Warragamba Dam facts for kids

Quick facts for kids Warragamba Dam
Warragamba Dam wall
Location of the Warragamba Dam in New South Wales
Country	Australia
Location	Warragamba, New South Wales
Coordinates	33°52′59″S 150°35′44″E / 33.88306°S 150.59556°E / -33.88306; 150.59556
Purpose	Potable water supply
Status	Operational
Construction began	1948; 77 years ago (1948)
Opening date	14 October 1960; 64 years ago (1960-10-14)
Owner(s)	WaterNSW
Dam and spillways
Type of dam	Gravity dam
Impounds	Warragamba River
Height	142 m (466 ft)
Length	351 m (1,152 ft)
Width (base)	104 m (341 ft)
Dam volume	3,000,000 tonnes (3,300,000 short tons; 3,000,000 long tons)
Spillways	Two
Spillway type	Controlled chute spillways with five crest gates and a central drum; automatic operation
Reservoir
Creates	Lake Burragorang
Total capacity	2,031 GL (4.47×1011 imp gal; 5.37×1011 US gal)
Catchment area	9,051 km2 (3,495 sq mi)
Surface area	75 km2 (29 sq mi)
Maximum length	52 km (32 mi)
Maximum water depth	105 m (344 ft)
Normal elevation	180 m (590 ft)
Power station
Operator(s)	Eraring Energy
Commission date	1959; 66 years ago (1959)
Type	Conventional
Turbines	1
Installed capacity	50 MW
Website at WaterNSW
New South Wales Heritage Register
Official name	Warragamba Emergency Scheme
Type	State heritage (built)
Designated	18 November 1999; 25 years ago (1999-11-18)
Reference no.	1376
Type	Water Supply Reservoir/ Dam
Category	Utilities - Water
Builders	Metropolitan Water Sewerage and Drainage Board

The Warragamba Dam is a very important dam in New South Wales, Australia. It's located southwest of Sydney and helps supply drinking water to the city. This huge concrete dam creates a large lake called Lake Burragorang, which is Sydney's main water source.

The dam was built between 1948 and 1960. It was a big project to help with Sydney's water problems, especially during World War II. The dam can hold a massive amount of water, about 2,031 gigalitres (that's 2,031,000,000,000 litres!). The lake covers about 75 square kilometres.

The Warragamba Dam is owned by WaterNSW, a government agency. It's also listed on the New South Wales State Heritage Register, which means it's a special historical site. Sometimes, during droughts, the dam's water level can get very low. But it can also overflow after heavy rains, which is a big event!

History of Warragamba Dam

The area where Warragamba Dam now stands was once the traditional land of the Gundungurra people. Early European settlers were drawn to the fertile river flats of the Burragorang Valley. They started farming and mining there.

As early as 1845, people thought about using the Warragamba River for Sydney's water supply. Over the years, many plans were suggested. The Gundungurra people tried to keep their lands, and some areas were set aside as Aboriginal Reserves. However, these reserves were later taken away. Many traditional owners still stayed, quietly refusing to leave their homelands.

In 1910, an engineer named Ernest de Burgh suggested building a dam on the Warragamba River. His detailed plans were later taken over by the Metropolitan Water and Sewerage and Drainage Board.

Building the Emergency Scheme

In 1940, a smaller project called the Warragamba Emergency Scheme was finished. This included a weir (a small dam) and a water pumping station downstream from where the main dam would be. This scheme was an important first step in getting water from the Warragamba River. Many workers were involved, and the buildings they used were designed to become homes for future dam staff.

Constructing the Main Dam (1948–1960)

The main Warragamba Dam was built between 1948 and 1960. Geologists helped find the best spot for the dam in a deep gorge that opens into the wide Burragorang Valley. This shape was perfect for holding a huge amount of water with a relatively short but tall dam wall.

The dam wall is made of a massive amount of concrete. Engineers had to use special methods to cool the concrete as it set, like adding ice and circulating chilled water through pipes. This helped the concrete cool down in months, instead of the 100 years it would have taken naturally!

Dam Features and Upgrades

The Warragamba Dam collects water from several rivers, including the Coxs, Kowmung, Nattai, Wingecarribee, Wollondilly, and Warragamba rivers. The lake it forms, Lake Burragorang, is one of the largest reservoirs in the world for city water supply.

Spillways: Releasing Water Safely

Warragamba Dam spillway gates

The dam has a main spillway with five gates. These gates open automatically when the dam is full, or they can be opened by hand. This allows excess water to flow out safely. There's also an auxiliary (extra) spillway. This one has "fuse plugs" that are designed to wash away in a very big flood, helping to release even more water.

After studies in the late 1980s, the dam wall was made 5 metres taller, and the auxiliary spillway was added. This was done to help the dam handle extreme flood events better.

Power Generation

The dam also has a hydroelectric power station that can make 50 MW of electricity. However, the water levels are rarely high enough for it to operate often.

Modern Upgrades

In 2006, the Warragamba Deep Water Storage Recovery Project allowed access to water at the very bottom of the reservoir. This meant Sydney had access to about eight percent more water, which is like six months of extra supply!

Other recent upgrades include improving the lifts inside the dam wall and updating the water supply outlets.

Plans to Raise the Dam Wall

Since 2017, there have been plans to raise the dam wall by up to 17 metres. The idea is to protect people and property in the areas downstream from major floods. By holding back more floodwaters, it could reduce the need for urgent evacuations.

However, there are concerns about how this might affect over 50 important Aboriginal heritage sites and parts of a World Heritage Site that would be flooded. This area is also home to rare animals like the critically endangered regent honeyeater, koalas, and greater gliders.

In 2020, the New South Wales Government was asked to re-do their studies on Indigenous heritage. There were worries that the concerns of the Gundungurra and other traditional owners had not been fully addressed.

Water Levels and Restrictions

The dam's water level can change a lot. In March 1983, it was very low at 45.4% full. But by the mid-1990s, it was completely full and overflowing!

Between 1998 and 2007, there was very little rain, and the dam reached its lowest level ever recorded: 32.5% in February 2007. To help with this, the government brought in water restrictions and built a desalination plant at Kurnell to turn seawater into drinking water.

Heavy rains in 2007 and 2008 helped fill the dam back up to about 67%. In March 2012, the dam overflowed for the first time in 14 years due to lots of rain. It also reached full capacity again in August 2020.

Dam Statistics

Visiting the Dam

Warragamba Dam used to be a popular picnic spot for people from Sydney. Access was limited for a while due to upgrades, but it reopened to the public in November 2009. You can sometimes visit the dam wall and terrace gardens on weekends and public holidays.

Heritage Importance

The Warragamba Emergency Scheme is important because it shows how engineers responded to Sydney's water shortage during World War II. It was the first step in using the Warragamba River for water. The buildings and structures from this scheme are great examples of civil engineering from that time.

The Warragamba Emergency Scheme was added to the New South Wales State Heritage Register in 1999. This means it's a rare and important part of New South Wales's history and science.