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: “analyse / give”
What it asks · Analyse the natural, technical and management causes behind dam failures and cite two large examples.
The question has 2 parts — answer each
- Analyse the various causes of dam failures: hydrological, structural, ageing, external and operational
- Give two examples of large dam failures
Open with · A dam breach releases a flood wave with little warning, so the downstream valley bears the worst of it.
Cover
- Hydrological: overtopping when an extreme flood exceeds spillway capacity, made likelier by intense rainfall and climate change.
- Structural and geotechnical: seepage and piping through the embankment or foundation, weak foundations, and poor design or construction quality.
- Ageing and neglect: deteriorated concrete, silted reservoirs, faulty gates and outlets, and weak inspection and maintenance.
- External triggers: earthquakes, landslides into the reservoir, and cascading failure in a chain of dams.
- Operational lapses: delayed gate operation, no early-warning or emergency action plan, and poor reservoir regulation.
- Examples: Machchhu-II dam, Morbi (Gujarat, 1979), overtopped in heavy rain; Teton dam (USA, 1976), which failed through piping while first being filled.
- Remedies: Dam Safety Act 2021 with national and state authorities, periodic safety review, Emergency Action Plans, DRIP rehabilitation and real-time flood forecasting.
Close with · Prevention lies in design margins, regular inspection and tested emergency plans, not only in post-disaster relief.
Question: UPSC's CS (Main) 2023, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 202 words (UPSC limit 150) · Minimalist IAS
A dam breach releases a flood wave with almost no warning, and the downstream valley bears the worst of it.
Causes of dam failure
- Hydrological: overtopping when a flood exceeds spillway capacity; extreme rainfall under climate change makes older design floods obsolete.
- Structural and geotechnical: seepage and piping through the embankment or foundation, weak foundation rock, and poor design or construction quality.
- Ageing and neglect: deteriorated concrete, silted reservoirs that shrink the flood cushion, jammed gates and outlets, and weak inspection and maintenance.
- External triggers: earthquakes, landslides into the reservoir that send waves over the crest, and cascading failure down a chain of dams.
- Operational lapses: delayed gate operation, no emergency action plan or downstream warning, and poor reservoir regulation during the monsoon.
Two large failures
- Machchhu-II dam, Morbi, Gujarat (1979): overtopped in heavy rain, sending a wall of water into Morbi town.
- Teton dam, USA (1976): failed through piping while the reservoir was being filled for the first time.
Lessons
- The Dam Safety Act 2021 creates national and state authorities; periodic safety reviews, Emergency Action Plans, DRIP rehabilitation and real-time flood forecasting must follow.
Prevention lies in design margins, regular inspection and rehearsed emergency plans, not in relief after the flood.
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.