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Content

• Introduction
• Main Causes of Urban Floods
• Consequences

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Introduction

• Recent instances of floods such as the one in Bengaluru in Sep 2022, Chennai in 2015 and Mumbai in 2005 illustrate the increasingly vulnerability of Indian cities to this disaster. A complex set of factors have worked together to deteriorate the condition of our cities and increase their susceptibility to this devastation.

Main Causes of Urban Floods

i. Unplanned Urban Development:

• NDMA Report: Increasing Concretization of city land reduced the seepage of water in the ground and has increased the runoff.
• Loss of Natural flood storage in urban areas by filling of ponds and lakes to reclaim land for development.
  •  For instance, in Chennai the number of water bodies have come down to less than50 from 600 in 1980s. This became a major cause of 2015 floods.
  • Similarly, Bengaluru had 1,452 water bodies in 19th century, this has now reduced to only 193 lakes.
  • Here about 10,787 acres of lakes worth Rs 1.5 lakh crore has been encroached upon.
• Encroachment of Flood Plains of the rivers have led to loss of natural flood storage.
  • 2013 Uttarakhand floods
• Rapid urbanization has led to massive changes in land use patterns, as residential areas had sprung up in farmlands.

i. Improper and Inadequate Drainage system

• A lot of sewerage and drainage network is old and lack volume to carry flood water.
  • For e.g. The current drainage system of Delhi is based on the 1976 master plan.
• Poor Desilting and blockage of drainage systems. This was the main reason for 2005 Mumbai floods and a major factor in Sep 2022 Bengaluru floods.
  • Improper Waste Management leads to a lot of solid waste blocking the drains. This hinders the flow of water during rainfall and contributes to floods.

ii. Global Climate Change have led to change in weather pattern which is sometimes causing unusually heavy rainfall thus causing floods in urban areas.

• For e.g. On 5th Sep 2022, Bengaluru received 131.3 mm of rainfall.

iii. Social and Political apathy

• Religious practices such as dumping of religious symbols, dead bodies etc. in rivers also lead to blocking of rivers. Inefficient management of gathering like Kumbha contribute to unnecessary concretization and thus floods.
• Socio-economic factors contribute to illegal encroachment of flood plains by slums etc. which increases the intensity of the urban floods.
• At the same time we have seen an absence of political will to give priority to the issue.
• This has happened both at national and international level.
• This lack of political will has resulted into paucity of funds which delays the key drainage infrastructure
  • The river water information sharing has remained a major issue between India-Bangladesh and India China.

Consequences

• Human and Infra Loss – deaths and devastation; loss of telecommunication, road and railway lines; increased probability of disease epidemic
• Economic Losses:
  • Other than economic losses because of destruction of infrastructure, floods result in traffic jams, temporary closure of business, destruction of property etc. which leads to loss of manhours, hindering of economic activities etc.
• Environmental Pollution
  • Urban floods also lead to washing away of various pollutants including industrial waste into water bodies thus intensifying river pollution.

Way forward

• Promote the ideas of Sponge Cities -> Urban planning should keep in mind the geological and hydrological cycle: Planned Development of cities should ensure that flood plains are not encroached upon, sinks like ponds are protected/restored and pavements are porous to allow infiltration of rainwater in the ground.
  • There should be increased focus on these goals through an Mission on Sponge Cities.
• Improvement of drainage system.
  • Proper maintenance, desilting of existing drainage system
  • Providing alternative drainage path for flood waters (may be underground)
  • Control of solid waste entering the drainage systems through proper Solid Waste Management
• Change in social attitude of Common Citizen will go a long way in controlling urban floods
  • Reduction of solid waste, promoting environment friendly religious practices can all contribute towards limiting urban floods.
• Disaster preparedness
  • Even after all proper steps, nature may cause havoc and cause floods, therefore a proper disaster management plan should be prepared by the ULBs to be battle ready in emergency situations. Fresh Hazard profiles should be created for the cities based on the historic as well as recent flood vulnerabilities.

Conclusion

• We must not allow nature, human conduct, and urbanisation to be mystified and rendered as trans-historic villains. We can learn to live with nature, we can regulate human conduct through the state, and we can strategically design where we build. We need to urgently rebuild our cities such that they have the sponginess to absorb and release water without causing so much misery and so much damage to the most vulnerable of our citizens, as we have seen in case of Mumbai, Chennai and Bengaluru. 

Practice Questions

• The frequency of urban floods due to high intensity rainfall is increasing over the years. Discuss the reason for urban floods, highlight the mechanisms for preparedness to reduce the risk during such events. [12.5 marks, 200 words] [CSE Mains 2016, GS3]
• Major cities in India are becoming vulnerable to flood conditions. Discuss [12.5 marks, 200 words] [CSE Mains 2016, GS1]
• Account for the huge flooding of million cities in India including the smart ones like Hyderabad and Pune. Suggest lasting remedial measures [CSE Main 2020, GS1]
• Urban floods are a result of ecological disturbance and socio-political apathy. Discuss [15 marks, 250 words]