9GEO1: Lesson 2.2 - The Big Dry

Question 1

What is the name of the river basin that constitutes Australia’s agricultural heartland?

Answer 1

Murray-Darling Basin (its one of the flattest catchments on Earth)

Question 2

How much water is available for human use?

Answer 2

Not much (32,500 GL per year on average) – as 94% of rainfall evaporates from waterways / floodplains

Question 3

Climate modelling could ONLY reproduce the strengthening of Australia’s ‘high pressure’ related drought conditions when what factor was included?

Answer 3

Anthropogenic warming due to greenhouse gases – it is thought that they reduce the temperature gradient between the Equator and Poles (reducing energy for mid-latitude storms)

Question 4

How many people depend on the Murray-Darling basin’s water?

Answer 4

3.5 million

Question 5

How much surface water is removed from the river system and how?

Answer 5

42% – either pumped directly from the river to a property or diverted into an irrigation system for urban or agricultural use

Question 6

What was put in place in response to declining river health?

Answer 6

A cap on diversion of water from basin’s river system (by Murray-Darling Ministerial Council)

Question 7

Which human activity is thought to have greatly intensified and prolonged the period of drought over SE Australia?

Answer 7

Land clearance - removal of over 90% of original vegetation since 1800s is thought to contribute to the increased length of drought in any given year.

Question 8

Why has the water diversion cap and subsequent Murray-Darling Basin Plan caused more problems?

Answer 8

It has caused tensions between irrigation-dependent communities, as many illegally extract way above their quota - leaving households downstream particularly vulnerable!