Chennai Floods

Syllabus: General Studies Paper 1

Context:

Tamil Nadu is suffering the fury of the northeast monsoon with heavy floods forcing a near shutdown in Chennai. 

• At least four people have died in the city after rainwater inundated large parts of the residential areas and commercial hubs. 
• It is due to the low-pressure formation in the Bay of Bengal, which caused the heavy downpour.
• As in 2015, an extreme weather event is blamed for the flooding — more heavy rainfall is predicted. 
• Climate experts have warned that such extreme weather events are likely to be frequent in the coming years. 
• Chennai is built on flat coastal floodplains. 
• Wetlands – including natural and artificial drains such as rivers, streams and canals, and water bodies such as ponds, lakes and backwaters – are the city’s insurance against heavy rains and cyclonic storm surges.

Concerns:

The impact of climate change is worsened due to poor reservoir management. The root cause of the city’s distress during rains lies in mismanagement of its water bodies. The unplanned growth of the city has led to the filling up of lakes and tanks and shrunk wetlands. 

• A parliamentary committee that enquired into the cause of the 2015 floods was categorical in its report that “encroachment of lakes and riverbeds played a major role in causing massive floods in Chennai”. 
  • Local mafia is involved in the “illegal business of usurping water bodies for real estate business”. 
  • A mass rapid transport system has severely restricted the flow in Buckingham Canal, which was designed also as a protective barrier against floods and sea ingress.
  • Over 300 lakes, tanks and canals have disappeared in the past decades and, according to the administration, over 1.5 lakh illegal constructions choke the cityscape. 
• Uncontrolled urbanisation: The city’s built-up area grew nine-fold – from 47sq km in 1980 to 402sq km in 2012 – even while area under wetlands declined from 186sq km to 71sq km during the same period.

Chennai will have to reclaim at least a part of its lost water spaces and preserve whatever is left, including its two rivers which have been reduced to large drains, in order to better withstand the vagaries of climate-change-induced weather events.

Way forward for urbanisation in India:

• Wetland policy: We need to start paying attention to the management of our wetlands by involving local communities. 
  • In most of our lakes, the shallow ends, which often lie beyond the full tank level, have disappeared. These shallow ends are called wetlands. 
  • They are sometimes owned by private individuals, other times existing as ecological commons. 
  • Regardless of ownership, land use on even this small scale needs to be regulated by development control.
• Detailed documentation of wetlands and watersheds: Urban watersheds are micro ecological drainage systems, shaped by contours of terrain.
  • We need to consider natural boundaries such as watersheds instead of governance boundaries like electoral wards for shaping a drainage plan. 
  • The Metropolitan Development Authorities, National Disaster Management Authority, State revenue and irrigation departments along with municipal corporations should be involved in such work together.
• Porous building materials: Our cities are becoming increasingly impervious to water, not just because of increasing built up but also because of hard, non-porous construction material that makes the soil impervious. 
• To improve the city’s capacity to absorb water, bioswales and retention systems, permeable material for roads and pavement, drainage systems can be used. It will allow storm water to trickle into the ground, green roofs and harvesting systems in buildings. 
• Making Sponge cities : They absorb the rain water, which is then naturally filtered by the soil and allowed to reach urban aquifers. 
  • This water can be treated easily and used for city water supply. 
  • This implies building contiguous open green spaces, interconnected waterways, and channels and ponds across neighbourhoods that can naturally detain and filter water. 
  • It implies support for urban ecosystems, bio-diversity and newer cultural and recreational opportunities.
  • These can all be delivered effectively through an urban mission along the lines of the Atal Mission for Rejuvenation and Urban Transformation (AMRUT), National Heritage City Development and Augmentation Yojana (HRIDAY) and Smart Cities Mission. 
  • Investments can only be done in a mission mode organisation with the active participation of civil society organisations at the metropolitan scale. 
• Ban against terrain alteration: Builders, property owners, and public agencies have been flattening terrain and altering drainage routes. This causes irreversible damage.
  • Terrain alteration needs to be strictly regulated and a ban on any further alteration of terrain needs to be introduced. 
• Stop the blame: Acknowledging the role of different actors in the city can create a practical space to begin this work. The constant search for a scapegoat to blame should stop.

We need to urgently rebuild our cities such that they have the sponginess to absorb and release water. Doing so will not just help control recurring floods but also respond to other fault lines, provide for water security, more green spaces, and will make the city resilient and sustainable. 

The Indian Express Link:

https://indianexpress.com/article/opinion/editorials/chennai-floods-weather-rain-7615607/

Question- With respect to frequent flooding in Chennai, describe the link of urban flooding with uncontrolled urbanisation in India.