DAMS: GOOD OR BAD
The unequal availability of resources leads to the development of methods to store them. Water as the prime resource for survival has been the determining factor for human settlements, been the sole reason for communities to thrive and for long formed the basis for wars.
In locations where the appearance of rainfall is scanty and unreliable, the need to store water has given rise to the creation of ‘tankas’, creation of man-made lakes and similar reservoirs. However, these methods allow for temporary availability and demand replenishment.
Dams form a viable option in places where factors like foundation conditions, low possibility of seismic activity have been ascertained. It is necessary to study the chemical characteristics of ground water and the possible effects of temperature and pressure changes on the environment. When the necessary surrounding parameters are satisfied, dams are deemed to bring positive effect.
Like any measure to divert and stem the flow of water will, dams represent the possibility of a number of disadvantages.
Prior to the arrival of technology to allow for huge structures to direct the flow of water, simple techniques were popular in villages. These rough structures were useful for small groups and communities. However, with the increase in the size of human settlements the demand for water supply increased. The direction of water towards thriving human settlements allows for economic growth. The search for methods to harness water resources develops from the desire for a prosperous thriving community.
Industry, transport, entertainment, agriculture and domestic needs are met effectively with the development of dams. It is clear that the benefits of this method are the reason why many communities the world over have chosen it.
Yet, there is a huge debate about the dams and the disadvantages they bring up. The effect on the environment and communities is quoted as the cause for debate.
The objective of the study is two-fold:
* to understand the pros and cons of damming as a means to regulate water flow * understand the different types of dams and their suitability to the conditions of a region
Actual presentation of the project
Types of dams and their relevance
Dams may divert the flow of river water into a pipeline,/ canal or channel. Some raise the level of inland waterways to make them navigable by ships and barges. Many dams harness the energy of falling water to generate electric power. Dams also hold water for drinking and crop irrigation, and provide flood control. Dam building can be very beneficial in restoring wetlands. Such wetland benefits include flood control downstream, biodiversity (by providing habitat for many rare as well as common species), and water cleansing, both by the breakdown of toxins such as pesticides and the retention of silt.
Once a decision for water diversion is taken, the question arises about the most suitable design and structure. The environmental factors that must mould the choice are:
Thermal stress – a study of the ambient temperature over a long period, in a variety of situations, over different dam sections is necessary to avoid cracking and potential for disasters. The structure must be designed to withstand varying temperatures of flowing water and varying weather conditions. Usage of dam capacity – The dam capacity is expected to cater to specific needs of the surrounding area. Underutilization can lead to flooding while overutilization leads to stress on the water table. Gains and losses – dams may be built across river valleys to form a reservoir. The reservoir or catchment area is created by removing existing settlements. People lose land and livelihood in this area due to inundation. Besides, water logging and increased salinity of adjacent land reduces arability. The downstream areas gain from the ready availability of water for the purpose of...
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