While the city has registered a rise in the water table, most of the borewells are ‘defunct’. Many have high levels of Salinity, Fluoride, Nitrate, Arsenic, Uranium, and the presence of heavy metals.
Water table rises
The temperature is increasing day by day, and so is the water demand. According to reports, there are 8,891 borewells in the city, 728 of which are not in working condition.
A Bangalore Water Supply and Sewerage Board (BWSSB) engineer said, “2,486 borewells are being handed over by the Bruhat Bengaluru Mahanagara Palike (BBMP), and overall, we will be managing 10,180 in the city. During summer, we take up regular maintenance work to ensure that borewells are fit for drawing water. In case of any reduction in the water table, we will take measures to increase the depth.” Quoted Bangalore Mirror.
Thanks to heavy rains last year, constant growth has been registered in Bengaluru’s water table. The Central Ground Water Board (CGWB) states that 18 wells were analyzed. Out of them, 61.1 percent saw a rise in the water table by 0-2 m, 11 percent saw a 2-4 m rise, and around 16.7 percent saw a fall of 0-2 m. Overall, 83.3 percent saw the water table rise.
Experts reveal that the rise was due to excess rainfall in the city over the last few years. Officials said that the CGWB is occasionally monitoring groundwater levels throughout the country.
An official stated that to consider the decline in water levels on a long-term basis, data from urban areas collected by CGWB during November 2022 was compared to the decadal average (2012-2021). Analysis of water level data concerning cities indicated that about 59.8 percent of the wells surveyed have registered a rise in groundwater levels in the city.
“The Central Ground Water Authority (CGWA) has advised Karnataka to take measures to adopt artificial ways to restore groundwater, and harvest rainwater. A master plan – Artificial Recharge to Groundwater – 2020 – has been prepared by the CGBW in consultation with states. The plan contains provisions for the construction of about 1.42 crore rainwater harvesting and artificial recharge structures in the country to harness 185 billion cubic meters (BCM) of the monsoon rainfall,” said an official to TOI.
The Problem
Groundwater in Bengaluru has higher levels of salinity, fluoride, nitrate, arsenic, uranium, and the presence of heavy metals. 29 districts of Karnataka have reportedly been affected by high, 30 districts have been partially affected due to fluoride, 29 districts by increased nitrate content, three districts due to arsenic, and 22 districts due to iron.
“Karnataka has been advised to install community water purification plants, especially in arsenic and fluoride-affected habitats to provide potable water to every household. This can be done at the rate of eight to 10 liters per capita per day to meet their drinking and cooking requirements. In addition, the quality of groundwater can be improved to some extent if concerted efforts are made,” said Union Minister of State for Jal Shakti, Bishweswar Tudu.
