Dealing with a deluge

Context:

As floods swamp Hyderabad, the focus is on the inadequacy of drainage infrastructure

Relevance:

  1. GS Paper 1: Urbanization
  2. GS Paper 3: Disasters & Disaster Management

Mains Questions:

  1. The frequency of urban floods due to high intensity rainfall is increasing over the years. Discussing the reasons for urban floods. highlight the mechanisms for preparedness to reduce the risk during such events. (15 marks)
  2. The effects of flooding due to deluges can only be mitigated if urban planners take into account the hydro-geology of cities and ensure that construction, development and land occupation do not take place in a way that reduces the area of wetlands. Elaborate (15 marks)

1: What is disaster?

“Disaster is an undesirable occurrence resulting from forces that are largely outside human control, strikes quickly with little or no warning, which causes or threatens serious disruption of life and property including death and injury to a large number of people, and requires therefore, mobilisation of efforts in excess of that which are normally provided by statutory emergency services”.

2: What is flood?

Flood is Inundation of land and human settlements by the rise of water in the channels and its spill-over. Floods occur commonly when water in the form of surface run-off exceeds the carrying capacity of the river channels and streams and flows into the neighbouring low-lying flood plains.

3: What are the causes of flood in India?

Flood is a natural phenomena but recent times anthropogenic factors are more responsible for flood in India.

Natural causes of flood:-

  • Floods can be caused due to a storm surge (in the coastal areas).
  • High intensity rainfall for a considerably longer time period.
  • Melting of ice and snow.
  • Reduction in the infiltration rate and presence of eroded material in the water due to higher rate of soil erosion.

Anthropogenic causes of flood: Human beings play an important role in the genesis as well as spread of floods.

  • Indiscriminate deforestation
  • Unscientific agricultural practices.
  • Disturbances along the natural drainage channels and colonisation of flood-plains and river-beds.
Flood UPSC Legacy IAS

Causes of recent flood in Hyderabad:  Construction over lake beds and encroachments of drainage channels have been identified as problems that have exacerbated flooding and inundation in the city in the past.

4: Geographical distribution of flood in India: Rashtriya Barh Ayog (National Flood Commission) identified 40 million hectares of land as flood-prone in India.

  • Assam, West Bengal and Bihar are among the high flood-prone states of India.
  • Most of the rivers in the northern states like Punjab and Uttar Pradesh, are also vulnerable to occasional floods.
  • States like Rajasthan, Gujarat, Haryana and Punjab are also getting inundated in recent decades due to flash floods. This is partly because of the pattern of the monsoon and partly because of blocking of most of the streams and river channels by human activities.
  • Sometimes, Tamil Nadu experiences flooding during November – January due to the retreating monsoon.
INDIA AREA LIABLE TO FLOODS AKISTAN INDIAN Area Liable to Flood CHINA TIBET UPSC Legacy IAS BENGAL OCEAN

5: What are the consequences of flood in India?

  • Frequent inundation of agricultural land and human settlement, particularly in Assam, West Bengal, Bihar and Eastern Uttar Pradesh (flooding rivers), coastal areas of Odisha, Andhra Pradesh, Tamil Nadu and Gujarat (cyclone) and Punjab, Rajasthan, Northern Gujarat and Haryana (flash floods) have serious consequences on the national economy and society.
  • Floods do not only destroy valuable crops every year but these also damage physical infrastructure such as roads, rails, bridges and human settlements.
  • Millions of people are rendered homeless and are also washed down along with their cattle in the floods.
  • Spread of diseases like cholera, gastro-enteritis, hepatitis and other water-borne diseases spread in the flood-affected areas.
  • Positive contribution:-  Every year, floods deposit fertile silt over agricultural fields which is good for the crops. Majuli (Assam), the largest riverine island in the world, is the best example of good paddy crops after the annual floods in Brahmaputra.

6: Measures to control the flood in India:

Measures to control the flood in India UPSC Legacy IAS
  • Construction of flood protection embankments in the flood-prone areas, construction of dams, afforestation and discouraging major construction activities in the upper reaches of most of the flood-creating rivers, etc. are some steps that need to be taken up on urgent basis.
  • Removal of human encroachment from the river channels and depopulating the flood plains can be the other steps.
  • Cyclone centres may provide relief in coastal areas which are hit by a storm surge.
  • Flood Plain Zoning: It is to regulate land use in the flood plains in order to restrict the damage due to floods, while deriving maximum benefits from the same.
  • Integrated Water Resources Management aiming at integrating management of water resources at the basin or watershed scale.
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