Multipurpose Dams in India: Benefits, Concerns and UPSC Notes (UPSC Environment)

Multipurpose dams are the single largest infrastructure class on India’s rivers. Of the roughly 6,000 large dams the country maintains, a significant share is designed to serve irrigation, hydroelectric power, drinking water supply, flood moderation, navigation and fisheries from the same reservoir. These structures are central to any UPSC discussion on water resources, renewable energy, disaster management and displacement. They are also among the most contested pieces of infrastructure after the 2023 Teesta-III dam collapse in Sikkim put dam safety back on the national agenda.

What is a multipurpose dam

A multipurpose dam is a hydraulic structure that simultaneously delivers two or more services. The classic Indian examples are Bhakra-Nangal on the Sutlej (power, irrigation, flood control), Hirakud on the Mahanadi (irrigation, power, flood control), Nagarjuna Sagar on the Krishna (power, irrigation), Sardar Sarovar on the Narmada (power, irrigation, drinking water) and Tehri on the Bhagirathi (power, irrigation, drinking water). They are distinguished from single-purpose reservoirs by having separate outlets and operating rules for each service.

How hydropower works

Hydropower converts the potential energy of falling or fast-flowing water into mechanical energy through turbines and then into electricity through generators. Globally, hydropower accounts for about 15 percent of total electricity generation, the largest share among renewables. India's installed hydro capacity stood at around 47 GW in 2024, out of an identified potential of 1,45,320 MW, which means roughly two-thirds of the country's hydro potential is still unexploited.

Benefits of multipurpose dams

Renewable and low-carbon

Hydropower uses the natural water cycle, never runs out of fuel and releases no direct combustion emissions. It is the only grid-scale renewable that also provides inertia and frequency support, which makes it critical as India integrates large volumes of solar and wind into the grid.

Operational flexibility

Hydro plants ramp up from zero to full load in minutes, which makes them ideal balancing resources for intermittent renewables. Pumped Storage Projects act as giant grid batteries, storing surplus solar energy during the day and releasing it during evening peaks. India targeted 60 GW of pumped storage by 2030 under the 2023 draft PSP framework.

Multi-service dividends

• Irrigation in a fully developed command area.
• Assured drinking water supply to downstream cities.
• Flood moderation during monsoon peaks.
• Groundwater recharge in irrigated areas.
• Fisheries and Ramsar-recognised wetland habitats, such as Pong and Harike.
• Tourism, water sports and navigation.

Cost competitiveness

Once built, hydro plants have low operating costs, few moving parts and design lifetimes of 50 to 100 years, yielding very low levelised cost of electricity compared to thermal alternatives.

Concerns with multipurpose dams

Dam failure and safety risks

Large dams store enormous volumes of water. Structural defects, earthquakes, sabotage or extreme inflows can trigger catastrophic failures. The Morbi dam collapse of 1979, the 2021 Raini flash flood near Rishiganga and the October 2023 Lhonak Lake outburst that destroyed the Teesta-III dam in Sikkim show how quickly a design failure becomes a disaster. The Mullaperiyar Dam dispute between Kerala and Tamil Nadu is a live example of how ageing structures become federal flashpoints.

Reservoir-induced seismicity

The impoundment of large water bodies alters stress regimes in underlying rock. The 1967 Koyna earthquake of magnitude 6.3 remains the classic example in India; other suspected cases include Idukki and Srisailam. The phenomenon has renewed importance because most unexploited Himalayan hydro potential lies in high-seismicity zones.

Methane emissions

Contrary to the "zero emissions" image, tropical reservoirs emit methane from anaerobic decay of submerged biomass. Studies in the Amazon and some Indian reservoirs put lifecycle emissions of poorly planned hydro projects comparable to natural gas plants.

Ecosystem damage

• Submergence of forest, riverine valleys, marshland and grasslands rich in biodiversity.
• Disruption of fish migration, especially for hilsa and mahseer.
• Sediment trapping that starves deltas, accelerating coastal erosion in the Ganga-Brahmaputra, Godavari and Krishna deltas.
• Intermittent turbine releases that cause "hydropeaking," damaging downstream ecology.

