Bengaluru Floods

What is the issue?

In overnight rainfall, areas in Bengaluru were inundated raising again the old questions about the reasons behind the flooding.

How much rain has Bengaluru received in August 2022?

• The India Meteorological Department (IMD) has said that in August 2022, Bengaluru received 370 mm of rainfall, falling only a little short of the all-time record of 387.1 mm of rainfall.
• Since June 2022, the city has received 769 mm of rainfall, departing significantly from the average of 425 mm in this period.
• In the last decade, the August of 2017 and 2011 were very wet whereas other years were dry.

What is the reason for the flood?

Urban flooding refers to the inundation of property in a built environment, particularly in more densely populated areas, caused by rain falling on increased amounts of impervious surfaces and overwhelming the capacity of drainage systems.

• Rainbow Drive Layout Flood- Rainbow Drive Layout Area was created near a drain that was used primarily for irrigation.
• Over a period of time, the buildings which were constructed close to the layout raised their height, thereby making the area a “soup bowl”.
• The excess water from the surrounding villages is being directed to the Rainbow Drive Layout.
• Outer Ring Road Flood- Chief Minister Bommai found that the major reason for the flooding of the area was the encroachment of stormwater drains.
• The width of the drain had come down from 30 feet to 4 feet.
• Lack of infrastructure is one of the biggest reasons why ORR floods every year.
• There are quite a few engineering flaws in the development of the road such as the lack of culverts.
• The flyover on ORR doesn’t have any water harvesting system.

How is the administration addressing the flood?

• Legal procedures are being looked after which the properties encroaching on the drain would be demolished.
• An order was promulgated for the construction of a drain on a public-private model that will carry rainwater from the Layout to the Sarjapur culvert.
• With the change in the topography of the area, a new drain design is being looked into.
• Need of the hour- Standard operating procedures (SOP) listed by Urban development ministry at various stages of preparedness ghas to be followed.
• Development needs to be climate-smart by preventing any further worsening of the hydrological patterns in cities. 
• Existing construction on lake beds and other water bodies needs to be removed or redesigned to allow flood drainage along natural water channels.

References

1. https://indianexpress.com/article/explained/explained-climate/monsoon-bengaluru-floods-rains-weather-8126932/lite/
2. https://www.thenewsminute.com/article/bengaluru-s-outer-ring-road-s-broken-infrastructure-why-it-floods-167493
3. https://www.nrdc.org/experts/anna-weber/what-urban-flooding