Crotty Dam facts for kids
Quick facts for kids Crotty Dam |
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Crotty Dam (at right) aerial shot from the east
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 Location of the Crotty Dam in Tasmania
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| Country | Australia |
| Location | West Coast Tasmania |
| Coordinates | 42°09′35″S 145°37′00″E / 42.15972°S 145.61667°E |
| Purpose | Power |
| Status | Operational |
| Opening date | 1991 |
| Owner(s) | Hydro Tasmania |
| Dam and spillways | |
| Type of dam | Embankment dam |
| Impounds | King River |
| Height | 83 metres (272 ft) |
| Length | 245 metres (804 ft) |
| Width (crest) | 300 millimetres (12 in) |
| Dam volume | 770×103 m3 (27×106 cu ft) |
| Spillways | 1 |
| Spillway type | Controlled and uncontrolled |
| Spillway capacity |
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| Reservoir | |
| Creates | Lake Burbury |
| Total capacity | 1,081,420 ML (38,190×106 cu ft) |
| Active capacity | 1,065,000 ML (37,600×106 cu ft) |
| Catchment area | 559 km2 (216 sq mi) |
| Surface area | 53,250×103 m2 (573.2×106 sq ft) |
| Power station | |
| Name | John Butters Power Station |
| Coordinates | 42°09′21″S 145°32′04″E / 42.15583°S 145.53444°E |
| Operator(s) | Hydro Tasmania |
| Commission date | 1992 |
| Type | Conventional |
| Hydraulic head | 184 metres (604 ft) |
| Turbines | 1 x 144 MW (193,000 hp) Fuji Francis turbine |
| Installed capacity | 144 megawatts (193,000 hp) |
| Capacity factor | 0.9 |
| Annual generation | 576 gigawatt-hours (2,070 TJ) |
The Crotty Dam, also known as the King Dam during its building, is a large rockfill dam built across the King River in Western Tasmania, Australia. It sits between Mount Jukes and Mount Huxley. The dam creates a big lake called Lake Burbury.
This dam was finished in 1991. It was built by Hydro Tasmania to make hydro-electric power. This power is generated at the John Butters Power Station, which is about 8 kilometres (5 miles) away from the dam wall.
Contents
What is the Crotty Dam?
The Crotty Dam is one of two main dams that help control the water for the King River Hydroelectric Power Development. It is located in a deep part of the King River gorge. The dam collects lots of rainwater from the King River area. This water is then sent through a tunnel to the John Butters Power Station.
The dam wall is made from rock and gravel. It is 83 metres (272 feet) high and 245 metres (804 feet) long. When the dam is full, it holds a huge amount of water, about 1,081,420 megalitres. Lake Burbury, the lake behind the dam, covers an area of 53,250 hectares (131,583 acres).
How does the spillway work?
The Crotty Dam has a special part called a spillway. A spillway lets extra water flow out of the dam safely. What makes this spillway unique is where it's built. It's on the dam wall itself, not on the rocky sides of the gorge.
Building a spillway on the dam wall was a big challenge. It was hard to make sure the wall wouldn't move too much. But the engineers used strong gravel in the dam. This helped to keep the wall very stable. The spillway was also designed to adjust if any small movements happened. This design was a first for dams of this size. It means the structure can handle tiny shifts without getting damaged.
The spillway also works with a large valve in a tunnel. This valve can be opened to help release water during very big floods. This keeps the dam safe.
What is the John Butters Power Station?
The water from Lake Burbury travels through a 7-kilometre (4.3-mile) long tunnel. This tunnel goes through Mount Jukes. The water then reaches the John Butters Power Station. This power station is located further down the King River, near where the Queen River joins it.
At the power station, the force of the water spins a large machine called a turbine. This turbine then helps to create electricity.
History of the Dam
The Crotty Dam was built in the 1980s. Its construction began after a different dam project, the Gordon-below-Franklin scheme, was stopped. The Crotty Dam officially started working in 1991. The whole King River Power development was finished by 1992.
The dam is named after James Crotty, who was a prospector. He started a copper mine in the area a long time ago. There used to be a small town called Crotty nearby. This town was covered by the waters of Lake Burbury when the dam was built.
Even in the early 1900s, people thought about building a dam here. The Mount Lyell Mining and Railway Company looked into it. In 1927, a writer named Charles Whitham even suggested the dam would be built one day. He even had a name for the future lake: "Lake Dorothy."
In 2001, a group called Engineers Australia recognized the Crotty Dam. They chose it as one of the 25 dams in Australia with important heritage value. It received a special award for its engineering history.
Images for kids
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Crotty Dam (at right) aerial shot from the east
