How will the melting of Himalayan glaciers have a far-reaching impact on the water resources of India?
Approach · directive: “how”
What it asks · Explain how glacier retreat alters river flows, floods, hydropower and water availability in India, in the short run and the long run.
The question has 2 parts — answer each
- Explain how glacier retreat changes river flows: more water first, less later, and a lost dry-season buffer
- Explain the far-reaching consequences: hazards, hydropower, irrigation, groundwater, ecosystems and shared rivers
Open with · Himalayan glaciers and snowfields feed the Indus, Ganga and Brahmaputra systems, so their retreat affects the water security of hundreds of millions of people.
Cover
- Flow pattern: melt first raises flows and flood risk, then cuts dry-season flow once glaciers shrink, hitting glacier-fed rivers such as the Indus most.
- Seasonality: lean-season flows that support irrigation and drinking water in the Indo-Gangetic plain become less reliable; monsoon-fed rivers are affected less.
- Hazards: glacial lake outburst floods and ice–rock avalanches, such as Chamoli (2021) and South Lhonak in Sikkim (2023), destroy hydropower assets and settlements.
- Hydropower and irrigation: Himalayan projects and canal-irrigated farming depend on steady melt; uncertain flows raise groundwater pressure and energy risk.
- Wider effects: shifting flows strain water sharing with neighbours on shared rivers, and hurt wetlands, fisheries and mountain livelihoods.
- Response: glacier monitoring, GLOF early warning, watershed management, efficient irrigation and the National Mission for Sustaining the Himalayan Ecosystem.
Close with · Managing the shift from more water now to less later needs monitoring, disaster preparedness, efficient water use and regional cooperation.
Question: UPSC's CS (Main) 2020, GS Paper I — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 226 words (UPSC limit 150) · Minimalist IAS
Himalayan glaciers and snowfields feed the Indus, Ganga and Brahmaputra, whose basins support hundreds of millions of people; as the ice retreats, both the volume and the timing of that water change.
Changing river flows
- Peak water, then decline: faster melt swells rivers and flood risk for some decades; once the ice store shrinks, flows fall, hitting the melt-dependent Indus hardest.
- Lost dry-season buffer: glaciers release water in the hot months before the monsoon, so lean-season supply for drinking water and rabi irrigation in the Indo-Gangetic plain turns erratic; monsoon-fed peninsular rivers are affected far less.
- Flashier rivers: rain replacing snow means sharper floods, heavier silt loads and less natural storage in the mountains.
Far-reaching consequences
- Hazards: growing glacial lakes bring outburst floods and ice-rock avalanches; Chamoli (2021) and the South Lhonak lake burst in Sikkim (2023) wrecked hydropower projects and settlements.
- Hydropower and irrigation: run-of-river projects and canal commands built for steady melt face uncertain flows, pushing farmers towards groundwater and raising energy risk.
- Shared waters and ecosystems: shifting flows strain water-sharing with neighbours on all three river systems and starve wetlands, fisheries, springs and mountain livelihoods.
India must manage a shift from too much water to too little: glacier monitoring, GLOF early warning, spring and watershed management, efficient irrigation and basin cooperation under the National Mission for Sustaining the Himalayan Ecosystem are the tools.
Written by Minimalist IAS from facts checked at source (how we verify) — a little fuller than exam length, so every part of the question is covered; in the hall, keep the structure and trim the detail. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.