Tehri Dam

Tehri Dam
Name	Tehri Dam
Location	Tehri, Uttarakhand, India
Status	Operational
Construction began	1978
Opening	2006
Owner	Uttarakhand Jal Vidyut Nigam Limited
Dam type	Rock and Earth-fill with upstream concrete face
Height	260.5 m
Length	575 m
Reservoir name	Tehri Reservoir (Tibetan Lake)
Reservoir capacity total	3.54 km³
Plant capacity	1,000 MW (initial 100 MW units; later stages 1,000 MW combined)

Tehri Dam Tehri Dam is a multi-purpose dam on the Bhagirathi River near Tehri in Uttarakhand, India, developed for hydropower, irrigation, and municipal water supply. The project involved large-scale civil engineering, energy planning, and socio-environmental management, with involvement from national and international agencies. It remains one of South Asia's tallest dams and a focal point of debates over development, relocation, and ecology.

History

The project's origins trace to early post‑independence river development studies by the Central Water Commission, Indian Engineers, and planners influenced by policies from the Planning Commission of India and ministers in the Ministry of Power (India). Initial proposals from the 1960s culminated in surveys and clearances under administrations including the Indira Gandhi government and later cabinets led by Rajiv Gandhi and Atal Bihari Vajpayee. Construction began under state and central coordination in 1978 with contributions from firms such as National Hydroelectric Power Corporation and consultants linked to the World Bank and engineering houses advising on dams like Bhakra Dam and Hirakud Dam. Opposition movements featuring activists including Sunderlal Bahuguna and organizations like the Chipko Movement and Save Tehri campaigned on displacement and ecological grounds, prompting legal actions in the Supreme Court of India and sustained media coverage by outlets such as The Hindu and The Times of India. Major milestones included incremental commissioning of facilities and final filling phases under administrations connected to the Uttar Pradesh state government (before Uttarakhand's creation) and the later Uttarakhand (state) administration.

Design and Construction

The design combined a rock and earth‑fill embankment with an upstream concrete face influenced by technologies used in projects like Koyna Dam and international precedents such as Three Gorges Dam (design lessons) and Hoover Dam (structural comparisons). Engineering contracts were awarded to consortia including Indian public sector units and private contractors experienced from projects like Narmada Dam and Sardar Sarovar Project. Construction phases encompassed foundation excavation near the confluence of the Bhagirathi River and tributaries, diversion works, cofferdams, and placement of zoned materials with instrumentation for seepage and settlement monitoring comparable to instrumentation regimes at Itaipu Dam. Rehabilitation and resettlement planning referenced models from Tehri Garhwal district administrations and international resettlement practice.

Specifications and Engineering

The dam is a 260.5 m high, 575 m long rock and earth‑fill embankment with an upstream concrete face and a crest designed for flood passage akin to spillways at Bhakra Nangal Dam. The reservoir stores approximately 3.54 km³, with active storage calibrated for run‑of‑river and seasonal regulation similar to storage operations on the Ganges basin. The hydropower complex includes underground powerhouse caverns housing turbines and reversible pump‑turbines for pumped storage concepts studied alongside projects like Bath County Pumped Storage Station. Penstocks, surge shafts, and tailrace tunnels were engineered drawing on tunneling practices from the Chamera Hydroelectric Project and Rihand Dam, using rock reinforcement methods and grouting techniques employed in Himalayan geology projects.

Reservoir and Hydrology

The reservoir inundated valleys of the Bhagirathi River and tributaries, altering seasonal flow regimes downstream toward confluences at Devprayag and impacts extending into the Ganga Basin. Hydrological planning incorporated monsoon variability data used by the India Meteorological Department and river basin modeling approaches found in studies of the Upper Ganges Basin. Sedimentation forecasts and catchment conservation measures paralleled interventions from catchment projects in the Alaknanda sub‑basin and riparian afforestation programs promoted by the National Afforestation Programme.

Power Generation and Irrigation

The installed power capacity was developed to provide peaking and base load generation, integrating with the northern grid managed by Power Grid Corporation of India and contributing to state demand in Uttarakhand and neighboring states like Uttar Pradesh and Haryana. Generation units, control systems, and switchyards employed technologies comparable to those in units supplied to projects such as Khardah and Koyna stations. Irrigation components were planned to augment water supply for downstream command areas in the Kumaon and Garhwal regions and to provide municipal water to urban centers including Dehradun and Rishikesh.

Environmental and Social Impact

The project caused large‑scale resettlement affecting communities from Tehri Garhwal district and altering land use patterns; rehabilitation programs involved state agencies, nongovernmental organizations, and public interest litigants such as those represented before the Supreme Court of India. Environmental impacts included habitat loss affecting Himalayan flora and fauna recorded in inventories by institutions like the Wildlife Institute of India and the Botanical Survey of India, with concerns about seismicity in a tectonically active zone studied by the Geological Survey of India and academics from universities such as IIT Roorkee and Banaras Hindu University. Biodiversity assessments referenced species lists similar to those monitored in Jim Corbett National Park and landscape connectivity issues addressed by conservation groups.

Safety, Maintenance and Controversies

Safety protocols include instrumentation monitoring, emergency action planning coordinated with district administrations and agencies like the National Disaster Management Authority (India), and maintenance regimes for tunnels and mechanical systems using contractors experienced from projects like Teesta V and Rangit. Controversies encompass debates on seismic risk assessments presented by researchers associated with institutions such as IIT Kanpur, litigation outcomes from the Supreme Court of India, and public protests covered by national media outlets. Ongoing scrutiny concerns water allocation disputes involving state ministries, operational transparency, and long‑term environmental monitoring by bodies including the Central Electricity Authority and conservation NGOs.

Category:Dams in Uttarakhand Category:Hydroelectric power stations in India