DAMS AND RESERVOIRS
Dams are the storage works constructed for storing water and utilizing the same for irrigation and other purposes.
In other words, A dam is an obstruction or barrier built across a stream or river that impounds water or underground streams.
Dams are constructed for the purpose of storing water on the upstream side and forming a lake or pool of water generally called a reservoir.
Reservoirs created by dams suppress floods and also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigation.
The construction of dam is a major irrigation project because it requires greater understanding in planning and design.
TYPES OF DAMS
1) Earthen dams
2) Gravity dams
IMPORTANCE OF DAMS & RESERVOIRS
Dams are constructed to fulfill the following objectives or functions:
1) For supplying the storage water for irrigation, domestic use, and for industrial use.
2) For generating hydro- electric power.
3) For preventing the property and loss of lives on the downstream side from the effects of floods.
4) For diversion of water to other drainage or reservoir to increase flow there and improve water use in that particular area.
5) To control and stabilize water flow.
SELECTION OF SITE FOR DAM
Following points should be considered while selecting a site for dam construction :-
1) A dam should be located in a narrow part of a deep river valley.
2) The dam site should have a good foundation for its stability.
3) The dam site should have sufficient space for providing living accommodation for labors and engineer staffs.
4) The dam site should located above the agricultural area to be irrigated.
5) There should be easy availability of materials of construction.
6) The dam site should reasonably water-tight so that stored water does not escape through waterbeds and sidewalls.
7) The dam site should have sufficient space for spillways.
8) The general bed level should be preferably higher than that of river basin, thereby reducing the height of dam and facilitate the drainage problem.
TYPES OF EARTHEN DAMS
The types of earthen dam depend upon availability of foundation and materials used for its construction.
They may be of following types :-
1) Homogeneous type
2) Zoned type
3) Diaphragm type