Displacement and rehabilitation

The World Commission on Dams in 2000 estimated that dams had displaced 40 to 80 million people globally. India's own figure for Sardar Sarovar alone exceeds 3,20,000. Displacement is disproportionately borne by Scheduled Tribes, whose Forest Rights Act claims often remain unsettled at the time of submergence.

Project delays and command area gaps

• Substantial time and cost overruns are the norm. The Polavaram Project has crossed multiple deadlines since 2004.
• Lack of command-area development means promised irrigation potential remains unrealised for decades.
• Waterlogging and soil salinity along canals degrade otherwise productive farmland.

Dam safety framework in India

The Dam Safety Act, 2021 is the cornerstone legislation. It mandates:

• National Committee on Dam Safety (NCDS) and National Dam Safety Authority (NDSA) at the Centre.
• State Committee on Dam Safety and State Dam Safety Organisation for every state that owns large dams.
• Periodic inspection, instrumentation, emergency action plans and hydrological review for every specified dam.
• Criminal liability for wilful neglect.

The Central Water Commission runs the Dam Rehabilitation and Improvement Programme (DRIP) Phase II, which aims to rehabilitate 736 dams across 19 states with World Bank co-financing.

Way forward

• Mandatory cumulative impact assessment for cascade dams, especially in the Himalayas and Western Ghats.
• Climate-resilient design that accounts for glacial lake outburst floods, extreme rainfall and increased sediment loads.
• Transparent, time-bound and livelihood-restoring rehabilitation, not just one-time compensation.
• Restoration of environmental flows, downstream of every dam, as per the Draft National Water Policy.
• Pumped storage and run-of-river designs where feasible, to avoid large submergence.
• Decommissioning protocols for end-of-life dams, a policy gap in India.

Latest developments (2024-26)

• Teesta-III disaster, October 2023: The South Lhonak Lake glacial lake outburst flood destroyed the 1,200 MW Teesta-III dam, killed over 90 people and raised questions on hydro-project siting in glacial zones.
• Dam Safety Act implementation, 2024: The NDSA issued binding dam safety review protocols and initiated the first round of specified-dam inspections.
• Pumped Storage Push: The Ministry of Power's 2023 framework for pumped storage projects had, by early 2026, led to about 25 GW of PSP in various stages of bidding and construction, including Greenko's Pinnapuram project.
• Great Nicobar Project cleared environmental hurdles despite warnings from the Parliamentary Standing Committee (2024) on seismic and ecological risk of associated reservoirs.
• The revised Hydro Purchase Obligation (HPO) of 2023 requires discoms to source a minimum share of electricity from large hydro, supporting the commercial case for new multipurpose reservoirs.
• India's climate pledge at COP29 in Baku (2024) reiterated that hydropower is central to the 500 GW non-fossil capacity target for 2030.

UPSC Relevance

Prelims focus

• Major multipurpose projects and their rivers: Bhakra-Nangal (Sutlej), Hirakud (Mahanadi), Sardar Sarovar (Narmada), Nagarjuna Sagar (Krishna), Tehri (Bhagirathi), Rihand (Son), Indira Sagar (Narmada).
• Ramsar-recognised reservoir wetlands: Pong Dam Lake, Harike, Loktak, Renuka.
• Dam Safety Act, 2021: NCDS, NDSA, SCDS, SDSO.
• Pumped Storage Projects and Hydro Purchase Obligation.

Mains focus (GS III)

Frequent question framings cover the case for and against big dams in an era of climate change, the adequacy of India’s dam safety regime after Teesta-III, the reconciliation of hydropower expansion with biodiversity and tribal rights, and whether pumped storage can replace new greenfield dams. Answers should cite the Dam Safety Act, the World Commission on Dams framework, the Mihir Shah Committee and specific case studies.

Linkages

Multipurpose dams connect to the Forest (Conservation) Amendment Act 2023 (for diversion of forest land), the Biological Diversity Amendment Act 2023 (for biodiversity clearance), the Right to Fair Compensation Act 2013 (for rehabilitation), and India's updated Nationally Determined Contributions after COP29.