The municipal corporation has said it has no data on the city’s groundwater table level. But this year, it has given permission for 71 borewells.
A groundwater level table data is used to estimate the amount of water in the city’s belly and is critical while giving permission to dig borewells. As the city is facing an acute shortage of water this summer, applications seeking permission to dig borewells have increased manifold.
“Groundwater table data is the most important piece of information as it allows us to know the level of water and the natural holding capacity of water at a particular place between November and May when there is no rainfall. This is most crucial while giving out permissions of borewells,” water expert Madhav Chitale said.
Following a bad monsoon last year, the city is already reeling under a 15 per cent water cut. The large number of pipe bursts has further added to the parched city’s water woes.
Sources said that this year there has been a steep rise in applications seeking permission for borewells as compared to the almost-zero applications last year.
“The Brihanmumbai Municipal Corporation [BMC] does not have data of the city’s groundwater table level since there has never been a geological survey done,” said Additional Municipal Commissioner Anil Diggikar.
Civic officials said there had been a primary survey, but a comprehensive groundwater table study is still awaited to assess the most critical data of available water levels.
The BMC has only restricted the depth of borewells and tubewells to 100 ft based on a study on the city’s underground water level by Central Water and Power Research Station (CWPRS), Pune.
The primary report submitted by CWPRS has revealed that underground water is high on saline content and is, therefore, not fit for drinking. The quality of water in the upper layers of the earth is potable, but its quality deteriorates on going deeper and becomes highly saline, the report says.
This is because a considerable part of Mumbai is reclaimed sea land. The report suggested that deep digging for borewells and tubewells could expose fresh water to saline water, thereby rendering it unfit for use.
(With inputs from Sujit Mahamulkar)