How To Save Bengaluru from Floods?
Government must remove encroachments on the lakes, and connect them to each other where possible
In the first week of September, many areas of Bengaluru, Karnataka's capital, known as the Silicon Valley of India, experienced flood-like conditions due to heavy rains. Rainwater entered residential colonies as well as IT companies such as Deloitte, Wipro, Ecospace located on the city's outer ring road.
The water was as heavy as a river, flowing on Bengaluru roads. Students and office goers had to resort to boats and tractors to commute. Electricity and potable water supply also shut down in many parts of the city. Several domestic flights had to be cancelled due to waterlogging in the parking area of the airport.
In the last three and a half decades, this is the third incident of heavy rain for 24 hours in the month of September in Bengaluru. First was 177.6 mm of rainfall on 12 September 1988, then 132.6 mm on 26 September 2014 and now 131.6 mm on 5 September 2022.
Bengaluru residents vented their anger on the administration, for the flooding in the city known as the stronghold of IT companies. The city's chief commissioner defended the administration, saying that this year's monsoon has brought more than average rainfall. According to the officials, the first week of September usually records only 25 mm of rain, but this time some parts of the city received 150 to 300 mm of rain in a single day. The Chief Minister of Karnataka said that the flood in the city was due to its overflowing lakes.
Bengaluru is not the only city that has experienced floods after heavy rains, such floods occur in almost all cities of India. Every time it rains, big cities like Mumbai and Delhi are left in ruins.
There are many reasons for floods in Bengaluru. These include unplanned and unregulated development of the city, increase in built up areas, encroachment on the lake areas, silt deposits in the lakes, construction on drains connecting the lakes to each other, declining area under trees.
Bengaluru began to expand rapidly due to the arrival of IT companies. According to a 2016 report by the Indian Institute of Science, the built-up area of the city increased by 1005 per cent from 1973 to 2016. In 1973, only eight percent of the city's area was under buildings. This increased to 27.3 percent in 1992, and 77 percent in 2016, and to 93.3 per cent in 2020. Now, in 2022, the urban area under the buildings would have increased even more .
Land Use Patterns Of Bengaluru 1973-2020
The urban population of Bengaluru increased to 1 crore 27 lakh in 2021, which was only 16,77,000 in 1971. In the last five decades, the population of Bengaluru has increased by 661.49 percent.
The rapid growth of population and the influx of IT companies rapidly reduced Bengaluru's vegetation and watershed areas. According to the above report of the Indian Institute of Science, with urban development and increasing area under buildings, the land use pattern of Bengaluru has also changed a lot. Compared to 1973, the area under vegetation had decreased by 88 percent and the area under water resources had decreased by 79 percent in 2016.
In the historical background, Bengaluru was also called the city of lakes and gardens. These lakes used to fulfil all the water requirements of the people of Bengaluru. Bengaluru is situated on ridges and the monsoon winds bring rain here twice a year (in June-July on arrival and last week of August on departure).
Rainwater accumulates in the low-lying areas. The lakes were connected to each other through canals/minors in ancient times. When some lakes are filled with water due to rain, the excess water is released into other lakes /tanks connecting canals/minors and later people use it according to their requirements.
India has a rich heritage of rainwater harvesting. In every region of the country, rain water was harvested in different ways according to the geographical situation of that region. The southern part of the country is a plateau, here, ponds were built in which rainwater was automatically collected. People used that water for their daily requirements and kept these places clean and also worshipped them.
Under the influence of modernisation, we have started neglecting natural resources. Due to the increase in population in Bengaluru, the area of some lakes has been encroached for constructing buildings, reducing the area of the lakes. The canals/minors which were made to connect the lakes were also encroached in various ways, because they were used only when the lakes overflowed during heavy rains and remained empty for the rest of the time.
Lakes, tanks, and wetlands absorb rainwater like a sponge. This on one hand prevents floods and on the other recharges the groundwater that fulfils daily requirements of the people.
Bengaluru is not the only city to suffer from flooding due to constructions, encroachments and neglect of water bodies. Many other cities of the country like Srinagar, Chennai, Delhi, Mumbai, and some others have also been hit by floods.
In 2014, the flood in Srinagar caused huge destruction. There too, the main cause of flooding was the construction and encroachment of lakes, drains, and the Jhelum river floodplain. According to a research study by Hamaun and Rashid, 50 percent of Srinagar's water bodies have disappeared in the last century due to constructions and encroachments.
The area of Srinagar's largest lake, Wular, declined by 88 percent and the area of Dal lake declined by 50 per cent in 2011 compared to 1901. A similar phenomenon has also happened in Chennai, Tamil Nadu. According to a research study by Anna University, Chennai, at the beginning of the 20th century, had 60 large lakes and tanks, and two rivers named Adyar and Kamu which met the water requirements of the people.
Now the number of these lakes/tanks has reduced to only 26. An airport has been built on the catchment area of Adyar river. Due to the encroachments and buildings built on the water bodies, the city of Chennai was hit by floods in 2015 and in 2019, the city was caught in a severe water crisis.
Lakes, tanks, and wetlands protect us from floods and droughts. According to a 2018 report by NITI Aayog, Bengaluru, which is presently suffering from floods, was also among the 21 cities whose residents will depend on extra-urban sources for drinking water in the near future due to the neglect of natural water sources.
The Karnataka government has also indiscriminately cut down trees from the areas around lakes and tanks in the city of Bengaluru while moving towards the upper ladder of economic growth. By 2016, 88 per cent of the vegetation cover of the city known as lakes and gardens had been lost.
In the last six years, its percentage area would have decreased further. Every region and country should have at least 33 percent of its area under forests/trees to maintain the natural balance. On the one hand, trees help in controlling the rise in temperature and on the other hand, the roots of trees also protect against floods by absorbing excess rain water. In order to protect a place/region from natural calamities like floods and droughts, its natural balance should be taken care of.
Setting Lakes Ablaze
Untreated water from factories and sewage is directly discharged into many lakes in Bengaluru, which sometimes causes fires in these lakes. It is also the responsibility of the city administration that any untreated wastewater is not dumped into lakes, tanks, and other water bodies.
For the treatment of sewage water, the municipal corporation of the city should take appropriate action against the owners of the factories for disposal of the waste water. To save the city from flooding, the places where excess rain water accumulates should also be marked.
By finding a safe place near those places and making deep wells, the rain water should be drained into the earth there, which will be very helpful in solving the problem of both floods and droughts. The area under trees should be increased to control the rise in temperature, and natural calamities like floods in the city. While selecting the varieties of trees, special care should be taken and selecting only local/native trees for plantation so that they can be in harmony with the natural environment.
It cannot be denied that due to climatic changes, the number of occurrences of natural disasters and the intensity of the damage have also increased significantly. Natural resources have to be conserved to avoid these natural calamities.
To save Bengaluru from floods and droughts, the city administration and the state government should remove encroachments on the remaining lakes of the city. The lakes which are possible to be connected to each other, should be connected by constructing well planned drainage. This will ensure that when there is heavy rain, then the city dwellers do not have to face a flood like situation.
Silt deposits and other materials in lakes should be removed and cleaned thoroughly. The city administration should also ensure cleanliness of all types of water sources in the city. If we plan and act soon, we can save Bangalore from floods.
Dr Gurinder Kaur is former professor, Department of Geography, Punjabi University, Patiala