Warragamba Dam
Encyclopedia
Warragamba Dam is the primary water source
for the Australia
n city of Sydney
. It is approximately 65 kilometres (40.4 mi) to the west of Sydney on the Warragamba River
, a tributary of the Hawkesbury River
, and impounds Lake Burragorang
.
wall in the gorge to impound a vast quantity of water.
In 1845, Paweł Edmund Strzelecki drew attention to Warragamba River as a water supply catchment. In 1867, supporters proposed a dam
. Between 1867 and 1946, supporters proposed various schemes before the site and design of the current dam received approval. In 1940, a weir and pumping station known as the Warragamba Emergency Scheme reached completion, just downstream of the main dam site.
In 1943 the Metropolitan Water, Sewerage and Drainage Board invited the geologist William Rowan Browne
to investigate a proposed site. Browne found a more suitable site and continued as geological adviser until completion.
The engineer was Thomas Haynes Upton.
Dam construction began in 1948 and completed in 1960. The resulting dam of the Warragamba River formed Lake Burragorang
, which is one of the largest reservoirs for urban water supply in the world. There is also a hydroelectric power station at the dam that can generate 50 MW.
The dam wall comprises 3,000,000 tonnes (1 200 000 m³) of concrete. It is so large that the engineers had to use two techniques to stop the temperature becoming too hot as the concrete set. One was to add ice to the wet concrete, which was the first application of this technique in Australia. The other was to embed cooling pipes into the concrete and circulate chilled water through the pipes.
Following a 1987 and 1989 re-evaluation of the potential rainfall and flood risks, the government raised the dam wall by 5 metres (16.4 ft) and constructed an auxiliary spillway on the east bank of the dam.
In 2006, the Warragamba Deep Water Storage Recovery Project, part of the NSW Government’s Metropolitan Water Plan, penetrated the base of the dam wall to allow the previously inaccessible lowest water in the reservoir to be available. This new outlet was below the minimum level required for gravity flow, which delivered water from the existing outlets. So, the project constructed a new pumping station downstream of the dam. The new pumping station is within the Emergency Scheme pumping station chamber. This project provided access to 8% more water or approximately six months of extra supply. On 15 April 2006, the project reached a major milestone when it increased the available storage from 1,857,000 Megalitres to 2,027,000 Megalitres. A similar scheme is currently underway at Nepean Dam
.
Other recent major work includes a complete upgrade of the three passenger lifts within the dam wall, an upgrade of the traveling crest crane and a complete upgrade of the four water supply outlets in the valve house, which includes the replacement of the major valves. A full electrical upgrade is currently in advanced planning stage, as is a mechanical upgrade that will address the drum gate and four radial gates.
Although the engineers did not design Warragamba Dam as a flood control measure, it can mitigate flooding by holding floodwaters back while the reservoir fills.
Warragamba Dam was also a popular picnic spot for Sydneysiders but access to the public has been restricted since 1999 due to $240 million of upgrades in that time. It reopened to the public on November 8, 2009.
State Government tried to reduce this risk by implementing water restrictions. Heavy rains between June 2007 and February 2008 restored the dam level to around 67%, despite this Level 3 water restrictions remained in place until midnight Sunday 21 June 2009.
Water supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavours or by individuals, usually via a system of pumps and pipes...
for the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n city of Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
. It is approximately 65 kilometres (40.4 mi) to the west of Sydney on the Warragamba River
Warragamba River
The Warragamba River is a tributary of the Nepean River, and hence of the Hawkesbury River, in New South Wales, Australia. It is best known for being the location of the Warragamba Dam and Lake Burragorang, which form a major part of the water supply to the Sydney region.Prior to the creation of...
, a tributary of the Hawkesbury River
Hawkesbury River
The Hawkesbury River, also known as Deerubbun, is one of the major rivers of the coastal region of New South Wales, Australia. The Hawkesbury River and its tributaries virtually encircle the metropolitan region of Sydney.-Geography:-Course:...
, and impounds Lake Burragorang
Lake Burragorang
Lake Burragorang is the water storage impounded by Warragamba Dam. It collects the waters of the Coxs, Kowmung, Nattai, Wingecarribee, and Wollondilly Rivers. It is the major water storage for Sydney, Australia...
.
Overview
The Warragamba River flows through a gorge that varies in width from 300 metres (984.3 ft) to 600 metres (1,968.5 ft), and is 100 metres (328.1 ft) in depth. This gorge opens out, at the upper end, into a large valley, the Burragorang Valley. This river configuration allows a relatively short but high damDam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
wall in the gorge to impound a vast quantity of water.
In 1845, Paweł Edmund Strzelecki drew attention to Warragamba River as a water supply catchment. In 1867, supporters proposed a dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
. Between 1867 and 1946, supporters proposed various schemes before the site and design of the current dam received approval. In 1940, a weir and pumping station known as the Warragamba Emergency Scheme reached completion, just downstream of the main dam site.
