indias-flood-map

Context: Recent occurrences of heavy rainfall leading to flooding across India have shown that flood-prone areas in the country go beyond those mentioned in the central monitoring map. 

  • As of July 23, 70 people in Maharashtra had died due to landslides and other flood-related events covering seven districts. 

Flood prone areas of India

  • Rashtriya Barh Ayog (RBA), or the National Flood Commission, was set up by the Ministry of Agriculture and Irrigation in 1976, to study India’s flood-control measures after the projects launched under the National Flood Control Programme of 1954 failed to achieve much success.
  • In 1980, the RBA made 207 recommendations and four broad observations. 
  • The RBA estimated that the total area vulnerable to floods in 1980 was around 40 million hectares.
    • The figure was reached by calculating the maximum area affected by floods in all states in any one year between 1953 and 1979, and adding to it the area where flood protection works had been undertaken.
    • The areas where protection works failed were then subtracted from the total. It is, however, a flawed methodology and National Flood Commission itself acknowledges it.
  • According to the National Disaster Management Authority (NDMA), the area lies mostly along the Ganga-Brahmaputra river basin.
    • It lies from the northern states of Himachal Pradesh and Punjab, covering Uttar Pradesh and Bihar and stretching to Assam and Arunachal Pradesh in the northeast. 
    • The coastal states of Odisha and Andhra Pradesh, parts of Telangana and Gujarat also witness yearly floods.

Concerns

  • Demarcation based on old data: This demarcation, however, is based on estimates made in 1980 by Rashtriya Barh Ayog (RBA) or National Flood Committee formed four-decades ago. 
    • Around 40 million hectares of geographical area in India is vulnerable to floods, according to the body. 
  • Ignoring climate change: RBA also ascribed the floods to purely anthropogenic factors and not heavy downpours. 
    • First, it said there was no increase in rainfall in India and, thus, the increase in floods was due to anthropogenic factors such as deforestation, drainage congestion and badly planned development works.
  • The effectiveness of the methods adopted to control floods, such as embankments and reservoirs. RBA suggested that the construction of these structures be halted till their efficacy was assessed.
  • The very definition of flood-prone area does not reflect the effectiveness of the flood management works undertaken. It is clear that while the maximum area flooded in any one year may broadly indicate the degree of the flood problem in a state, it does not strictly indicate the area liable to floods as different areas may be flooded in different years.
    • Despite its flaws, the old method continues to be used. India began collecting data for a more scientific assessment — one that relies on frequency-based climate modelling
  • The RBA report also recognised the need for timely evaluation of flood management projects. It entrusted state irrigation and flood control departments, CWC, Ganga Flood Control Commission and the Brahmaputra Board with the task of adopting or discarding them on the basis of their performance. But this has not been the case.

Case for updating flood map of India

  • Over the last four decades, India has been reeling from the effects of climate change like many parts of the world. The global rise in temperatures has led to large periods of no rain followed by extreme precipitation, an observation which is becoming a trend. 
  • Excess rainfall: Extreme rainfall events have tripled in central India between 1950 and 2015, according to the science journal Nature
    • Climate change is leading to extreme rains in a shorter period of time leading to floods. There will be a rise in the frequency of floods in India due to rise in temperatures between 2070 and 2100, according to Climate Change and India: A 4x4 Assessment, a report by the Union Ministry of Environment and Forest.
  • The flood-prone states in India have not identified or demarcated affected areas in spite of recommendations by multiple committees, a report by the Comptroller and Auditor General of India (CAG) has found. 
  • Drainage and embankments are included in the State List in the Constitution, thus implementation of related schemes is the state’s responsibility. The Centre’s role is advisory in nature.
  • Recommendations of the Rashtriya Barh Aayogh (RBA), which was constituted to identify flood-prone areas to reduce annual damage, were sent to states and union territories (UTs) in 1981, yet many of those have not been acted upon.
    • As per RBA’s recommendations, this data was to be used for drawing maps of areas affected by floods, and further verify it after field visits. These have, however, not been implemented.
  • The National Water Policy of 2012, formulated by the Ministry of Water Resources, specified preparation of digital elevation models and frequency-based Flood inundation maps have not been prepared. The policy also stipulated morphological studies of 301 rivers in the 11 states that lie in the Ganga Basin. 

An accurate estimate is crucial for framing flood management programmes. At least 43 years after India’s first and last commission on floods was constituted, there is no national-level flood control authority in the country so far. The shift in the flooding patterns and frequencies demands India to come up with an updated map of flood-prone areas factoring in the impacts of climate change 

Source: https://www.downtoearth.org.in/news/climate-change/it-s-been-40-years-update-india-s-flood-map-now-78166