Once water is treated, the next step is to distribute it throughout town to ensure a reliable supply is available to everyone. This is delivered through a network of pipes, mains and pumping stations and stored in a series of urban water service reservoirs.
Water pipe network
In the ACT, we deliver more than 100 million litres (100,000,000 l) of water each day to ACT residents. Water from the Mount Stromlo and Googong water treatment plants is delivered by bulk supply mains to 47 urban service reservoirs. From here the water is fed into distribution mains to transport it to households.
The size of these pipes in the network are designed to transfer enough water for all the households serviced by the reservoir in a 24 hour period. Pipes can be as thick as 1500mm (1.5 metres) in diameter near the treatment plant. They can be as small as to 100mm in diameter for pipes leading to the smaller reservoirs.
Urban water storage reservoirs
There are 47 primary and secondary service reservoirs in the Canberra water supply system. These reservoirs store water for later distribution to households. Most reservoirs in the ACT are filled from the treatment plant using gravity to help the water flow downhill through the pipes to the reservoirs.
Where reservoirs are too high to be filled by gravity, pump stations are used to move the water. There are 18 pump stations around Canberra that help water reach the higher reservoirs, especially at times of high water use. They help the water network cope with changes in water demand and help manage the water pressure so that water flows out of taps at the speed people expect.
Reservoirs may be above or below ground. Underground tanks are often rectangular with a concrete lining. Above ground reservoirs are often circular tanks made of concrete or steel. Where possible, reservoirs are placed on high ground so that gravity will help provide enough pressure to push the water through the pipes.
All reservoirs have enclosed roofs to prevent contamination from birds, animals and wind-borne debris and they are designed to blend in with the environment.
The service reservoirs provide storage for between 450 ML and 680 ML (or 620 megalitres (ML) and 800ML of water. That's 620,000,000 to 800,000,000 litres of water!). Regular inspections are conducted to ensure there has been no unauthorised entry. There is also a program in place for reservoir cleaning.
The program ensures reservoirs will be cleaned and inspected regularly. Each reservoir is routinely monitored for total coliforms, thermo tolerant coliforms, heterotrophic plate count, temperature and chlorine levels. Treatment of water at the reservoir can be carried out if required.