Brisbane flooding in 2010 to 2011 evidently had a major impact on the community, people and environment. The main causes that contributed to the flood were the overflow of the Wivenhoe dam, massive rainfall in Lockyer Valley and the ground not being able to soak the excess water that was pouring onto it. As a result these factors all contributed to the devastation of the Brisbane floods and the damage that it created for the people, environment and the society.
Wivenhoe Dam was seen as the biggest cause of the flooding in Brisbane.Wivenhoe dam had a huge impact on the devastation of the 2010-2011 floods in Brisbane and caused the most damage out of any other cause. Dams have fuse plugs, which are intended to fail; they erode as water flows over them, to prevent overtopping of the main Wivenhoe Dam wall. They fail and stop the flow of electrical current. Electrical fuses are expendable and save a much more expensive piece of equipment. Wivenhoe’s fuses are slightly different because instead of stopping the flow they divert some of it. If the flow exceeds the capacity of the fuse plugs, water will still flow over the wall destroying it. If this were safe, we wouldn’t need fuse plugs in the first place. If the fuse plugs and the gates cannot handle the volume of water coming into the dam, then water will flow over the main Wivenhoe wall. In that event, the main wall would fail, because, like the fuse plugs, the main wall is built from an earthen wall which is rock lined. The main wall of
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Wivenhoe is no more capable of surviving being over-topped than the fuse plugs are. The fuse plugs and the main wall are both built from earth, which will erode. The main wall of Wivenhoe has been designed so that it will fail if floodwater flows over it. Somerset Dam, upstream of Wivenhoe, is made of concrete, and is designed to be safely over-topped. In stark contrast with Wivenhoe, which is designed so that it will collapse if it is over-topped. That's why it is correct to state: Wivenhoe is designed to fail.
Therefore we can see that Wivenhoe dam was designed badly and because of this silly error, a terrible incident happened which ruined lives. The Wivenhoe dam was a key contributor to the flooding downstream over the period 11th–12th January 2011. This does not imply fault, but merely acknowledges that the water that caused much of the damage came from dam releases.
Therefore we can see that Wivenhoe dam was designed badly and because of this silly error, a terrible incident happened which ruined lives. The Wivenhoe dam was a key contributor to the flooding downstream over the period 11th–12th January 2011. This does not imply fault, but merely acknowledges that the water that caused much of the damage came from dam releases.
Massive rainfall in Lockyer Valley was a large cause in the Brisbane flooding, 2010-2011Lockyer Valley was affected by the rainfall and flooding and was a cause of even more serious damage in Brisbane area. The Weather radar shows that intense rainfall started in the northern parts of Fifteen Creek Mile, Murphy’s Creek and Alice Creek at approximately 12pm. It was in steep terrain and was already saturated from earlier rain, runoff and overland flows in those watercourses may have commenced within minutes. By approximately 1pm, all catchments in the Upper Lockyer Valley would have been experiencing heavy rainfall. There were gauges operating at Spring Bluff and Helidon but none in between. This lack of gauge information makes it difficult to establish at exactly what time the flash floods struck each township. A witness who lived at upper Lockyer near the town said that at about 1:47pm he saw a wave of water in the creek breaking in the distance, the force of the approaching water was ripping out trees in its path. The level of the creek rose about 12 metres in 12 minutes. By 2:51pm the water level had receded significantly.
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Surface area of the ground, not being able to soak in the excess water that was pouring onto the already soaked groundBrisbane's flooding was mostly caused by the dam but then this dam failure lead to many other smaller causes such as this cause, the lack of surface area and lack of time that the water had on the ground before more came. As extreme amounts of rain poured down onto the grounds of Brisbane, they became more and more saturated with water and could not hold it any longer. This was evident in Lockyer Valley where the uncontrollable and uncontainable amount of water flooding the area was not able to be removed in any way. The flooding was extremely fast and therefore there weren't many ways of stopping it and preventing it from getting worse, support was provided but many lives were changed for the worse after these tragic floods.
We can see that smaller causes of the flooding all come together with the larger causes of the Brisbane flooding to make a tragic event which was one that will never be forgotten |
BackflowThe suburbs and surrounding areas of Brisbane have been built on a low lying flood plain vulnerable to water inundation. Storms, heavy seasonal rain and flooding are a natural part of living in Brisbane and Brisbane City Council is committed to reducing the risk of flooding in our city. During the January 2011 flood, some parts of Brisbane were affected by water which came up from the river through the drainage networks and into the streets. This is referred to as backflow flooding. This increased the amount of water flowing into the streets and block the only way the on flowing water could escape therefore creating another contribute to this horrendous flood.
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