Description of floods
A flood is when water rises outside of its normal levels, and most of the time covers land
that is usually dry. In simple words it is when water inundates land that is usually dry.
Causes
The rise in water level, causing flooding can be due to many causes although the most
common in Australia is heavy rainfall. Australia is the driest inhabited continent on Earth, so
when there is a large downpour of rain it can often be more than the river systems can cope
with. Flooding can also be a result of another phenomenon, called coastal flooding when a
large storm of tsunami causes
the sea to surge inland. This can
cause the flooding of the
downstream area, even in dry
weather. The Queensland
floods were a result of heavy
rainfall caused by Tropical
Cyclone Tasha that combined
with The La Niña weather
pattern of 2010 which brought
the strongest wet conditions to
Eastern Australia since 1973.
This diagram shows one of the processes of flooding and is
specific to the causes of flooding in Australia.
.
These two diagrams show what floods are and some of the contributing factors leading to the flooding of an area
Case study: Queensland floods
2010-2011
Where the flooding happened
The Queensland floods were so widespread and devastating
that 70 towns were affected and three quarters of the state
declared a disaster zone.
On January 2011 Toowoomba, a city that sits on the top of the
Great Dividing Range, received 150mm of rain within a 40
minute period. The ground could not hold this much water and
the waters rushed from the top of the range down to the city. It
then spread down the mountainside and rushed through the
Lockyer Valley to the main dam that protects Brisbane from
flooding. The gates had to be opened, sending the equivalent of
two Sydney Harbour's worth of water into the Brisbane River
each day, which is why Brisbane and Ipswich flooded.
This diagram shows the total rainfall over
Queensland in December 2010, the time of
the floods.
The major places that were affected by these floods were the
Fitzroy river basin, the Burnett river basin, the Condamine/Balonne
river basin, Toowoomba, Lockyer Valley and the Brisbane river
catchment.
The floods hit the hardest in South East Queensland, and one of the
most affected areas was Toowoomba, which coordinates are
27.5500S, 151.9500E. Toowoomba is a city in Southern
Queensland and is located 127 km west of the capital city of
Queensland, Brisbane.
NASA satellite
image showing
swollen rivers
and cloud
cover.
This diagram shows the worse flood
affected areas in Eastern Australia,
and mainly Queensland.
The landform and climate
Queensland is described as having a subtropical climate because throughout the year the
temperature stays generally moderate.
However the floods occurred due to extreme weather patterns and the land not being able
to adapt to this. Since Australia had been in severe drought for many years previous to the
flooding, the rapid change from El Niño (warm and dry weather) to La Niña (cool and wet
weather) meant that the land was not used to the heavy rainfall and therefore was not able
to absorb it as well and prevent the land from flooding. The 2010 La Ni ña weather pattern,
which brings wetter conditions to Eastern Australia, caused the event of heavy rainfall over
Queensland river catchments.
Another influence of the landform and climate in Queensland is the Great Dividing Range, it
runs along the east coast of Australia, from Queensland down to Victoria, it acts as a barrier
and influences the climate on the east coast of Australia. This is why there is more
vegetation and rainfall on the East Coast of Australia. Another connection to the floods and
the landform of Queensland is that more precipitation is formed on the side of the
mountain facing the prevailing winds because the air will rise when it comes in contact with
the range, this could be another reason as to why some areas were more affected than
others.
Here is a photograph of the
sea surface temperature in
January 2011, which shows
the weather patterns to do
with La Niña and how this
affected Australia and its
climate.
Towoomba
D
J
Airport
Temperature
(C)
23.6
Rainfall
(mm)
399.2
F
M
A
M
J
J
A
S
O
N
26
27.4
24.8
22
18.2
15.6
15.8
18.2
21
21.8
27.3
413
108.4
120.4
42.8
69.6
11
13.4
66.6
22.4
89
74.4
Changes due to the flooding
Social changes
Some immediate social impacts of floods are the loss of human life, separation of families,
damage to property, destruction of crops, loss of livestock and the deterioration of health
conditions for example waterborne diseases. The Queensland floods devastatingly took 35
lives and affected more than 200,000 people.
