Full Measure

THE ROLE OF THE NATIONAL AQUIFER MAPPING AND MANAGEMENT PROGRAMME IS CRITICAL TO REVERSE THE TREND OF DEPLETING GROUNDWATER LEVELS ACROSS INDIA

- Dipankar Saha

INDIA’S AGRICULTURAL production journey—from external dependency to meet foodgrain requirements at the time of Independence to self-sufficiency today—is intricately tied to the groundwater resources of the country. Today, no country in the world is as dependent on groundwater to sustain its water needs as India. The country consumes about a quarter of global groundwater, which is more than the next two countries combined, the USA and China.

Though huge investments have been made over the decades for surface water-based schemes for irrigation and drinking supply, groundwater remains the lifeline of water security. But reckless exploitation of aquifers is gravitating India towards a water disaster. Assessment by the Central Ground Water Board (CGWB) and research-based on grace satellite data amply demonstrated rapid aquifer desaturation at many places.

Of the 6,881 blocks/talukas assessed in the country, 17 percent are overexploited. These overexploited areas have invaded all aquifer typologies—from prolific soft rocks aquifer system in Punjab, Haryana and western Uttar Pradesh, complex heterogeneous aquifer systems in arid areas of Rajasthan and Gujarat to low-potential hard rock aquifers in Karnataka, Tamil Nadu, Telangana, and Maharashtra.

The economic and social consequences of groundwater overexploitation have led to mounting economic burden on farmers owing to relentless construction of deeper new wells, increased energy cost to lift water, enhanced water salinity and spread of geogenic contaminants—arsenic, fluoride, salinity—and ingress of seawater in freshwater aquifers in coastal areas. Further, we are yet to fully comprehend its impact on environment and ecology. The likely effects are diminishing the flow of non-glacier fed rivers, drying up of wetlands, changes in hydraulic behavior of aquifers—particularly in the multi-aquifer setup in the Indo- Ganga-Brahmaputra Plains.