SEASON OF FLOODS GS- 3 DISASTER MANAGEMENT, URBAN FLOODS

CONTEXT

Recently, torrential rains that took place in Chennai have caused massive urban floods. In most parts of India, urban floods have become an every year  phenomenon in recent years.

As the incidence of extreme weather events and  climate variability increases, urban flooding becomes more and more common especially in urban areas. While the heavy downpour can be attributed to changing climate patterns, the urban flooding is largely due to an unplanned haphazard urbanisation.

MAN-MADE DISASTERS

Unregulated construction with no regard to the natural hydro-geomorphology, topography and over burdened drainage systems, all make urban floods a man-made disaster.

  • Poor Urban Drainage: Major urban centres like  Delhi, Hyderabad, Mumbai rely on a century-old drainage system, covering only miniscule part of the core city. With the pace of urbanisation Indian cities have grown manifold with its original built-up area however not much was done to address the absence of adequate drainage systems.

  • Haphazard Construction: Lasting irreversible damage has been done to the city by leveling & flattening landscape and altering natural drainage routes. Unplanning construction of cities compounded by problems of illegal encroachments which eliminate natural watercourses necessary to drain excess water.

  • Concretisation: Indian cities are becoming increasingly impervious to water because of the nature of materials used which are hard, non-porous construction material that makes the soil impervious and which does not allow the water to reach natural aquifers.

  • Weak Institutional & Legal framework: Even with scientific methods of rainwater harvesting, sustainable urban drainage systems, etc, in regulatory mechanisms like the Environmental Impact Assessment (EIA), adoption at user end as well as enforcement agencies remains weak.

  • Destruction of urban environment: The number of wetlands has reduced to 128 in 2018 from 683 in 1956. Forest cover in urban areas is only 9 per cent, which ideally should have been at least 33 per cent. This led to the major changes in the natural patterns of the weather over urban centres.

MITIGATION FOR URBAN FLOODING

  • One of the best solutions to reduce the chances of flooding is to plan construction away from floodplains and high flood hazard zones. The major challenge lies in identifying  such zones and water bodies but using geospatial data.

  • New construction in flood-prone areas must be strictly regulated and in areas where constructions had already finished or rather encroached upon should be monitored regularly. Structural measures of flood control like increasing stormwater drainage capacitors, should be adopted by the urban management on priority basis.

  • Government programmes like the Atal Mission for Rejuvenation and Urban Transformation (AMRUT) and Sponge Cities mission can go a long way in helping urban authorities to plan cities keeping flood risks in mind. Further, commercial, residential and government buildings should mandatorily install green infrastructure options like rain gardens,  green roofs, and rainwater harvesting systems.

WAYFORWARD

Urban Flood management will not just help controlling regular floods but also cater to other fault lines, provide for water security, more green spaces, and will make the city resilient and sustainable.

Download Plutus IAS CURRENT AFFAIRS 13th November 2021