The NHPC Limited recently achieved a key construction milestone with the
daylighting of Diversion Tunnel-3 of the Dibang Multipurpose Project in Arunachal Pradesh.
Daylighting means the tunnel excavation is complete from both ends and opened to the surface,
indicating readiness for river diversion.

About the Project

• A 2,880 MW flood control-cum-hydroelectric project on the Dibang River, a tributary of the Brahmaputra, in Arunachal Pradesh.
• Will become India’s tallest concrete gravity dam (around 278 metres) after completion.
• Developed by the state-run National Hydroelectric Power Corporation (NHPC).
• Located near Munli village in the Lower Dibang Valley district of Arunachal Pradesh.
• Designed as:
  • An energy storage project to stabilise renewable energy supply.
  • A flood moderation project reducing downstream flood risks in Assam.
  • A contributor to India’s clean energy transition under national climate commitments.

Key Features

• Dam Structure: 278-metre high and 375-metre long concrete gravity dam, which resists water pressure mainly through its own weight.
• Construction Technique: Built using the Roller Compacted Concrete (RCC) method, enabling faster construction and high structural strength.
  It will be the highest RCC dam in the world.
• Reservoir: About 43 km long with 3.85 billion cubic metres of gross storage capacity.
• Hydropower System: Six head-race tunnels and six tail-race tunnels connected to an underground powerhouse.

Key Objectives

• Generation of clean and renewable hydroelectric energy.
• Flood moderation in downstream Assam.
• Strengthening energy security of the Northeast.
• Supporting India’s climate commitments under the Paris Agreement.

The project aligns with India’s renewable expansion strategy under the
National Electricity Policy and the National Action Plan on Climate Change,
particularly the mission on sustainable energy.

Prelims Practice Question

With reference to the Dibang Multipurpose Project, consider the following statements:

1. It is located in Arunachal Pradesh on a tributary of the Brahmaputra.
2. It will be India’s tallest concrete gravity dam.
3. Its primary objective is thermal power generation.

Which of the statements given above is/are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 only
(d) 1, 2 and 3

Answer: (a) 1 and 2 only

One-line wrap: The Dibang Multipurpose Project reflects India’s push to harness the Northeast’s hydropower potential
while balancing energy security, flood control, and environmental responsibility.