URBAN FLOODING IN INDIA

WHY IN NEWS:

• On 14 October 2020, heavy rains resulted in flash flooding in many areas of Hyderabad, causing the deaths of at least 80 people

BACKGROUND:

• Urban floods in India have slowly started to become a regular phenomenon.
• Recent events of urban floods includes Chennai floods of 2015 Mumbai floods of  2017, Guwahati floods of 2010, Bengaluru floods 2017 and Hyderabad floods of 2020
• Gurugram over the past few years comes to a complete standstill during the monsoon months.
• Floods in India are an outcome of both natural and anthropocentric changes. However the latter has been more responsible for floods in the current age of Anthropocene.

NATURAL CAUSES OF URBAN FLOODING:

• Meteorological phenomenon:
  • Cyclone like Amphan, Nisarga making landfalls in coastal areas induce heavy rainfall finally leading to flooding.
• Excessive rainfall:
  • For example heavy rains caused by Deep Depression BOB 02 resulted in flash flooding in Hyderabad in Oct 2020
• Change in course of river:
  • Eg: Kosi river causes flood in cities and towns of northern Bihar

MAN-MADE CAUSES OF URBAN FLOODING:

• Inadequate drainage infrastructure:
  • Cities like Hyderabad, Mumbai rely on a century-old drainage system, covering only a small part of the core city.
  • In the last 20 years, the Indian cities have grown manifold with its original built-up area.
  • As the city grew beyond its original limits, not much was done to address the absence of adequate drainage systems.
• Pollution:
  • 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 flooding.
• Terrain alteration:
  • Lasting irreversible damage has been done to the city by property builders, property owners, and public agencies by flattening terrain and altering natural drainage routes.
• Reducing seepage:
  • Indian cities are becoming increasingly impervious to water, not just because of increasing built up but also because of the nature of materials used (hard, non-porous construction material that makes the soil impervious).
• Unplanned tourism activities:
  • Using water bodies to attract tourists has become a threat to several urban lakes in India. Ashtamudi Lake in Kerala’s Kollam city that has become polluted because of spillage of oil from motor boats
• Lax implementation:
  • Implementation of provisions of rainwater harvesting, sustainable urban drainage systems etc. and adoption of Environment regulatory mechanisms like the Environmental Impact Assessment (EIA) remains weak.
• Encroaching Natural Spaces:
  • Charkop Lake in Maharashtra, Ousteri Lake in Puducherry, Deeporbeel in Guwahati are well known examples of encroachment.
• 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.
• Absence of administrative framework:
  • The government does not have data on the total number of urban water bodies in the country.
  • Few cities have recorded water bodies because of court rulings.
• Cultural or religious festivals also misuse water bodies.

NDMA GUIDELINES ON URBAN FLOOD MANAGEMENT:

• Creation of a National Hydro-meteorological Network:
  • In 2010, NDMA had issued guidelines on Urban Flood Management in India to create a National Hydro-meteorological Network.
  • The guidelines say that for providing early warning, the Central Water Commission (CWC) should maximize the real-time hydro-meteorological network to cover all urban centres to effectively deal with the problem of urban flooding
• Use of technology:
  • Use of Doppler Weather Radars to be expanded to cover all urban areas in the country
• Data collection:
  • An inventory of the existing storm water drainage system to be prepared. The inventory will be both watershed based and ward based
• Flood resilient infrastructure:
  • All future road and rail bridges in cities crossing drains to be designed such that they do not block the flows resulting in backwater effect
  • Every building in an urban area must have rainwater harvesting as an integral component of the building utility.
• Land management:
  • Low-lying areas in cities have to be reserved for parks and other low-impact human activities.
• Delinking of urban flood and rural flood:
  • Urban Flooding has to be dealt as a separate disaster, de-linking it from riverine floods which affect the rural areas.

BEST PRACTICES:

• Local:
  • Integrated Flood Warning System for Mumbai (I-FLOWS Mumbai):
    • It is a monitoring and flood warning system that will be able to relay alerts of possible flood-prone areas in advance.
    • Similar systems are being developed for Chennai, Bengaluru and Kolkata.
• International:
  • China’s sponge city initiative:
    • It sets an ambitious goal - by 2020, 80 percent of urban areas should absorb and re-use at least 70 percent of rainwater.

WAY FORWARD:

• Proper planning framework:
  • Detailed survey of the wetlands and then bring every water body and its catchment under legal protection.
  • Inclusion of water bodies and their catchment in the city development rules.
  • Comprehensive urban planning with proper study of topography, drainage, rainfall, soil lithology with improved flood water disposal system
  • In a changing climate, the drainage infrastructure (especially storm water drainage) has to be built considering the new ‘normals’.
  • Each city should have their flood mitigation plans strongly embedded within the master plan of the city.
• Management of wetlands:
  • We neglect the issues of incremental land use change, particularly of those commons which provide us with necessary ecological support — wetlands.
  • We need to start paying attention to the management of our wetlands by involving local communities.
  • The risk is going to increase year after year with changing rainfall patterns and a problem of urban terrain which is incapable of absorbing, holding and discharging water.
• Proper solid waste management system:
  • Control of solid waste entering the drainage systems
• Need For holistic engagement:
  • Urban floods of huge scale cannot be contained by the municipal authorities alone.
  • Floods cannot be managed without concerted and focused investments of energy and resources.
  • The Metropolitan Development Authorities, National Disaster Management Authority, State revenue and irrigation departments along with municipal corporations should be involved in such work together.
  • Such investments can only be done in a mission mode organisation with active participation of civil society organisations at the metropolitan scale.
• Developing sponge cities:
  • The idea of a sponge city is to make cities more permeable so as to hold and use the water which falls upon it.

PRACTICE QUESTION:

Q. “We need to urgently rebuild our cities such that they have the sponginess to absorb and release water”. Analyse this statements in the light of recent occurrences of floods in Indian cities.