Syllabus: General Studies Paper 3 (Ecology & Environment)
Analyse the causes of urban floods in India. Give some measures to prevent urban flooding in India.
Over the past several years there is increasing trend of urban flood disasters in India whereby major cities in India have been severely affected. Floods in urban areas are causing more havoc as compared to rural areas. recently Mumbai once again struggled to stay afloat after the first heavy spell of rain bringing back memories of the July 2005 flood. Each massive rainfall event is making it evident that the India needs to be prepared to face such a disaster with preventive measures, and resilience.
What is flood?
Flooding is an accumulation of water in an area either by direct rainfall irresistible to the volume of drainage systems or a spill of huge amount of water from water bodies beyond normal limits.
The floods repeatedly draw our attention to only one fact that our urban sprawls have not paid adequate attention to the natural water bodies that exist in them. A number of cities including Chennai are both water-scarce as well as prone to flooding. For the last two decades, urban water bodies have been a victim of unplanned urbanisation in India, because of which they face several threats.
- Meteorological phenomenon
- Natural phenomenon like storms, Cyclone like Vardah, Phailin making landfalls in coastal areas induce heavy rainfall leading to floods.
- Cloud Burst Situations
- Erratic monsoon, monsoon bursts lead to tremendous amount of rain in short period leading to the situation of floods.
- Cemented paves and roads cause choking of drainage with water accumulating above it.
- Lack of exposed soil create a situation of water nit getting seeped into the ground and accumulating.
- Rivers changing its normal course also lead to floods many times. This cause heavy human loss due to unpreparedness and lack of any planning as it is unexpected. Eg: Kosiin Bihar.
- Global Warming
- High evolution of green house gases, resulting in annual temp rise causing melting of glaciers which tend to increase river water level and causes floods.
- Global climate change is resulting in changedweather patterns and increased episodes of high intensity rainfall events occurring in shorter periods of time. Then the threat of sea-level rise is also looming large, threatening all the coastal cities.
- Deforestation and climate change-
- Forest acts as natural barrier against soil erosion, in their absence soil sediments flows directly in river, shallow river basins and more chances of floods .
- Cutting of treesfor personal, commercial and other purposes, especially to expand cities, not only put pressure on environment but also lead to inability of city to prevent flooding. It leads to soil erosion and more frequent floods.
- Encroachment of water bodies
- Urban areas are getting congested. Increasing Migration to the cities and reduced availability of land lead to more encroachment of water bodies and reduced economical services from water bodies putting stress on urban resources.
- Charkop Lake in Maharashtra is a well known example of encroachment.
- Improper planning
- Drainage congestion caused by badly planned construction of bridges , roads , railway tracts, hampers the flow of water and the result is flood.
- Further no plan of how to tackle flooding situation cause trouble. Though cyclones and floods are routinely visiting India, disaster risk reduction concerns have not been integrated into the plan effectively.
- Illegal mining activities:
- Illegal mining for building material such as sand and quartzite both on the catchment and on the bed of the lake have extremely damaging impact on the water body.
- For example, the Jaisamand Lake in Jodhpur, once the only source of drinking water for the city, has been suffering from illegal mining.
- Increasing Urban population and congestion–
- Too much population also result in generation of too much waste and hence sewage.
- This results in choking(caused by plastic waste) of drainage system and affecting free flow.
- Increase in the urban population without corresponding expansion of civic facilities such as lack of adequate infrastructure for the disposal of waste results in waste clogging the natural channels and storm water drains. Thus lead to flooding. Also,
- Urban heat island effect has resulted in an increase in rainfall over urban areas.
- Lack of coordination
- Among centre and state, among state and civic bodies, and various departments at local level lead to poor planning and implementation of any national or state guidelines to control flood.
- Inability to coordinate lead to administrative inefficiency to deal with the urban flood situation.
- Increasing industrialisation and urbanisation have made these water bodies as a dumping yard for industrial effluents and sewage, disturbing both ecosystem and deteriorating water quality.
- All these activities also disturb the natural flow of rivers and during the
time of heavy monsoon they show some erratic behaviour , change their flow and causes flood.
- Unregulated tourism
- Excessive and unregulated tourism lead to stress on water bodies, thorough increase demand, choking of drainage through waste, plastic etc. Ashtamudi Lake in Kerala’s Kollam city has become polluted because of spillage of oil from motor boats.
- Using water bodies to attract tourists has become a threat to several urban lakes in India. Further no regulation on tourists like closing water bodies during stressful season, banning eatables and plastic near water bodies further aggravate the issue.
- Unplanned release of water from dams
- Unplanned release of water from dams without Pre-warning and caution lead to floods many time.
- E.g. Unplanned release of water from Nepal had caused floods in Northern Bihar.
- Detailed survey of the wetlandsshould be done and then every water body and its catchment should be brought under legal protection.
- There should be proper regulation by local bodies and district administration to check construction and developmental activities on riverbanks and ecologically sensitive areas.
- Inclusion of water bodies and their catchment in the city development ruleswill lead to a better planned development of the city.
- Comprehensive urban planning with proper study of topography, drainage, rainfall, soil lithology with improved flood water disposal system.
- Proper steps must be taken by government to check urbanisation through development and employment generation in rural areas.
- CPCB and SPCB must become more vigilant to check pollution in water bodies in the form of chemicals and effluents.
- Ensuring the information must be available and easily accessibleto citizens.
- Frequent awareness and targeted orientation programmes in a manner and language which is understandable to most vulnerable population of the city.
- Help of dedicated NGOs/experts to build the capacity of residents to tackle the situation.
- Several decades old drainage system in India should be improved as they are unfit to meet the demands of the present population. Urban government should use technology like satellite imagery data through Bhuvan and National Urban Information System (NUIS) to map natural drains.
- Water should be taken as a factor while constructing and making architectures of buildings (water-centric approach).
- The warning mechanism need to be updated so as to minimise property and human damage
- Afforestation and shelter belts should be promoted.
“A stitch in time can save nine”, small measures can save many lives and prevent huge destruction. Though climate change and other effects on environment may be the reason for these floods, they are also aggravated and occur frequently in big cities because of anthropogenic activities. There is a need to integrate all the development activities and urban governance. Various organizations and NGOs need to be coordinate with each other and work together. The menace of Urban flood could well be tackled with proper planning and proactive measures.
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