There is also an emotional and mental effect on the victims, many are traumatised by the
loss of loved ones, the loss of property and the disruption to business and work due to the
breakdown of communication links like roads and bridges can cause much stress. Some
flood victims also live in fear of the disaster happening again.
Economic changes
One of the most affected industries of the Queensland floods was the coal industry. In
January 2011 they expected that the floods would strip $2.5 billion from the earnings of the
Australian mining sector. Queensland supplies 60% of the world’s coal exports and when the
disaster of the flood hit and these businesses crashed the cost of coal was enormous. The
direct and primary damages to mining operations were caused by the flooding of the mines
but companies also encountered problems with coal transports due to the breakdown in
roads and infrastructure.
Farming and agriculture was also hit hard, with an estimated $1.6 billion worth of crops
having been destroyed. Queensland is the leading producer of fresh produce in the country
meaning that essential things such as fruit, vegetables, cotton, sugar, grains and beef were
limited in not only Queensland but the whole of Australia. There was also a significant
damage to infrastructure across Queensland, and an estimated 18,000 residential and
commercial properties damaged in Brisbane and Ipswich.
Environmental changes and impacts
When a flood occurs there is an excessive amount of sediments and nutrients entering the
waterway, which has many negative impacts to the plants and wildlife surrounding it.
One major environmental impact of the flooding was the health of the waterways as many
rivers and creeks were eroded, contaminated and littered with debris. Also the dirty water
that covered most of Queensland was full of dangerous toxins and chemicals which entered
the water making it poisonous and unsafe for the animals and destroying their natural
habitats.
The floods were so fast and destructive that nearly everything on the ground had been
washed away, having a massive impact on the surrounding flora and fauna.
Response to the floods
On an individual level, people helped to aid the victims of the floods by offering personal
support and volunteering. More than 55,000 volunteers registered to help clean up the
streets of Brisbane with also thousands of unregistered volunteers helping as well. The state
and federal governments also helped by establishing a national appeal and giving
approximately $1 million each. The Prime Minister also toured the flood affected areas and
helped to make Australia aware of the devastation.
Sport teams also helped to aid the damages, for example before the 2011 Australian open
many players took part in the ‘Rally for Relief’ which raised approximately $750,000 and the
2011 Legends of Origin Charity match was held which raised $380,587 to go towards the
recovery effort. Also major charity organisations such as The Australian Red Cross and the
Salvation Army helped to provide aid and recovery to the victims of the floods.
Simple prevention strategies that have been urged to be put into place across Queensland
homes are: ensuring your electrical panel is in a high position above the flood level, install
check valves in sewer traps to prevent floodwater from backing up into the drains of your
house, adding a waterproof veneer to exterior walls and keeping a supply of sandbags to
place up against doors to prevent water from entering your house
Bibliography
 http://www.chiefscientist.qld.gov.au/publications/understandingfloods/consequences.aspx - The State of Queensland (Department of
the Premier and Cabinet) Queensland Government – Last update 14
September, 2012
 http://www.ibisworld.com.au/common/pdf/QLD%20floods%20special%
20report.pdf – IBISworld – January 2011
 http://www.wildlife.org.au/news/2011/flooding5.html – Wildlife
Queensland – Last updated 16 February 2012
 http://www.indymedia.org.au/2011/01/06/the-queensland-big-wet-bigflood-and-climate-change – Australian Coal Association – Last updated
6th January 2011
 http://www.redcross.org.au/queensland-floods-2011.aspx – Bradley
Kanaria, Australian Red Cross - 2013
 http://www.bom.gov.au/climate/data/index.shtml – Australian
Government, Bureau of Meteorology- Page updated 16th August 2012
 http://www.brisbanetimes.com.au/environment/weather/qldfloods –
Katherine Feeney, Brisbane times - Article written on 17th January 2011
 http://www.crikey.com.au/topic/queensland-floods-2011/ - Freelance
journalist, Amanda Gearing - August 2nd 2011
Word Count = 1,056 words (not including the bibliography)