Dams or reservoirs are those structures across a River or stream that hold water and are used for the purpose of generating electricity. This kind of electricity is known as hydroelectricity.
Based on its structure Dams are of 8 types. In this article you will get to know about some famous Dams in India along with the name of Rivers they are built upon and some questions that are generally asked in exams like Bank, SSC, Railways etc.
Types of Dams
In the ancient times Dams used to be built of natural materials like rocks or clay but in modern times they are made up of concrete material. So based on the structure Dams are of following types:
- Gravity Dams : It is constructed from concrete or stone masonry and 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. Its ex: Anagpur Dam built in the era of King Anangpal 1 of Tomar dynasty, in Faridabad, Haryana.
- 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. Ex: The arch dam in Idukki, built across the Kuravan and Kurathi hills, is the world’s second and Asia’s first arch dam.
- Barrage Dams : 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 stabilise river water elevation upstream for use in irrigation and other systems. Ex: Farakka Barrage across the Ganga river located in Murshidabad, West Bengal,18 km (11 mi) is the largest barrage of India.
- Arch-Gravity Dam: With the Characteristics of both arch and gravity it is a dam that curves upstream in a narrowing curve that directs most of the water pressure against the canyon rock walls. Ex: Changuinola Dam is an example of the RCC arch-gravity dam.
- 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.
- Earth-fill dams: Earth-fill dams, or earthen 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. Ex: Banasura Sagar Dam, Wayanad, is the Largest earth dam in India and the second largest in Asia.
- Rock-Fills Dams: Rock-fill dams are embankments of compacted free-draining granular earth with an impervious zone. The earth utilised often contains a high percentage of large particles, hence the term “rock-fill”. Ex: Tehri Dam 260.5 m on Bhagirathi river is the highest rock filled dam in India which is also listed in top 10 highest Dams in the World.
- 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.
Highest, Largest, Longest, Oldest Dams In India
- Tehri Dam located in Uttarakhand on Bhagirathi river is the highest rock fill dam and one of the top 10 dams in the world.
- Bhakra Nangal Dam 225m on Sutlej in Himachal Pradesh & Punjab is the Largest dam in India with world ranking 2.
- The Hirakud Dam on Mahanadi in Orissa is the longest dam in India with a total length of 25.79 km.
- The Nagarjuna Sagar Dam located in Telangana is India’s largest Masonry Dams built till date. It is the largest manmade lake in the world. It has 26 gates and is 1.55 km in length. It is situated on the river Krishna.
- The Sardar Sarovar Dam located in Gujarat on Narmada river is the largest dam in the Narmada Valley Project. It is a gravity dam with a capacity of 1450 MW.
|Category Of Dam||Name Of Dam||Speciality Of Dam|
|The Highest Dam||Tehri Dam(Uttarakhand)||Height Of Dam : 260.5 meters
Length of Dam : 575 meters
Dam on River : Bhagirathi River
Location of Dam: Uttarakhand
Dam completed in : 2006 (1st phase)
|The Longest Dam||Hirakud Dam (Odisha)||Total Length of Dam: 25.79 km (16.03 mi)
Length of Main Dam: 4.8 km (3.0 mi)
Dam on River : Mahanadi
Location of Dam : Odisha
Dam Completed in :1953
|The Oldest Dam||Kallanai Dam(Tamil Nadu)||Location of Dam : Tamil Nadu
Dam on River : Kaveri , Year of Completion : 100 BC-100 AD
The Report Of Chopra Committee
The committee headed by Dr Ravi Chopra was appointed by the Ministry of Environment and Forests in 2013, following the Supreme Court’s suo motto order of August 13 2013. It was formed to study whether the HEPs exacerbated the deluge that caused massive destruction in Uttarakhand in June 2013.
Dr Ravi Chopra in his report said: “Seventy-six HEPs of more than 3,100 MW capacity in the State of Uttarakhand are in the periglacial region. In our report we have proposed that no HEPs should be built in the paraglacial region as it has loose glacial debris which when carried downstream can be disastrous.” The report also objected to the construction of Hydroelectric power in regions between 2,200 to 2,500 metres above sea level.
List Of Dams In India
|List Of Major Dams in India||State||River|
|Bhavani Sagar dam||Tamil Nadu||Bhavani|
|Rihand Dam||Uttar Pradesh||Rihand|
|Mettur Dam||Tamil Nadu||Kaveri|
|Indira Sagar Dam||Madhya Pradesh||Narmada|
|Sardar Sarovar Dam||Gujarat||Narmada|
|Nagarjuna Sagar Dam||Telangana||Krishna|
|Bhakra Nangal Dam||Punjab-Himachal Pradesh Border||Sutlej|