Catchment Area
The Sydney Catchment Authority drinking water catchments cover over 16,000 square kilometres. Nearly 60 per cent of the land is privately owned and 25 per cent is national park. Sydney relies on the Warragamba, Upper Nepean, Blue Mountains, Shoalhaven, and Woronora river systems to supply their drinking water. These catchments extend from north of Lithgow in the upper Blue Mountains, to the source of the Shoalhaven River near Cooma in the south - and from Woronora in the east to the source of the Wollondilly River west of Crookwell.
Warragamba Dam is Sydney’s principle water storage dam. It is located 60 km west of Sydney in a narrow gorge on the Warragamba River and is one of the largest domestic water supply dams in the world. It has a capacity 2 million mega litres, almost 4 times the capacity of Sydney harbour. The catchment area of Warragamba dam is approximately nine thousand square kilometres. Water is delivered from Warragamba dam to the Prospect Water Filtration.
Possible sources of contamination in this catchment
Intensive agriculture such as market gardening is a potential source of contamination within the catchment especially the use of pesticides and fertiliser.
Beef production has the potential to contaminate water sources if manure enters the waterways, especially if stock have direct access to water courses. This can result in bank erosion and faecal matter being directly deposited into the water. Water quality may be affected and have high measurements of nutrient concentrations and suspended solids.
Land cultivation for agriculture can increase the sediments entering the waterways as erosion occurs. Land clearing to establish mining, infrastructure, processing, stockpiling and storage of waste materials leads to erosion and transportation of sediment to waterways.
Less than 1% of land in the Sydney catchment area is used for urban development. Sewage and stormwater runoff are sources of possible water contaminants such as...