Bengaluru may have to be evacuated in a decade if water crisis persists
When a residential complex near Bellandur Junction recently drilled a borewell, they found water at a depth of 1,050 ft. "This is the sixth borewell we got drilled in 10 years. And we are not sure how long water would last in this one," said Ajith Kaverappa, a resident of the complex that has 60 apartments.
Most of the apartment complexes that have come up recently in Bengaluru, especially on Sarjapur Road, Bellandur, Bannerghatta Road, Whitefield, Yelahanka and Marathahalli, depend on borewell. But since these wells often go dry up because of high consumption, the residents and management of the complexes have no other option but to drill new borewells or buy water from private suppliers.
Around 450km away, residents of Gadar village in Raichur, a backward district in north Karnataka, are facing a similar situation. Devendrappa, a 73-year-old farmer, got water at 30 feet below the ground when he first drilled a borewell in his field in the late 1980s. Recently, he had to dig to till 1,020 feet. He used to grow groundnut on 9 acres five years ago, but that has come down to 5 acres. "In another five years, I may not grow anything at all," says a dejected Devendrappa. This is the story across Karnataka. Groundwater, a major resource in times of crisis, is dwindling. Increase n the number of borewells and the decline of groundwater levels have resulted in borewells sinking to the depths of 1,000 feet in several areas.
"The average annual rainfall in Karnataka is 1,248 mm. But the estimated 20 lakh borewells in the state draw almost three-and-a-half times of he amount (rainfall) received to recharge the groundwater. Hence, it's no surprise that most borewells have gone deeper, even up to 1,000 feet, and the ones which aren't as deep have run dry," said a senior hydrologist with the state government.
"Water tables in urban areas are depleting due to increasing population and expansion of piped drinking water. And it is declining in rural areas because of the reduction in recharge areas as a result of lakes and ponds dying," he added.
A study conducted by V Balasubramanian, former additional chief secretary of Karnataka, has sounded a warning bell for Bengaluru: If the current rate of groundwater utilisation continues, there will be a major crisis by 2025 when people may have to be evacuated.
The situation in Bengaluru's immediate neighbourhood, including Bengaluru rural, Chikkaballapur, Tumakuru, Ramanagaram and Kolar, is scarier. Though the government had proposed a Rs 10,000-crore Yettinahole project to quench the thirst of people in these districts, the project got grounded due to protests and technical reasons. "Overexploitation of groundwater for decades and lack of remedial measures have been impacting the level of groundwater in these districts. If the Yettinahole project fails to see the light of day, people may be forced to migrate from these areas in 10 years," some water experts say.
The state is also facing an increase in pollution of groundwater in many areas. The groundwater in about 12 of the 30 districts in Karnataka is highly polluted, a recent study by the department of mines and geology shows. "Groundwater is highly polluted with excess concentration of fluoride, arsenic, iron, nitrate and salinity due to both anthropogenic and geogenic factors, particularly in the districts of north Karnataka. The quality of water is deteriorating due to the mixing of sewerage through unlined open drains, leakage from cesspits and septic tanks, and contamination from industrial wastes," the report said.
Water pollution caused by industries has significant impacted environmental resources. Karnataka, which is one of the top five industrialized states, generates about 6 lakh kilolitres of effluent and liquid wastes every day.
However, the Karnataka government has taken its sweet time waking up to the problem. In 2011, it brought in legislation to restrict digging of borewells and to make rooftop rain water harvesting systems in new constructions mandatory. But, it has had little impact as the laws were not properly implemented and the violations were ignored for various reasons.
Realising that the number of borewells in the state has increased beyond redemption, the government has now put in a regulatory mechanism, wherein only the deputy commissioners have the power to sanction drilling of borewells. But water experts say awareness is the need of the hour than just laws.
"Water conservation should be made a habit. Misuse, indiscriminate use, inefficient use and overuse of water, which we think is freely available, should be contained through rules. However, the government should make serious efforts to promote rainwater harvesting not just among urban residents but also farmers who should be encouraged to dig farm ponds to save water in the agriculture field. The government should also take steps to restore lakes, tanks and canals through NREGS," said Mahendra S Kumar, a former hydrologist.
RAIN BRINGS RELIEF
The groundwater level has gone up in Kolar and Chikkaballapur for the first time in 15 years, thanks to the unexpected rainfall in September and November. Officials say the water level in these drought-prone districts increased by over a metre compared to last year. The groundwater level across Kolar and Chikkaballapur has gone up by an average 1,000 to 1,200ft. Even in Bengaluru city, the level has gone up by more than half a metre. The levels were low till August in many parts of the city, but in November and December, when the city received intermittent showers, the groundwater level rose steadily.