Dam / Importance Of Dam

 

Essay On Dam / Importance Of Dam

Global warming and shortage of water are two main threats for whole world in next coming decades. To face this threats dam is one of the useful source.
A dam is a barrier that stops or restricts the flow of water or underground streams. A reservoir is a human-made lake created by building a dam.  Dams and reservoirs not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigation. Hydro-power is often used in conjunction with dams to generate electricity. During times of excess water flow, dams store water in the reservoir; then they release water during times of low flow, when natural flows are inadequate to meet water demand. Dams retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions. When engineers design and maintain dams, they consider all these purposes.

Dams can be formed by human agency, natural causes, or even by the intervention of wildlife such as beavers. Man-made dams are typically classified according to their size , intended purpose or
structure. Based on structure and material used, dams are classified as easily created without materials, arch-gravity dams, embankment dams or masonry dams, with several sub-types.

Dams are also found to have a role in the increase or decrease of global warming. The changing water levels in reservoirs are a source for greenhouse gases like methane. While dams and the water behind them cover only a small portion of earth's surface, they harbor biological activity that can produce large amounts of greenhouse gases.

Dams have served people for at least 5,000 years, as evidenced in the cradles of civilization, in
Babylonia, Egypt, India, Persia, and the Far East. The remote history of dams is not well known. So we can not ignore the importance of dam.

But there are some disadvantages of dams include the resulting flooding of large areas of land and altering the physical characteristics of the river below the dam effecting plants and animals, prevent fish migration, and killing large numbers of fish that pass through hydroelectric turbines. In recent years, engineers and scientists have begun to manage reservoirs and their releases to be less harmful to aquatic and terrestrial wildlife and plants, as well as humans residing below the dam a method of
water resource management called adaptive management.

In Pakistan, water stress is a major issue. Although Tarbela Dam is one of the largest earth-filled dam in the world lies  on the Indus River in Pakistan, but It can not cover the need of whole land that is why Pakistan  have been made efforts to build more dams. In recent months, WAPDA has been attempting to build the Diamer-Bhasha Dam. The dam lies between the two provinces Khyber-Pakhtunkhwa  and Gilgit-Baltistan. And it will help Pakistan in future to face major problems like shortage of water, insufficient electricity and global warming.