A closer look at the Maroondah System
The Maroondah Aqueduct, Coranderrk Aqueduct and Maroondah Reservoir are part of an extensive and complex series of water storage and delivery networks, which have helped supply Melbourne with clean running water for more than 150 years. While some sections of this historically significant system have now been decommissioned, many parts are still functional and play an integral role in the everyday supply of water to the city.
What is an aqueduct?
In broad terms, an aqueduct is a channel which transports water from one place to another. In the case of Maroondah and Coranderrk Aqueducts, water is collected in catchments outside of the city of Melbourne, which is then filtered through the soil and into creeks. These creeks supply water for the aqueducts, which in turn, transport water towards the city via reservoirs, pumping stations, siphons and tunnels.
Where does it all start?
Water is first collected in catchment areas to the north-east of Melbourne. These catchments are often rich, densely forested National Parks, where the deep soils act like giant sponges, holding the water and slowly filtering and breaking down impurities. These parks are closed to public access to protect the quality and supply of water.
The catchments then feed water into rivers and creeks. For the Maroondah and Coranderrk Aqueducts, these include the Watts River, Grace Burn and Badger Creek.
What does it do?
Maroondah is the oldest of the two aqueducts. It was completed in 1891 and was historically supplied with water from the Watts River and Graceburn Weir. The water was then transported, by gravity, west for 66km until it met the Yan Yean system at the Junction Basin in Preston.
The aqueduct included 41km of open cement channel (the first time cement had been used in this type of construction in Victoria), eleven tunnels, 15km of inverted syphons and a pipe bridge over the Plenty River to carry water over low areas, gorges and ravines.
The aqueduct was part of the third water scheme to be developed to supply Melbourne, following the Yan Yean and Toorourong Schemes.
Water for the aqueduct is now supplied from Maroondah Reservoir, flowing west until it feeds into the Sugarloaf Reservoir via the Yering Gorge Pumping Station.
Much of the original aqueduct is still functional, helping to supply Melbourne homes with clean water.
Similarly, the Coranderrk Aqueduct transports water to the Silvan Reservoir, as well as to the township of Healesville.
However, in 1908 when the Badger Creek Weir was constructed, water was diverted to Maroondah Aqueduct. During the 1920-30s a new weir, Coranderrk Weir was constructed and water was diverted to the Coranderrk Aqueduct which, in turn, supplied water to the newly constructed Silvan Reservoir.
What is a reservoir?
A reservoir is a large natural or artificial storage of water usually formed by constructing a dam across a river. In this case, Maroondah Reservoir is constructed on the Watts River and feeds the Maroondah Aqueduct for distribution into the water supply system.
How does a reservoir work?
Maroondah Reservoir was constructed in the 1920s to increase the storage volume available to supply the city of Melbourne via the Maroondah Aqueduct. On completion in 1927, the reservoir submerged the Watts River Weir which had previously fed water into the aqueduct.
The dam wall sits an impressive 40 metres high, and serves as a barrier, helping to raise the water level to create the reservoir. The wall is actually an arched concrete gravity dam, which helps ensure the wall is able to withstand the force of the upstream water pressure. The reservoir itself has a capacity to hold up to 22,179 megalitres of water.
A great place to visit
The park area that surrounds the base of the dam wall was constructed in the period directly following the wall's completion. This parkland was made for the enjoyment of the general public and is still considered one of the most significant designed landscapes in the state. Covering an area of approximately 2ha, the park is made up of manicured gardens and includes a vast array of formal plantings, mainly of exotic trees.
The Maroondah Aqueduct, Coranderrk Aqueduct and Maroondah Reservoir are just three of elements of a vast network of water supply helping to deliver clean water to Melbourne homes and businesses.
Various areas within Maroondah Aqueduct, Coranderrk Aqueduct and Maroondah Reservoir are open to the public, and offer enthusiasts places for picnics and waking.