Question

Write an essay need of dam.

Answer 1

A dam is built to control water through placement of a blockage of earth, rock and/or concrete across a stream or river. Dams are usually constructed to store water in a reservoir, which is then used for a variety of applications such as irrigation and municipal water supplies. Reservoir water can also be directed to flow through hydraulic turbines, producing electric power for use in homes and industries. Hydroelectric power is considered a renewable source of energy because the reservoir water that is used to generate electricity is continuously replenished. A dam using locks and canals, such as the series of locks on the Panama Canal, enables navigation through a human-made water route that must overcome elevation differences.

The disadvantages of dams include the resulting flooding of large areas of land (destroying flora and fauna), altering the physical characteristics of the river below the dam (also affecting flora and fauna), impeding 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.

Answer 2

Most dams are designed to accomplish a variety of functions, which include flood control, flat water recreation, hydropower electricity generation, and water supply. Although these seem like good reasons for the existence of dams, this type of constructions bring greater negative effects than good ones. The "environment effects of dams include loss of land and biological resources to inundation, reservoir sedimentation and downstream erosion, and hydrological changes unfavorable to many native or desirable species." Dams just strangle rivers and the perfect example of the damage dams cause to rivers is what is happening to the Mekong River in Asia.

The Mekong river covers more than 4500 kilometers through 6 countries.

These types of damages are being revaluated to see if the benefits of these dams are superior to the environmental and social costs. The Comision of The Mekon river, an organization which normally defends development in Laos, Thailand, Cambodia, and Vietnam, said that "the ecosystem of the Mekong was deteriorating" and added: "If the current riddem of damage continues, the forests, the biodiversity, the existence of fish and quality of the soil will all be damaged to the point were recuperation will be impossible. 

For some years now, many Asian countries have looked at the Mekong River as an opportunity to generate electricity and with this be able to develop faster. Being that most of the regions around the rive are poor governments have looked at the Mekong as a way to produce money. China and Laos in particular have argumented about the potential the river can give them