Creekcare

Water Cycle

Water is essential for all life on earth. About three billion years ago life began as small microscopic marine organisms. Nearly 300 million years ago primitive amphibians crawled out of their watery home on to dry land. Humans appeared about 1 million years ago. Since then our numbers have grown enormously and our way of life has had profound consequences for the water cycle, particularly in urban areas.

The Natural Water Cycle

Drawing of the Water Cycle The water cycle begins with water being evaporated by the sun mainly from the sea, which becomes vapour and forms into clouds. Some of the cloudy vapour blows inland where it falls as rain before eventually flowing back to the sea.

rain, hail, snow and fogs
interception and evaporation from plant surfaces
depression storage(puddles)
runoff
soil infiltration and percolation
transpiration and evaporation
water table and ground water
creeks, brooks, rivers and lakes
swamps, wetlands, billabongs and anabranches
oceans, seas, harbours, bays and gulfs

Where does the rain go?		native bush	urban area

In the bush most rain is transpired by plants back into the atmosphere. Where we live in cities, most rain goes down the drain making bigger floods. A large proportion of pollution occurs in flood waters.	interception by plant leaves	15%

	runoff	15%	90%

	transpiration and evaporation	60%	10%

	percolation to water table and ground water	10%

Creekcare

Water Cycle

The Natural Water Cycle

rain, hail, snow and fogs

interception and evaporation from plant surfaces

depression storage(puddles)

runoff

soil infiltration and percolation

transpiration and evaporation

water table and ground water

creeks, brooks, rivers and lakes

swamps, wetlands, billabongs and anabranches

oceans, seas, harbours, bays and gulfs

Where does the rain go?

native bush

urban area