Victoria Dam (Western Australia) facts for kids
The Victoria Dam is a really important water supply dam that gives water to the city of Perth, Western Australia. It's located in the Darling Scarp area near Lesmurdie, built across a stream called Munday Brook. Two different dams have stood in this spot. The first one was the very first permanent water source for the colony and also the first dam ever built in Western Australia. It lasted for almost 100 years before a new, modern dam took its place.
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The First Victoria Dam (1891–1990)
Quick facts for kids Old Victoria Dam |
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The Old and New Victoria Dams
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| Official name | Victoria Dam |
| Location | Perth, Australia |
| Coordinates | 32°02′25″S 116°04′00″E / 32.04028°S 116.06667°E |
| Opening date | 1 October 1891 |
| Dam and spillways | |
| Type of dam | Arch-gravity dam |
| Impounds | Munday Brook |
| Height | 23 m (75 ft) |
| Length | 220 m (722 ft) |
| Reservoir | |
| Creates | Victoria Reservoir |
| Total capacity | 600 ML (21,000,000 cu ft) |
| Catchment area | 37.2 km2 (14.4 sq mi) |
| Surface area | 0.15 km2 (0.06 sq mi) |
Before the first Victoria Dam was built, people in Perth got their drinking water from wells, natural water sources, and by collecting rainwater. As the populations of Perth and Fremantle grew, people started worrying about water quality. They were concerned about pollution and how to properly get rid of sewage.
For many years, there were lots of ideas for sewage and water systems. However, the local councils and the government couldn't agree on who was responsible. Finally, in 1887, two engineers, Henry John Saunders and James Barratt, put together a big plan for a water supply system.
Planning the Water System
Saunders and Barratt's plan included detailed designs, surveys of the land, and estimates of how much water would flow into the dam. They did all this work even though they weren't guaranteed approval or money. Their plan was to supply water to both Perth and Fremantle.
However, a special committee in the government decided to send the issue back to the local councils. Fremantle refused to be part of the water supply plan. So, after James Barratt left the partnership, Saunders removed Fremantle from the project.
The government then passed a law to allow the project to go ahead. Some private land where the reservoir would be built was taken over by the government for public use.
The site of the proposed reservoir is some 17 miles from Perth, and lies in a hollow of the hills, apparently intended by Nature for some such purpose, surrounded by the jarrah forest. At the lower end the hills approach comparatively close together, where it is proposed to construct the embankment.
Building the Dam
Construction of the first Victoria Dam finished in 1891. This big project also included pipelines that went all the way to Kings Park and a water storage area on Mount Eliza. A private company called the City of Perth Waterworks Company built and ran the whole system. The dam became the first reliable source of water for Perth.
The dam wall was made of concrete. About 1,260 tonnes of cement, which came all the way from England, were used. The wall was designed as a large, curved concrete structure. The finished wall contained about 16,900 cubic meters of concrete.
Water Quality Concerns
Soon after the dam was finished, in 1892, people started to worry about the water getting dirty. The area where the dam collected water was used for grazing cattle and sheep. There were also several timber mill settlements nearby. Raw sewage from the timber mills and animal waste from the livestock were polluting the new water source.
In 1892, some cases of typhoid fever happened at a timber mill in the dam's water collection area. At that time, typhoid fever was becoming more common in Perth. Between 1895 and 1900, there were 4,047 cases and 425 deaths from typhoid fever in Perth. People suspected the water supply was contaminated.
To fix this, the government bought the water system, including the dam, in 1896. In 1897, tests showed that water from the reservoir contained the bacteria that causes typhoid fever. Strict by-laws were then put in place to punish anyone who polluted the water. Also, a special channel was dug to move the polluted Munday Brook water away from the reservoir.
The original dam had two small spillways, which are like overflow channels for water. In 1939, one of these was closed, and the other was made bigger.
Dam Wall Problems
Over time, water started leaking through the dam wall. This leaking caused lime to wash out of the concrete, which made the structure weaker. Efforts to stop the leaking happened in 1912. In 1966, the side of the dam wall facing the water was covered with reinforced concrete to try and reduce more leaking.
However, a review of the dam's design in 1988 found that it wasn't safe enough for big floods or earthquakes. The concrete had also become so weak that it couldn't be repaired. It needed to be replaced.
The New Victoria Dam (1991–Present)
| New Victoria Dam | |
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New Victoria Dam at 30.6% of capacity
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| Official name | Victoria Dam |
| Location | Perth, Australia |
| Coordinates | 32°02′33″S 116°04′02″E / 32.04250°S 116.06722°E |
| Construction began | 23 August 1990 |
| Opening date | 22 November 1991 |
| Dam and spillways | |
| Impounds | Munday Brook |
| Height | 52 m (171 ft) |
| Length | 285 m (935 ft) |
| Reservoir | |
| Creates | Victoria Reservoir |
| Catchment area | 37 km2 (14.3 sq mi) |
| Surface area | 0.77 km2 (0.30 sq mi) |
The decision to build a new Victoria Dam was made in 1989. The old dam stopped being used for water supply on April 3, 1990, and parts of it were taken down. Construction on the new dam started on August 23, 1990.
Modern Construction Methods
The new Victoria Dam wall was built just a little bit upstream from the old one. It was made using a special method called roller-compacted concrete (RCC). This is different from the older ways of pouring large amounts of concrete or using earth to build dams.
This was the first dam in Western Australia to use the RCC method. At the time, it was also the largest dam of its kind built in Australia. Instead of using regular cement in the RCC, they used fly ash from the Muja Coal Power Station. This helped save money and also reduced the heat produced when the concrete hardened.
Because of these modern construction methods, the dam was finished in less than a year after they started digging its foundations. This was half the time it would have taken with older building techniques! The dam was officially opened on November 22, 1991, by Ernie Bridge, who was the Minister for Water Resources at the time.
The new dam provides water to the Perth Hills suburbs of Kalamunda and Lesmurdie. It also helps supply the rest of the Perth metropolitan area when a lot of water is needed. The dam area is not fully open to the public, but people can visit it by walking on special trails.
