The Brihanmumbai Municipal Corporation (BMC) and the Groundwater Surveys and Development Agency (GSDA) will map the city’s groundwater table next month.
The project, which will be conducted over the next year, will help the civic body gauge the quality and the quantity of the groundwater.
Confirming this, additional municipal commissioner Rajiv Jalota said, “We have commissioned the GSDA to carry out this survey for us. Such a survey was the need of the hour, considering that prior to this we had little idea of our groundwater resources.”
Suresh Khandale, GSDA joint director, said, “The whole idea of the survey and the study succeeding the survey is to gauge the groundwater. Also it will help in marking the city’s areas into three categories depending on the quality of groundwater — sweet, saline or brackish.”
According to Khandale, Mumbai has been using a lot of borewell water. “Hence the groundwater table is depleting and we don’t know whether it has been replenished or not. This survey will aim at marking out areas for such use, as well as areas where such indiscriminate use should be avoided.”
After the poor rainfall in 2009, the BMC had encouraged the use of borewells and ringwells only to realise later that the city's groundwater table was at peril.
Khandale said that the first stage of the survey would include mapping out the wells, ringwells and borewells. An inventory will be prepared based on the quality and quantity of water fetched from these wells.
“The next step would be to take water samples from these spots, which will be checked for contamination and metal content,” he said, adding that they will be monitored for the duration of the project.
The study will also map out ‘hot spots’ for availing groundwater. “These will be spots where digging a borewell will fetch sweet water that can be used for drinking,” said Khandale.
The data collated from these studies will then be mapped through a Geographical Information System (GIS) into a base map of the city.
The GSDA will also make recommendations to the civic body on the steps to be taken to recharge the groundwater table. “We will study the hydrological cycle till October next year so that we know the pattern of groundwater usage, quality and quantity throughout the year,” Khandale said.