Which Are 3 Biggest Dams in Bihar? Know All About River, District, Length and Year Built

The state of Bihar is influenced heavily by many river systems like the Ganga, Son, Gandak and Kosi. These river systems have led to the construction of many barrages for controlling the flow of water from these rivers into the canals. Some of the most prominent barrages include the Indrapuri Barrage on the river Son, Kosi Barrage on the river Kosi and Valmiki Nagar Barrage on the river Gandak.

Which Are the 3 Biggest Dams in Bihar?

Rank	Barrage	River	District	Length	Year Built
1	Indrapuri Barrage	Son	Rohtas	1,407 m	1968
2	Kosi Barrage	Kosi	Supaul	1,150 m	1962
3	Valmiki Nagar Barrage	Gandak	West Champaran	743 m	1969

The key thing to note for the aspirant is that all these three are barrages rather than traditional dams. A barrage uses gates to control the flow of water from the river into canals and is thus crucial in irrigation and flood control.

1. Indrapuri Barrage – Longest Major Barrage in Bihar

Indrapuri Barrage, also known as the Sone Barrage, has been built on the Son River in Rohtas district. The length of the barrage is roughly 1,407 metres and it is the longest among the three barrages.

The construction of this barrage dates back to 1968 and it is linked to the development of Son canal system. The old Dehri Anicut that had been built in 1873 has been replaced by the new one. The canal system of this barrage has been instrumental in providing irrigation water to agricultural lands of south-western Bihar.

Geography of Bihar – Indrapuri → Son River → Rohtas.

2. Kosi Barrage – Taming the “Sorrow of Bihar”

The Kosi Barrage, popularly known as the Bhimnagar Barrage, is located on the Kosi River near the India-Nepal border in the Supaul district. The barrage is around 1,150 metres in length and was built in 1962.

The Kosi River is popularly known as the “Sorrow of Bihar” due to its notorious flooding and tendency for course shifting. The barrage was constructed as an attempt to tame the river.

The Kosi Project is also important in terms of water cooperation between India and Nepal. An agreement related to the Kosi project was signed by both countries on 25 April 1954.

Exam fact: Kosi River → Sorrow of Bihar → Kosi Barrage/Bhimnagar Barrage → Supaul.

3. Valmiki Nagar Barrage (Gandak Barrage)

This barrage on the Gandak River is located in the West Champaran District of Bihar close to the India-Nepal border. The length of the Valmiki Nagar Barrage is 743 meters, and its construction date is 1969.

It helps to distribute the waters of Gandak through the Eastern Main Canal and the Western Main Canal for irrigation in the extensive agricultural lands. Moreover, this barrage is of geographical significance since it is located near the Valmiki Tiger Reserve, which is the only tiger reserve in Bihar state.

For exams, remember the following relation: Valmiki Nagar Barrage → Gandak River → West Champaran.

Why are These Barrages Significant to Bihar?

The economy of Bihar is predominantly based on agriculture, but the state also experiences floods repeatedly. In such a scenario, the functions of the large barrages are manyfold,

• Irrigation: River water is channeled through canals into farms.
• Flood control: Gates manage the flow of water from the rivers.
• Water allocation: Water is diverted through the barrage into canals.
• Economic development: Irrigation leads to increased agricultural production.
• Relevance to India-Nepal: Kosi and Gandak projects are connected to rivers flowing between these two countries.

They also reflect one geographical truth about Bihar: the rivers which bring rich soil also pose danger of floods.