Bengaluru Water Crisis: Return to the Core Is the Only Way Out

Of its large number of lakes, Bengaluru is also known as the "city of lakes".  Today this Silicon City has been witnessing an extreme water crisis. 6900 borewells in the city out of 14000 have dried up.The garden city needs 2600 million liters of water daily (MLD) for drinking domestic use and 500 MLD for industry purposes. Of this, 1470 MLD is being provided by the Cauvery River, 1200 MLD is coming from the underground water sources and 650 MLD is being provided by borewells in the city. Through well-controlled measures like water consciousness alerts among communities and by avoiding the wastage of water 20% of the water gap has been bridged and now the situation is under control. The shortage is reduced from 500 MLD to 100 MLD, informed Dr. Ram Prasath Manohar V., Bangalore Water Supply and Sewerage Board (BWSSB) chairman.

Due to the scarcity of rain for some time now, the groundwater level has gone exceptionally down, recharge channels are not working, diminishing reservoirs and borewells are getting empty. In an interview with  Lokmat Representative Dr. Anubha Jain,  T.Krishanappa, Former Deputy Director General of the Geological Survey of India, Bengaluru said that there are a lot of long-term issues, like unregulated construction, destruction of lakes, unsystematic groundwater recharge and poor water storage, hindrances to the natural underground flow of water, people’s unawareness of using water wisely, and climate change that caused this crisis today. He emphasized that rain is the only solution with rainwater harvesting, building ground-level or surface-level tanks to collect lakhs of rain water, recycling or reuse of greywater, and recharge pits should be made compulsory to manage this crisis. He said that in Cauvery Dam there is a lot of silt sand. Deposits in the catchment area might have minerals, and small pieces of precious and semi precious gems along the sand, hence, the government should plan in a way that if silt and sand get separated then capital can also be earned. After removing the 10 feet silt a lot of water accumulation will be there, he added.

Also Read: Bengaluru Faces Extreme Water Crisis: Dwindling Rainfall, Depleted Groundwater, and Dry Borewells

Dr. Ram Prasath Manohar V. in an exclusive interview with Dr. Anubha Jain said, “In 2016 the population was 89 lakh and now the population is 1 crore 40 lakhs. Today we have 10 Lakh 89 thousand water connections. The increasing population and jump in connections are the key factors that are aggravating the water shortage situation. To face this crisis Dr. Manohar said, “We have a threefold strategy to overcome the shortage of water. One is water conservation by implementing water-efficiency technology. By water pro control system on a large scale, current 40% of the water consumption will be saved. We have given a 10-day timeline for people to adopt this cost-effective intervention where water is used for cleaning, and hand washing other than drinking purposes. Second, replace the treated water with fresh water wherever possible. We have identified three construction areas, commercial establishments, and industrial segments. Through this step, we can save roughly 250 MLD of water with ease. Another long-term strategy is to fill the lakes with treated water and recharge groundwater level through various other means.” Dr. Ram Prasath Manohar V. further said, “If the borewells have turned dry and we are not able to rejuvenate them, they can be converted to Rain Water Harvesting structures.” Further, to maintain around 11000 public borewells the BWSSB is planning to use robotic technology. To avoid borewell over-exploitation the BWSSB has also demonstrated the Artificial Intelligence (AI) and Internet of Things (IoT) based borewell monitoring system at a public borewell recently. The technology allows remote control monitoring of the borewell while enhancing the efficiency in managing it by displaying the amount of water usage at specific intervals. This will help to detect the groundwater level before filling them and also help to take necessary action based on the condition of the borewells. The groundwater table can be sustained by recharging the borewell through percolation pits."

An expert Civil Engineer Anand Ramchandra Managing Partner of Vefour Associates and Director of Lake and Water Body Rejuvenation in Rotary Bengaluru in an interview with Dr. Anubha Jain said, “Apart from using Cauvery as the main source of water, we need to go back to our roots. We used to get water from open wells. There used to be a system of interconnected lakes. The lakes were connected by canals, or kaluve, that allowed excess water to be transferred to the next lake. With rain, as one lake overflowed, water went to the next lake, and so on. Because of urbanization the all-important raja kaluve and poshaka kaluve have become defunct.  We can see the bad impact on lakes and these lakes need to be rejuvenated. In Bengaluru, there are roughly 80 lakes and each lake has the potential to give 6 lakh litres of drinking water to their neighbouring areas.” He said that CM Siddaramaiah has recently instructed to increase the groundwater level by filling important lakes in Bengaluru with treated water. With this approach, the Kote Kere or Sihineeru Kere Lake in Devanahalli near Bengaluru airport is being filled with treated water. He further said that through the Hebbal Nagawara Valley (HN Valley) Project, the sewerage water that comes out from the houses is treated and pumped into the 65 lakes of the HN Valley. 

He said, "Without taking water directly from the Devanahalli Sihineeru Kere Lake, a dead open well was revived that was 100 feet away. Tests showed it could yield around 1.50 Lakh litres of water per day and water quality was within drinking water limits. Subsequently, two shallow aquifer borewells in the periphery of the lake were dug to augment the yield of the open well. A shallow aquifer borewell is a 12” deep borewell that penetrates an aquifer up to the rock and not below it.  A PVC casing pipe with slits is inserted into the borewell and the gap between the soil and the casing pipe is filled with a filter system. This taps into the water that percolates the surrounding area of the lake. When tested each of these borewells was giving 50,000 litres of water per day. In these borewells, the filtration system is set up to treat the well water and avoid any risks before it is integrated into the water supply system. The filter is designed by the Indian Institute of Science (IISc). With this pure drinking water was received that was eventually checked by IISc. This can be replicated across India,” he added. Bengaluru and parts of Karnataka are facing the worst water crisis caused by the failure of monsoons in the state. If rain doesn’t arrive shortly whatever authorities say the situation might get worse.