Rain and run-off
Australia is the driest habitable continent on Earth. This is because it has the smallest amount of run-off of any habitable
continent. (Run-off is rainwater that plants (or the ground itself) do not soak up, and which therefore runs into rivers,
creeks and dams.)
Rainfall and run-off of the world’s continents
Continent
2
Area (’000 km )
Average annual
rainfall (mm)
Annual run-off (mm)
Average run-off as
a percentage of
average rainfall (%)
Africa
30,300
690
260
38
Asia
45,000
600
290
48
Australia
7,700
465
57
12
Europe
9,800
640
250
39
North America
20,700
660
340
52
South America
17,800
1,630
930
57
Source: ABS, Year Book Australia 2002
Australia’s topography is
distinguished by a lack of high
mountain ranges. Much of the
land is flat, allowing for high rates
of evaporation, especially in arid
regions. In fact, only about 30 per
cent of the land mass of Australia
drains straight into the sea; a
large part of this area lies to the
east of the Great Dividing Range.
Recognising that rainwater is
our most precious natural
resource, Australian governments
and communities are increasingly
taking action to conserve water,
and to minimise run-off.
Use the information in
this worksheet and in
the sources listed as
References to complete the following activities.
1.
Australia’s arid interior
Which of the following drainage catchments is Australia’s largest in area?
Gulf of Carpentaria, South-west Coast, Murray–Darling, Western Plateau
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© John Wiley & Sons Australia, Ltd 2005
2005-01-rain.pdf
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2.
Which of the following drainage catchments has the highest distribution of run-off?
North-east Coast, Tasmania, Timor Sea, South-east Coast
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3.
Refer to page 122 of SOSE Alive Geography 2 to find information to justify your answer to question 2.
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4.
Use the data in the table on page 1 of this worksheet to write three meaningful sentences below that draw attention
to the challenges Australia faces now and in the future in conserving rainwater. One has been provided below by
way of example.
Australia receives only about one-quarter of the average annual rainfall received
in South America.
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5.
One of the ways that rainwater run-off can be collected is by building dams and reservoirs. Another is by installing
rainwater tanks around building sites, so that water that falls on roofs is not lost down stormwater drains. Brainstorm
as a class as many other ways as you can think of to reduce run-off so that the saved water can be usefully used.
Reference:
SOSE Alive Geography 2, Chapter 6
© John Wiley & Sons Australia, Ltd 2005
2005-01-rain.pdf
(Page 2 of 2)