When most Australians turn on the tap, they expect a continuous supply of safe and pleasant drinking water. They expect it to flow at an acceptable pressure and to be available even in the middle of a drought. They also expect their wastewater will not create a nuisance or public health hazard. Furthermore, they expect to be protected from localised or more substantial flooding. .
During the 19th and particularly the 20th centuries, engineers have designed and built urban water systems to meet these expectations.
The entire area from which a stream or river receives its water is called a catchment. A catchment is a natural drainage area, bounded by sloping ground, hills or mountains, from which water flows to a low point. .
Water Resources and Water Cycle:.
The water cycle begins with rain, which in turn will either fill up dams or fall into catchment areas etc.
Then the water travels to a water treatment plant where it is cycled through until safe and ready for urban use. Once The water has been used in homes in the community it is then passed along as sewage to a sewage treatment plant, and then finally back into our waterways.
Virtually everybody lives in a catchment, which may include hundreds of sub-catchments. What happens in each of the smaller catchments will affect the main catchment. .
That is why catchments are a crucial part of urban water systems.
The quality of the catchment determines the quality of the water harvested from it. Few communities have pristine water sources and the quality of water from most sources is at risk from activities occurring in the catchment. .
Importance of Water:.
More than 70 per cent of the Earth's surface is covered by water. The oceans and seas contain 97 per cent of all the water on the planet. Less than three per cent of the Earth's water resources can be described as freshwater. About 77 per cent of this freshwater is ice, mostly in the polar regions. Most of the rest is ground water.