Salinity– an environmental emergency

Salinity is one of Australia’s greatest
environmental problems. It occurs when too
much salt rises from under the ground to the
surface and ruins the soil. In 2000, there were 2.5
million hectares of salt-affected land in Australia.
This may increase to 17 million hectares by 2050.
Rising watertable
Land clearing is the major cause of Australia’s
dryland salinity problem. Trees act as pumps,
removing water from the soil and keeping
the water level in the ground well below the
surface. This level is called the watertable. Water
absorbed by the roots travels through the trunk
and out through the leaves into the air. In a day,
over 700 litres of water may pass through the
leaves of a fully grown river red gum.
Beneath the ground across much of Australia
there are large deposits of salt laid down by
ancient seas. The salt is harmless underground,
but when it comes to the surface it does
damage. When trees are removed the watertable
rises, bringing the salt with it.
Costs
The cost of salinity to Australia’s farming
production is over $250 million a year, and the
cost is increasing. The CSIRO estimates that
salinity will cause the extinction of 1000 species
of Australian plants and animals. Salinity also
damages water pipes, roads, houses and parks.
In the city of Wagga Wagga, this type of damage
costs over $3 million each year. The level of
salt in the Murray River is also increasing, and
by 2020 the water in Adelaide piped from the
Murray may be too salty to drink.
Halting the salt
Replanting native trees is a very effective method
of lowering the watertable. Native grasses have
long roots that prevent water from rising to the
surface, unlike many introduced grasses that
have shallow roots.

Slow change
For many years, the practices that led to today’s
salinity problems went on without anyone
knowing the consequences. This was because
the effects of land clearing on watertables were
not immediately obvious. Similarly, the effects
of changing these practices will not become
noticeable for decades, because it will take that
long for seedlings planted now to become trees
and restore watertables to their natural levels

The text suggests that Australia’s salinity problem
is a process that cannot be reversed.
would have occurred regardless of human infl uence.
was deliberately caused by farmers and land developers.
may have been averted had the right knowledge been available.

In a day, over 700 litres of water may pass through the leaves of a fully grown river
red gum. (paragraph 2)
This information in the text shows that trees
are the only things preventing underground salt rising to the surface.
play a vital role in preventing the watertable from rising.
are able to access and utilise water in order to grow.
contribute to the salinity problem.

In the section called Costs, it is implied that salinity affects
mainly the city of Wagga Wagga and the Murray River.
an unimportant part of society and the environment.
numerous aspects of society and the environment.
mainly farmers and their equipment.

In the section called Costs, the city of Wagga Wagga is mentioned to
describe how rural towns are responding to the salinity crisis.
give a real-world example of the high costs associated with salinity.
show that the costs of salinity are trivial when distributed across the
country.
show that the costs of salinity are restricted to rural areas and country
towns.

The section called Slow change suggests that Australian society
is as ignorant about salinity as it has always been.
may be about to cause another environmental emergency.
needs to act now if salinity is to be prevented in the future.
will be unable to predict the consequences of preventing salinity

The intended audience of this text is people who
are experts in salinity.
do not know much about salinity.
are replanting salt-damaged land.
are measuring the fi nancial costs of salinity