The longest man-made dam of India is also the longest earthen dam in the world. HIRAKUND dam is the longest dam in India which is situated on the Mahanadi River in the Orissa state of India. The length of the Hirakund dam is recorded 25.8 km or 16 miles. However, the length of the main section of the dam is only 4.8 kilometres long. With this incredible 25.8 km length, Hirakund dam is not only India’s longest man-made dam, but it is also the world’s longest man-made earthen dam. It is a composite structure of earth, concrete and masonry and the lake formed due to the construction of the Hirakund dam is the largest artificial lake in Asia. The reservoir holding capacity of this lake is 743 square kilometres. The Hirakund dam has a height of 60.96 meters.
It was Shri M. Visvesvaraya who for the first time (1936) proposed a plan to construct this dam to control the water flow in the Mahanadi river basin. It was intended to control the frequent devastating floods of this region. The construction to build Hirakund dam was started in the year 1948 and was formally inaugurated by the first prime minister of India Shri Jawaharlal Nehru on 13 January 1957. The Hirakund dam project is also India’s first river valley project.
Hirakund dam: the longest man-made dam of India and the world
The main length (4.8 km) of the Hirakund dam spans between two hills; on the left side Lamdungri and at the right Chandili Dunguri hill. This length of the dam is extended by earthen dykes on both left and right sides, which add another 21 km to the total length of the dam. There are two observation towers on each side of the hills. These towers are named as the “Gandhi Minar” and the “Nehru Minar”. The construction of the Hirakund dam has greatly controlled the devastating floods and droughts in the Mahanadi delta region. Now the Hirakund reservoir irrigates 7,500,000 hectares (75000 square kilometres) of land. Due to the availability of irrigation water, these areas have become good agricultural producers. The Hirakund dam has a total installed capacity of 347.5 MW. This incredible dam has 98 flood gates, 64 sliding gates and 34 crest gates to release flood water, making it one of the best-designed dams in the world.
The construction of Hirakund dam has made it possible to grow and support Kharif and Rabi crops in Mahanadi River delta areas, particularly in the Bargarh, Bolangir, Sambalpur and Subarnapur regions. The reservoir also attracts migratory birds.
- Hirakund Dam: Some Facts
- Height 60.96 meters
- Length: 25.8 km
- Type: Composite Dam
- Reservoir Capacity: 5,896,000,000 cubic meters (4,779,965 Acre feet)
- River: Mahanadi River
- Location: 15 km north of Sambalpur, Odisha
- Installed capacity: 347.5 MW