Dam failures are always catastrophic, especially on the downstream side, resulting in a colossal loss of life and property. Analyze the various causes of dam failures. Give two examples of large dam failures.
Approach ┬╖ directive: тАЬanalyse / giveтАЭ
What it asks ┬╖ Analyse the natural, technical and management causes behind dam failures and cite two large examples.
It asks 2 things тАФ answer each
- Analyse the various causes of dam failures: hydrological, structural, ageing, external and operational
- Give two examples of large dam failures
Open with ┬╖ India has 6,628 large dams, the world's third-largest stock, and about 26% are over 50 years old (PIB, 2026); a breach sends a flood wave downstream with almost no warning, so the valley below pays for every weakness above.
Cover
- Hydrological: overtopping when inflow exceeds spillway capacity; climate change makes old design floods obsolete.
- Structural and geotechnical: seepage and piping through embankment or foundation, weak rock, poor design or construction.
- Ageing and neglect: 291 dams over 100 years old; deteriorated concrete, silted reservoirs, jammed gates, weak inspection.
- External and operational: earthquakes, landslides into reservoirs, cascading failure; late gate operation, no emergency action plan.
- Examples: Machchhu-II, Morbi (11 August 1979), overtopping; Teton, USA (5 June 1976), piping during first filling.
- Way forward: Dam Safety Act 2021 (in force 30 December 2021), DRIP rehabilitation, Emergency Action Plans, real-time flood forecasting.
Close with ┬╖ Dam safety is disaster prevention in its purest form: design margins, honest inspection and rehearsed warnings cost a fraction of the relief that follows a breach, which is what the Dam Safety Act 2021 must now deliver dam by dam.
Add value (verified)
- PIB backgrounder (15 May 2026): India has 6,628 specified dams, the third-largest stock in the world; over 26% are more than 50 years old.PIB backgrounder: Dam Rehabilitation, Strengthening Infrastructure through Policy and Technology (15 May 2026) тЖЧтАЬIndia stands 3rd in terms of Large Dams worldwide, with 6628 Specified dams. Over 26% of dams are more than 50 years old, necessitating systematic rehabilitation and safety upgrades.тАЭ
- PIB (15 May 2026): 1,681 dams (26%) are over 50 years old, 291 over 100 years, and 42% are 25-50 years old.PIB backgrounder: Dam Rehabilitation, Strengthening Infrastructure through Policy and Technology (15 May 2026) тЖЧтАЬAbout 26% (1,681 dams) of these dams are more than 50 years old. This includes 291 that are more than 100 years old. About 42% fall within the 25тАУ50 years age bracket.тАЭ
- PIB (15 May 2026): the Dam Safety Act 2021 came into force on 30 December 2021 and covers surveillance, inspection, operation and maintenance of specified dams.PIB backgrounder: Dam Rehabilitation (15 May 2026), Institutional Framework тЖЧтАЬThe Dam Safety Act, 2021 came into force on 30 December 2021 and provides a comprehensive framework for surveillance, inspection, operation and maintenance of specified dams across the country.тАЭ
- ASDSO case study: Machhu Dam II failed on 11 August 1979 when water overtopped the earthen embankments on both sides of the masonry spillway.Association of State Dam Safety Officials, Dam Failures and Lessons Learned: Machhu Dam II (Gujarat, India, 1979) тЖЧтАЬIt was early afternoon on August 11, 1979 when water overtopped the earthen embankments on both sides of the masonry spillway leading to the failure of Machhu Dam II.тАЭ
- ASDSO case study: Teton Dam failed on 5 June 1976 during its first filling, killing 11 people and causing about $400 million in damage.Association of State Dam Safety Officials, Dam Failures and Lessons Learned: Teton Dam (Idaho, 1976) тЖЧтАЬthe dam experienced catastrophic failure on June 5, 1976 during its first filling. Failure of the Teton Dam and subsequent draining of the reservoir caused the deaths of 11 people and approximately $400 million in damages.тАЭ
Question: UPSC's CS (Main) 2023, GS Paper III тАФ paper тЖЧ. Approach: Minimalist IAS, checked 3 Oct 2026 (how we verify) тАФ UPSC publishes no model answers. ┬╖
Model answer┬╖ 223words ┬╖ Minimalist IAS
India has 6,628 large dams, the world's third-largest stock, about 26% over 50 years old (PIB, 2026); a breach gives the valley below almost no warning.
Causes of dam failures
- Hydrological: overtopping when inflow exceeds spillway capacity; climate-driven extreme rain makes old design floods obsolete.
- Structural: seepage and internal erosion (piping) through embankment or foundation, weak rock, poor construction.
- Ageing and neglect: 291 Indian dams are over 100 years old; worn concrete, silted reservoirs, jammed gates, weak inspection.
- External triggers: earthquakes, reservoir landslides, cascading failure down a chain of dams.
- Operational lapses: late gate operation, no emergency plan or downstream warning.
- Trigger (flood, quake)
- weakness (age, silt)
- breach
- flood wave
- downstream loss
Two large dam failures
- Machchhu-II, Morbi (1979): water overtopped the earthen embankments beside the masonry spillway on 11 August 1979 and swept into Morbi.
- Teton, USA (1976): failed on 5 June 1976 during first filling: seepage turned muddy, a sinkhole opened and piping breached the crest within hours, killing 11.
Way forward
- Institutions: the Dam Safety Act 2021 (in force 30 December 2021) mandates surveillance, inspection and maintenance of specified dams through national and state bodies.
- Practice: DRIP rehabilitation, Emergency Action Plans, flood forecasting, safety reviews.
Design margins, honest inspection and rehearsed warnings cost a fraction of post-breach relief; delivering them dam by dam is the Dam Safety Act's real test.
Prepared by Minimalist IAS to the answer standard of Shivam Singh (mentor, 7 years) ┬╖ facts checked against official sources (how we verify) ┬╖ updated 3 Oct 2026. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.
