Man made walls on rivers

Posted by Freddy on Jul-10-2010

A dam is a barrier that impounds water or streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Dams were first constructed in Mesopotamia and the Middle East, where dams were used to control the water level. The earliest known dam is sited in Jawa, which is situated in Jordan. Dams can be formed by natural causes and by the intervention of wildlife such as beavers. Dams are even formed by human agency.

Man-made dams are typically classified according to their size, structure and the purpose of dam. Based on size, dams are classified as large and major dams. International standards define large dams as higher than 15-20 meters and major dams over 150-250 meters in height. Based on structure and material used, dams are classified as timber dams, arch-gravity dams, embankment dams or masonry dams, with several subtypes.

Dams and hydroelectric projects are constructed to fulfill needs of human beings. These hydroelectric projects are generally considered as environmental friendly because it represents a clean and renewal source of energy. These projects are made with huge promises throwing light on the reward alone. But many a times the impacts of these dams turn out to be ridiculous.

The ecological system is the first that gets disrupted by the construction of these dams. Apart from all these factors these have many environmental issues related to them. These hydroelectric power plants result in submersion of extensive areas upstream of the dams, destroying biologically rich and productive lowland and riverine valley forests, marshland and grasslands. Many a times issues are roused due to the lack of study done before implementing the project.

Dam failures are generally catastrophic if the structure is breached or significantly damaged. The dam failures have been some of the largest manmade disasters in history. A good design and construction are not adequate guarantee of safety, sometimes some geological eruptions can pull down them down. Dams are used primarily for storage of water and retaining the same. There are flood gates used to release water as in when required and more over to control the water pressure present in the dam. The water that flows out of the dam is also used for producing electricity using hydroelectric power. What happens when a dam is ill built or not maintained properly, cracks will appear and the same can be very fatal as the dam can burst thus leading to destruction to life and property worth millions. We need to ensure that our dams are well kept and regular maintenance is done to avoid such catastrophes.

  1. Ricky Said,

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