In 1943 the Metropolitan Water, Sewerage and Drainage Board invited the geologist William Rowan Browne
William Rowan Browne
William Rowan Browne was an Australian geologist, author of The Geology of the Commonwealth of Australia.-Early life:Browne was born in Lislea, County Londonderry, Ireland, both parents were school teachers...
to investigate a proposed site. Browne found a more suitable site and continued as geological adviser until completion.
The engineer was Thomas Haynes Upton.
Dam construction began in 1948 and completed in 1960. The resulting dam of the Warragamba River formed Lake Burragorang
Lake Burragorang
Lake Burragorang is the water storage impounded by Warragamba Dam. It collects the waters of the Coxs, Kowmung, Nattai, Wingecarribee, and Wollondilly Rivers. It is the major water storage for Sydney, Australia...
, which is one of the largest reservoirs for urban water supply in the world. There is also a hydroelectric power station at the dam that can generate 50 MW.
The dam wall comprises 3,000,000 tonnes (1 200 000 m³) of concrete. It is so large that the engineers had to use two techniques to stop the temperature becoming too hot as the concrete set. One was to add ice to the wet concrete, which was the first application of this technique in Australia. The other was to embed cooling pipes into the concrete and circulate chilled water through the pipes.
Following a 1987 and 1989 re-evaluation of the potential rainfall and flood risks, the government raised the dam wall by 5 metres (16.4 ft) and constructed an auxiliary spillway on the east bank of the dam.
In 2006, the Warragamba Deep Water Storage Recovery Project, part of the NSW Government’s Metropolitan Water Plan, penetrated the base of the dam wall to allow the previously inaccessible lowest water in the reservoir to be available. This new outlet was below the minimum level required for gravity flow, which delivered water from the existing outlets. So, the project constructed a new pumping station downstream of the dam. The new pumping station is within the Emergency Scheme pumping station chamber. This project provided access to 8% more water or approximately six months of extra supply. On 15 April 2006, the project reached a major milestone when it increased the available storage from 1,857,000 Megalitres to 2,027,000 Megalitres. A similar scheme is currently underway at Nepean Dam
Upper Nepean Scheme
The Upper Nepean Scheme is a series of dams in the catchments of the Cataract, Cordeaux, Avon and Nepean rivers of New South Wales, Australia. The scheme includes four dams and supplies the Macarthur and Illawarra regions, the Wollondilly Shire, and metropolitan Sydney.- History :The Upper Nepean...
.
Other recent major work includes a complete upgrade of the three passenger lifts within the dam wall, an upgrade of the traveling crest crane and a complete upgrade of the four water supply outlets in the valve house, which includes the replacement of the major valves. A full electrical upgrade is currently in advanced planning stage, as is a mechanical upgrade that will address the drum gate and four radial gates.
Although the engineers did not design Warragamba Dam as a flood control measure, it can mitigate flooding by holding floodwaters back while the reservoir fills.
Warragamba Dam was also a popular picnic spot for Sydneysiders but access to the public has been restricted since 1999 due to $240 million of upgrades in that time. It reopened to the public on November 8, 2009.
Catchment
The catchment area is 9050 square kilometres. The areas closest to the lake, making up around 30% of the total catchment, are restricted access special areas. Most of the rest of the catchment consists of cleared farming land and contains large and small towns, which discharge treated sewage into the catchment.Dam level crises and water restrictions
There have been times when drought has seriously depleted the dam. In March 1983, Lake Burragorang's level reached a low of 45.4% of capacity, yet in the mid 90's the dam reached maximum level and the gates were opened. Between 1998 and 2007 the catchment area experienced extremely low rainfall, and on 8 Feb 2007 it recorded an all time low of 32.5% of capacity. If Sydney's water supply runs out it would be a major economic disaster. The New South WalesNew South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
State Government tried to reduce this risk by implementing water restrictions. Heavy rains between June 2007 and February 2008 restored the dam level to around 67%, despite this Level 3 water restrictions remained in place until midnight Sunday 21 June 2009.
Dam statistics
- Height: 142 m
- Length: 351 m
- Thickness at top: 8.5 m
- Thickness at base: 104 m
- Width of central spillway: 94.5 m
- Width of auxiliary spillway (at mouth): 190 m
- Length of auxiliary spillway: 700 m
- Hydro-electric plant capacity: 50 MW
Lake Burragorang statistics
- Available storage (when full): 2,027,000 ML (note: the lowest depths have recently become available for supply)
- Total capacity (when full): 2,031,000 ML
- Surface area: 75 km²
- Length of lake: 52 km
- Length of foreshores: 354 km
- Deepest point: 105 m
- Catchment area: 9051 km²
- Average annual rainfall: 840 mm
See also
- 1998 Sydney water crisis1998 Sydney water crisisThe 1998 Sydney water crisis involved the supposed contamination of Sydney's main water supply, the Warragamba Dam, by the microscopic pathogens cryptosporidium and giardia between July and September 1998....
- Warragamba - township originally built to house dam builders.