New Delhi: The Council of Scientific & Industrial Research (CSIR) is mulling over a National Water Mapping Programme aimed at finding groundwater hot spots, mapping the structures, and measuring salinity and other characteristics. CSIR-National Geophysical Research Institute (NGRI) has already carried out pilot surveys using helicopter-borne transient electromagnetic technologies in six regions across India.
With a funding of Rs.25 crore from the ministry of water resources, the regions were mapped by the institute are the Rajasthan desert, Indo-Gangetic Plains in Bihar, the Deccan trap region in Maharashtra, South Indian granites in Tamil Nadu, and the east coast sedimentary zone in Karnataka.
“Each terrain has its own structure and its own geophysical qualities, so it is important to assess groundwater in all these areas. Till now data regarding water bodies and ground water is scattered and as a country we haven’t worked on this holistically,” said N. Purnachandra Rao, chief scientist at NGRI. “The government is very excited, discussions are ongoing at ministerial level,” added Rao.
According to Rao, it is estimated that to be able to map all the aquifers of the country, it will roughly cost Rs.12,000 crore over a span of 10 years. “Once the 10 year mapping is done, then there can be real time tracking of all these groundwater sources and we can prepare 3D map structure to show up to 300 metre beneath the surface,” said Rao.
A metal coil from the helicopter is let down and using the electromagnetic signatures scientists can make out if there is groundwater, how deep it is, how saline it is etc, Rao said.
But there will be challenges, according to Rao who said the institute will need to develop its own instruments most of which are bought from other countries, prepare a database of known groundwater sources and mobilize helicopters.
“We need to develop our own instruments, presently we are mostly buying instruments from other countries. We need to prepare a database of sources, mobilise helicopters, and instruments,” said Rao.
India’s per capita availability of fresh water has declined sharply from 3,000 cubic metres to 1,123 cubic metres over the past 50 years, noted a story published in Mint as part of its series on India’s water crisis .
It further highlighted that as much as 55% of India’s total water supply comes from groundwater resources, and that irrigation, of which over 60% comes from groundwater, takes up over 80% of total water usage in India.
“We have recently got solid proof of concept that the program can be carried out using the proposed technology. Some hot spots have to be shortlisted and discussions are at very early stage with the Ministry,” said Girish Sahni, director general CSIR.