337.50 square kilometres of land required for the dam. The catchment area is 5,554 square kilometres.
The dam holds twice as much water as Sydney Harbour and is about seven times bigger than Hinze Dam at the Gold Coast. Wivenhoe Dam does contribute to the Gold Coast's water supply.
Key facts
As of 2007, the reservoir has diminished in the midst of Queensland's severe drought, and the original path of the Brisbane River has become increasingly visible. Pockets of isolated water have begun to form and an island has revealed itself towards the lake's centre.
A previously unseen sandbar emerged from the waters of the lake towards the end of 2006. It presented a high risk that the power stations' water supply could prematuraly cease the supply of water from the Caboonbah pumping station.
Drought
Source
Average annual rainfall: 940 mm
Capacity – water supply: 1 165 000 ML
Capacity – flood storage: 1 450 000 ML
Submerged area at full supply level: 109.4 km²
Stream Bed Level at Structure (AHD): 23 m
Embankment or Crest Level (AHD): 79 m
Type of Structure: Embankment (4 000 000 m³) and Concrete (140 000 m³)
Year of Completion: 1985
Length of Wall: 2 300 m
Spillway Gates: 5 x 12.0 m x 16.6 m
Regulator Valves: 2 x 1.5 m diameter
Average Evaporation (mm/year): 1 872
Hydro Electric Station/dam structure: 4.5 megawatts
Design: Queensland Water Resources Commission
