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Which of the following are the most important reason/reasons of flood becoming a destructive natural hazard in the Ganga-Brahmaputra valley ? 1. Due to population pressure more and more people are living in flood prone areas 2. Increased frequency and magnitude of landslide and soil erosion in the upper catchments 3. Increase in the amount and intensity of rainfall in the north-western part of India Select the correct answer using the code given below:
Explanation
The Ganga-Brahmaputra valley is highly susceptible to destructive floods due to both natural and anthropogenic factors. Population pressure has forced more people to settle in flood-prone areas and riverine plains, increasing the vulnerability and destructive impact of annual floods [4]. In the upper catchments, heavy rainfall and tectonic activity lead to increased frequency and magnitude of landslides and soil erosion [1]. This causes heavy silting of the riverbeds, reducing their water-carrying capacity and exacerbating flood intensity [2]. While heavy rainfall is a primary cause, it is concentrated in the middle and lower reaches of the Brahmaputra and the eastern/northern parts of the Ganga basin [1]. Statement 3 is incorrect because the north-western part of India is generally a region of lower rainfall intensity compared to the eastern regions, and its rainfall patterns are not the primary driver for floods in the Ganga-Brahmaputra valley.
Sources
- [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > 2. The Brahmaputra River Basin > p. 49
- [4] https://cdn.downtoearth.org.in/dte/userfiles/images/soe3_20130618.pdf
- [2] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > Flood Prone Areas of India > p. 47