Earth Scienace: Dams and Reservoirs, Essay Example

Drawbacks of Building Flood-Control Dams

Construction of flood-control dams results in destruction of the land area and the environment. Selection of site for building a dam is difficult and will affect the people and the environment (Lutgens, Tarbuck & Tasa, 2010). The building activities can harm the environment by causing noise and air pollution. It is more expensive to build these dams and consumes more time. Also, the river system gets disrupted because of these activities. Silt from the water flowing through the rivers gets accumulated in the dams if proper care is not taken and the capacities of the dams get reduced in a very short period of time. Sometimes loss of sedimentation below the stream occurs, and this is referred to as delta starvation. Constructing a dam floods a large area upstream and affects the ecology of that area (Lutgens et al., 2010). For example, the creatures which move upstream, like fish are mostly affected.

Reservoir Behind a Dam

A reservoir is an artificial lake which is created by building a dam across a river. The main objective of building the reservoirs behind the dams is to store large volumes of water. Because of this, the stress on the earth’s crust is increasing day-by-day and as a result earthquakes are caused. Also, these reservoirs are used for controlling the floods and reduce the damage caused on the downstream. The reservoir behind a dam captures most of the silt which leads to the sedimentation in the reservoir (Lutgens et al., 2010). Accumulation of these sediments in the reservoir reduces the ability of the dam to store water. Thus the storage capacity and effectiveness of the reservoir behind the dam decreases. The accumulation rate of the sediments depends on the reservoir size and the amount of silt in the water flowing through it. A small reservoir behind the dam will lose its capacity very quickly, where as it takes very long period of time for wide-area reservoirs behind the dam to lose its storage capacity.

Reference

Frederick K. Lutgens, Edward J. Tarbuck, and Dennis Tasa. (2010). Foundations of Earth Science. (6th ed.). Boston, MA: Prentice Hall.