Nature’s Warning: Floods

  • IASbaba
  • October 1, 2022
  • 0
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Context: There has been an increase in the magnitude, the frequency and the intensity of floods in many parts of the world. As an example, nearly a third of Pakistan is experiencing devastation in 2022, with a spread of diseases and severe shortage of potable water after intense flooding. In June 2022, Assam experienced one of its worst floods in living memory which affected over 30 districts. In some districts in Assam and Bihar, flooding is a recurrent feature.

What is the meaning of flood?

A high-water level that overflows the natural banks along any portion of a stream is called a flood. Thus, Floods are commonly associated with a stream or river.

What are the causes of Floods?

In general, there are two types of causes:

Natural Causes:

  • Heavy rainfall and cloud bursts – Heavy concentrated rainfall reduces the capacity of rivers to accept any more surface run–offs due to rainfall and as result water spills over to adjoining areas. These can cause extensive damage within short span of time.
  • Heavy melting of ice and snow,
  • Changes in river systems and large catchment areas,
  • Sediment deposition/Silting of river beds,
  • The collapse of dams,
  • Transgression of sea at the occasion of tropical cyclone, and
  • Tsunami in coastal areas and landslides in course of rivers

 Man-made/Anthropogenic causes

  • Deforestation – It leads to soil erosion and Landslides. It also leads to silting of river beds.
  • Unscientific use of land utilization and bad farming practices
  • Increased Urbanisation – It has reduced the ability of the land to absorb rainfall through the introduction of hard impermeable surfaces.
  • Concretisation of surface: it prevents excess surface water to percolate down the soil and recharge groundwater.
  • Climate change and pollution

What are the Consequences of Flood?

  • The crops get adversely affected by the temporary loss of the agricultural season and fertile soil cover.
  • It leads to changes and destruction of habitats, and loss of biodiversity
  • Disruption of the lines of rail, road communication, and essential services
  • Spread of water-borne and infectious diseases like cholera immediately after floods.
  • Floods in India account for over 40% of the deaths out of all natural disasters. Empirical studies have also shown that flood damage has a negative impact on economic growth in the long run and considerably reduces female employment opportunities in the agricultural sector.
  • Government data shows that between 1953 and 2019, on an average, floods claimed 1,653 lives every year and caused losses including the house, public property and crop damage of Rs. 3,612 crores every year.

 Flood distribution in India:

  • 125 of Indian land is flood-prone. State-wise study shows that about 27% of the flood damage in the country is in Bihar, 33% in Uttar Pradesh and Uttarakhand, and 15% by Punjab and Haryana.
  • The major flood areas in India are in the Ganges – Brahmaputra – Meghna Basin which accounts for nearly 60% of the total river flow of the country.
    • Distribution of flood plains
    • Brahmaputra River Region
    • Ganga River Region
    • North – West River Region
    • Central and Deccan India
  • The middle and lower courses of North Indian rivers such as Ganga, Brahmaputra, Kosi, Damodar, Mahanadi, etc. Are prone to floods due to very low gradient. The flat plains do not have enough gradients for the outlet of drainage.
  • Parts of the Eastern coasts of India are particularly prone to cyclones accompanied by strong winds, storm surges, tidal waves, and torrential rains.

Flooding due to cross-border rivers:

On sharing of information:

  • Flooding is compounded by the lack of transparency in the sharing of hydrological information and also information relating to activities that are transboundary in their effect, thus serving as an obstacle in understanding the magnitude of flooding.

On customary international law:

  • In accordance with customary international law, no state has to use its territory in a manner that causes harm to another state while using a shared natural resource.
  • This obligation gives rise to other procedural norms that support the management of floods, which include notification of planned measures, the exchange of data and information, and also public participation.

 The Brahmaputra and India’s concerns

  • China’s excessive water release, as a “dam controller”, in violation of customary international law has the potential to exacerbate flooding in Assam in future.
  • India’s main concern is that there is no comprehensive sub-basin or all basin-level mechanism to deal with water management of Brahmaputra.
    • Neither India or China are party to the United Nations Convention on the Law of the Non-Navigational Uses of International Watercourses (UNWC) 1997 or the United Nations Economic Commission for Europe (UNECE) on the Protection and Use of Transboundary Watercourses and International Lakes 1992 (Water Convention).
  • In the absence of any mechanism, India relies on its memorandum of understanding (MoU) with China in 2013 with a view to sharing hydrological information during the flood season. The MoU does not allow India access to urbanisation and deforestation activities on the Chinese side of the river basin.

India, Nepal and flood prevention:

  • Floods are also a recurrent problem in the Koshi and Gandak river basins that are shared by India and Nepal.
    • The intensity and magnitude of flooding is rising because of heavy seasonal precipitation as well as glacial retreat due to global warming and human-induced stressors such as land use and land cover changes in the river basin area of Nepal (Terai) and Bihar.

Way forward:

  • In contravention of procedural customary international law obligation, India considers data on transboundary rivers as classified information, which is one of the key challenges in developing cross-border flood warning systems.
  • In light of the cataclysmic floods in Pakistan and the visible effects of climate change, it is important that all riparian states must comply with all the procedural duties pursuant to the no harm rule. They must also think of becoming a party to either the UNWC or the UNECE Water Convention.

MUST READ: Urban Floods            

Source: The Hindu

Previous Year Question

Q.1) Gandikota canyon of South India was created by which one of the following rivers ? (2022)

  1. Cauvery
  2. Manjira
  3. Pennar
  4. Tungabhadra

Q.2) Consider the following pairs:

Reservoirs        :     States

Ghataprabha   :     Telangana

Gandhi Sagar  :     Madhya Pradesh

Indira Sagar    :     Andhra Pradesh

Maithon           :     Chhattisgarh

How many pairs given above are not correctly matched? (2022)

  1. Only one pair
  2. Only two pairs PAY
  3. Only three pairs
  4. All four pairs


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