Kurichu Dam

The Kurichu Dam (also spelled Kuri Chhu Dam) is a major hydroelectric project situated in the Mongar District of eastern Bhutan, built across the Kurichu River, a tributary of the Manas River system that eventually joins the Brahmaputra River in India. The dam is a key element of Bhutan’s national hydropower development strategy, implemented with Indian collaboration, and serves as an essential source of clean energy, regional development, and Bhutan–India cooperation.

Geographical Setting and River System

The Kurichu River, locally called Kuri Chhu, rises in the northern Bhutan Himalayas and flows southward through narrow valleys and rugged gorges before entering India’s Assam State. The Kurichu Dam is located near Gyalpozhing, between Mongar and Lhuentse, approximately 520 kilometres east of Thimphu, Bhutan’s capital.
The catchment area of the river is mountainous, covered with mixed forest and subject to high monsoon rainfall. The Kurichu sub-basin is part of the Manas River basin, which itself forms a major component of the Brahmaputra River system.

Historical Background and Project Development

The Kurichu Hydropower Project was conceived as part of Bhutan’s effort to harness its enormous hydropower potential, estimated at over 30,000 MW, under the country’s policy of environmentally sustainable growth. The project was developed with technical and financial support from the Government of India, under the broader Bhutan–India Hydropower Cooperation Agreement.
Construction began in the mid-1990s, under the direction of the Kurichu Project Authority (KPA) and with engineering assistance from India’s Central Water Commission (CWC), Central Electricity Authority (CEA), and National Hydroelectric Power Corporation (NHPC). The dam was completed and commissioned between 2001 and 2002, with all generating units operational by 2003.
The project cost was approximately ₹5.6 billion, largely financed through Indian grants and concessional loans.

Structural and Technical Features

The Kurichu Dam is designed as a concrete gravity dam, constructed to exploit the steep hydraulic gradient of the Kurichu River.
Key technical specifications:

• Dam type: Concrete gravity dam
• River: Kurichu (tributary of the Manas River)
• Location: Gyalpozhing, Mongar District, Bhutan
• Height: ~55 metres above foundation level
• Length: ~285 metres
• Reservoir capacity: Around 30 million cubic metres
• Installed capacity: 60 MW (4 × 15 MW Francis turbines)
• Type of scheme: Run-of-the-river with small pondage
• Annual generation: Approximately 400–450 million kilowatt-hours (kWh)
• Commissioned: 2002–2003

The dam diverts water through an intake structure into a headrace tunnel leading to the underground powerhouse, where the turbines convert the river’s kinetic energy into electricity. The power is transmitted through high-voltage lines to eastern Bhutan’s regional grid and onward to India.

Hydroelectric Operation and Output

The Kurichu Hydroelectric Project (KHP) operates as a run-of-the-river scheme with limited storage, designed to ensure minimal submergence and environmental disturbance. The project’s electricity generation depends on seasonal river discharge, with maximum output during the monsoon months (June–September).
The plant supplies power to:

• Eastern Bhutan, including Mongar, Lhuentse, and Trashigang districts.
• The national grid, contributing to Bhutan’s domestic electrification goals.
• India, particularly to Assam and adjoining states, under the Bhutan–India energy export arrangement.

Economic and Strategic Importance

The Kurichu project holds immense economic importance for Bhutan’s development. Hydropower is the single largest contributor to Bhutan’s national income, providing over 35–40% of government revenue and forming the cornerstone of its export economy.
Key benefits of the Kurichu Dam include:

• Revenue generation through export of surplus power to India.
• Rural electrification and industrial development in eastern Bhutan.
• Infrastructure development, including access roads, bridges, and townships.
• Employment generation during construction and operation.
• Strengthening Bhutan–India bilateral cooperation, serving as a model of cross-border energy partnership.

The project exemplifies Bhutan’s “hydropower for prosperity” approach, balancing renewable energy generation with environmental and social responsibility.

Environmental and Social Considerations

As a run-of-the-river project, the Kurichu Dam causes minimal displacement and submergence compared to large reservoir projects. Nevertheless, environmental impact assessments (EIAs) were carried out before construction to mitigate potential effects on river ecology, sedimentation, and biodiversity.
Mitigation measures include:

• Maintenance of minimum environmental flow downstream to sustain aquatic life.
• Catchment area treatment to prevent erosion and siltation.
• Slope stabilisation and afforestation in surrounding areas.
• Limited relocation and compensation for small numbers of affected households.

The project also supports fish ladder systems and ecological monitoring to ensure sustainable river health.

Engineering and Environmental Challenges

The project’s location in the Himalayan seismic belt and high rainfall zone posed significant design and operational challenges. These included:

• High sediment loads during monsoon season, affecting turbine efficiency.
• Seismic safety considerations, requiring strong dam design and structural resilience.
• Landslides and flash floods, common in the steep Kurichu valley.
• Maintenance of transmission infrastructure in mountainous terrain.

In July 2004, exceptionally heavy monsoon rains triggered landslides and increased reservoir inflows, prompting the release of water from the dam and raising flood alerts downstream in Assam, India. This event underscored the importance of coordinated transboundary flood management between Bhutan and India.

Role in Bhutan–India Hydropower Cooperation

The Kurichu project represents one of the successful models of Bhutan–India hydropower collaboration, alongside other major projects such as Chukha (336 MW), Tala (1,020 MW), and Mangdechhu (720 MW).
The arrangement follows a grant–loan financing model, where India provides technical expertise and purchases surplus electricity at mutually agreed tariffs. In return, Bhutan gains infrastructure, energy independence, and foreign exchange earnings.
This partnership has strengthened bilateral relations and contributed to regional energy security and cross-border grid integration in South Asia.

Socio-Economic and Regional Development

The project has transformed the socio-economic landscape of eastern Bhutan. Improved electricity availability has boosted:

• Cottage industries and agro-processing units.
• Education and healthcare facilities, through rural electrification.
• Transport and communication infrastructure, connecting remote villages.

The development of Gyalpozhing town near the dam has become a model of planned urban growth supported by hydropower development.

Key Facts and Figures

Broader Significance

The Kurichu Dam stands as a symbol of sustainable hydropower development in the Himalayan region. It exemplifies Bhutan’s approach to integrating environmental care, economic growth, and regional cooperation under its guiding philosophy of Gross National Happiness (GNH).