Dams in India

 What is the Dam?

A dam is a barrier that stops the flow of water and results in the creation of a reservoir. Dams are mainly built in order to produce electricity by using water. This form of electricity is known as hydroelectricity.

Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability.

The earliest known dam is the Jawa Dam in Jordan, dating to 3,000 BCTypes of Dams

There are many dams in India, and hence there is a need to know about them as there are questions based on the dams of India. The Bank Exams like IBPS or SBI contains questions from this section.

Based on the structure the types of dams are as mentioned below:

1. Arch Dam: An arch dam is a concrete dam that is curved upstream in the plan. It is designed so that the hydrostatic pressure (force of the water against it) presses against the arch, causing the arch to straighten slightly and strengthening the structure as it pushes into its foundation or abutments. An arch dam is most suitable for narrow canyons or gorges with steep walls of stable rock to support the structure and stresses.
2. Gravity Dam: Dams constructed from concrete or stone masonry are Gravity dams. They are designed to hold back water by using only the weight of the material and its resistance against the foundation to oppose the horizontal pressure of water pushing against it. These are designed in such a way that each section of the dam is stable and independent of other section.
3. Arch-Gravity Dam: This dam has the characteristics of both an arch dam and a gravity dam. It is a dam that curves upstream in a narrowing curve that directs most of the water pressure against the canyon rock walls. The inward compression of the dam by the water reduces the lateral (horizontal) force acting on the dam.
4. Barrages: A barrage is a type of low-head, diversion dam which consists of a number of large gates that can be opened or closed to control the amount of water passing through. This allows the structure to regulate and stabilize river water elevation upstream for use in irrigation and other systems.
5. Embankment Dams: An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil, sand, clay, or rock. It has a semi-pervious waterproof natural covering for its surface and a dense, impervious core.
6. Rock-Fills Dams: Rock-fill dams are embankments of compacted free-draining granular earth with an impervious zone. The earth utilized often contains a high percentage of large particles, hence the term “rock-fill”.
7. Concrete-face rock-fill dams: A concrete-face rock-fill dam (CFRD) is a rock-fill dam with concrete slabs on its upstream face. This design provides the concrete slab as an impervious wall to prevent leakage and also a structure without concern for uplift pressure.
8. Earth-fill dams: Earth-fill dams, also called earthen dams, rolled-earth dams or simply earth dams, are constructed as a simple embankment of well-compacted earth. A homogeneous rolled-earth dam is entirely constructed of one type of material but may contain a drain layer to collect seep water.