why does melbourne have such good drinking water
Water supply and sanitation in Australia Some 90% of Melbourne's drinking water comes from uninhabited mountain ash forests high up in the Yarra Ranges east of Melbourne. More than 157,000 hectares has been reserved for the primary purpose of harvesting water. These water supply catchments have been closed to the public for more than 100 years. Melbourne's water supply system is based on the principle that it is better to start with the highest quality source water than having to treat it to reach required standards. According to Melbourne Water, Melbourne is one of only about[weasel words] five cities in the world that has such protected catchments.[14] Water from the forests flows through streams in reservoirs, which provide security of supply for times of drought. One of these reservoirs is formed by the Thomson Dam on the Thomson River located about 130 km east of Melbourne in Gippsland, from where water flows through a 19 km long tunnel through the Great Dividing Range into the Upper Yarra Reservoir and then onto Silvan Reservoir for distribution as drinking water in Melbourne. In recent years, drought has resulted in depletion of much of the water in the reservoir of the Thomson Dam.
Water supply and sanitation in South Africa Total annual water withdrawal was estimated at 12.5 km3 in 2000, of which about 17% was for municipal water use.[6][7] In the northern parts of the country, both surface water and groundwater resources are nearly fully developed and utilised. In the well-watered southeastern regions of the country significant undeveloped and little-used resources exist.[6] The Gauteng area around Johannesburg, which is very water scarce, receives water from various dams in the area such as the Vaal Dam and imports water from the Orange River system through the Lesotho Highlands Water Project, in particular from the Katse Dam.[10] Cape Town receives its drinking water from an extensive system of rivers and dams, including the Berg River Dam.