This chapter explains the concept of dams. It mainly focuses on the dams in India. The chapter discusses the purpose as well as history of dams. The author collected data from various sources in order to perform graphical analysis to support the study. A comprehensive review of various scientific and research papers is done by the author to find the gaps in the research in the recent years. Some new dam projects are also briefly mentioned in the chapter. Plus, the author worked in the direction to find whether the current number of dams in the world, including India, is enough or not. Then, would building more dams replace the use of non-renewable sources of energy completely by itself or not? These are the matters that are mentioned in the chapter.
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A dam is any structure which was built across a river, stream or estuary, for water retaining purpose. They are normally built to supply the retained water for different purposes, in order to be used by people for their day to day activities, for industrial activities, and to irrigate semi-arid and arid lands. To generate hydroelectric power, dams are required to increase water’s quantity. Similarly, dams help in increasing the depth of a river water in a given place in order to enhance navigation on waterbody, as well as permit ships along with barges to travel smoothly, and also in cases of heavy snowmelt or large storms, it should have the ability to decrease the peak discharge of flood water. They also are able to give a lake, which can be used for activities which are amusing ones, like fishing, swimming as well as boating. There are numerous dams which are constructed not for only one purpose but for two or more purposes, like for instance, the water present in one particular reservoir can be utilized for to assist in the irrigation system of a given area, also to generate hydroelectric power to be used in nearby areas and also for fishing by people. Such water controlling structures are frequently labelled as multipurpose dams. Supporting works which are able assist dams in order to allow them to function in a proper way, consists of movable gates, spillways as well as valves, which control the discharge of extra water downstream from the dams. The dams also consist of intake structures which can supply water to a power station or to tunnels, canals, or pipelines intended to transport water stored by the dam to faraway places. Further supplementary works are locks to allow the passage of ships to go through the dam site or around it, systems used to flush out or clear out the silt which mounts up in the reservoir, as well as fish ladders along with other devices to help fishes in looking for to swim past a dam or around it. Dams can also act as main structures in multipurpose schemes which are intended to save water resources in some particular regions. In developing countries, multipurpose dams have exceptional significance, as a single dam is able to bring numerous benefits like industrial growth, the development of agriculture in that region as well as hydropower generation to be used for other activities. Nevertheless there is an important concern related to the environment has arisen because of dams, as the dams affect the riparian ecosystems as well as migrating fishes in a negative way. Additionally, massive land areas which were people’s home initially and covered with vegetation can be submerged because of the creation of large reservoirs. This has raised people’s opposition to the dam projects in large groups in many areas, leading to protests in different forms, as many people questioned the concerned authorities about the benefits offered by such projects are adequate enough after such great losses. According to engineering terms, dams can be classified into different categories like based on building materials as well as based on structural types of dams. The type of dam which will be build is generally decided based on the construction materials available in the place or nearby, the valley’s foundation conditions, experiences of the concerned engineers, promoters as well as financers who are accountable for the given project, and site accessibility to the transport facilities or to the transport network. According to the dam engineering of the current times, rockfill, earthfill and concrete are the materials among which the concerned authorities of the project has to make a decision to build the dam in a given place. However in the past, jointed masonry was the material responsible for the making of various dams, later on it became outdated and it was replaced by concrete. Huge gravity dams, buttress dams as well as thin arch dams are being built using concrete from several decades in the modern era. With roller compacted concrete’s development, high quality concrete was indorsed in sufficient quantities in order to be placed with the equipment type which was initially made to combine, distribute as well as move earthfill. Typically rockfill as well as earthfill dams are normally assembled together in a group which is named as embankment dams, as they create enormous rock as well as earth dunes, which can be gathered into daunting embankments which are manmade structures.