18 May 2024 : Daily Answer Writing
Q1) How will you explain that the anthropogenic factors enhance the intensity, increase the frequency, and amplify the impacts of natural disasters? Substantiate your answers with suitable examples.
(150 Words/10 Marks)
Flood is a natural phenomenon associated with rivers. It occurs when water flow exceeds the river’s channel capacity, breaching the natural levees, entering the floodplains. According to Bihar State Disaster Management Authority, 73.63% of North Bihar is considered to be flood prone.
Factors of vulnerability for the annual mayhem of floods in Bihar:
- Natural factors:
- a) Rivers: Bihar has vast network of rivers and tributaries which are youthful in theupper reaches and carry huge volume of water.
E.g., Ganges, Gandak, Baghmati, Mahanandha etc.
- b) Monsoon: The state lies closer to the foothills of Himalayas which act as an orographic barrier to monsoonal winds leading to heavy downpours in catchment areas.
E.g., half of the world’s 8km plus peaks lies in Kosi’s catchment area.
- c) The Himalayas is composed of younger rocks which are more prone to erosion and results in formation of high loads of sediments.
- d) The relatively flat topography of Bihar cannot provide sufficient slope for the rivers which forces them to suddenly reduce their speed and the river spreads laterally. Further, highly meandering river change course annually, resulting in flooding.
E.g., Kosi river shifted 100 km leftward in the past 200 years.
- Anthropogenic factors:
- a) Deforestation: The conversion of forests to agricultural and pastoral land resulted in loss of buffering effect of the forests. E.g., Nearly 85% of the state’s land is under cultivation.
- b) Encroachment: Due to increasing population, people started occupying the flood plain for settlement and agriculture, leading to increased vulnerability to floods.
- c) River development:
- Apart from natural siltation, construction of dams and reservoirs resulted in increased siltation.
E.g., Allegations that Farakka barrage results in siltation and leading to flood.
- Construction of embankments, although provides temporary relief, however increases the capacity of channel to hold water and accentuates the vulnerability to flood.
- d) Climate change: The accelerated pace of global warming has resulted in unprecedented increase in frequency and intensity of Extreme Rainfall Events, increasing the water flow in rivers.
Sustainable strategy for flood risk management can be ensured through following measures:
- Structural measures:
- a) Detention Basins: Revival and improvements of chaurs or detention basins.
- b) Embankments: Strengthening, regular maintenance and repair of these embankments must be done regularly.
- c) Channel Improvement practices like dredging and desiltation increase the channel capacity.
- Functional measures:
- a) Strengthening the framework of Bihar’s SDMA through increased funds and functionaries to mitigate disasters.
- b) Reviving inland waterways could lead to better maintenance of canals through economical ways of maintaining river basins.
E.g., regular desilting; deeper channels.
- Watershed approach:
- a) Reviving the natural retention capacity of the river basin.
E.g., prevention of excessive sand mining; enhancing ground water levels.
- b) Restricting illegal encroachment on floodplains by delimitating flood hazard zone.
- c) Afforestation measures to ensure presence of natural barriers against flood hazards.
- d) International cooperation with Nepal to share details on hydro-metrological data.
Flood risk management of Bihar warrants multipronged approach through convergence of various stake holders such as Centre, neighboring states, Nepal and community participation to achieve sustainable solutions.
