Groundwater potential and sustainability in the Indian subcontinent

Abstract

Understanding regional groundwater characteristics is an important aspect for sustainability. The Indian subcontinent is one of the critical regions because of the high population and rapid developmental activities where the groundwater potential plays a crucial role in meeting the water demands for agriculture, domestic, and industrial purposes. Here we evaluate the characteristics of the major aquifer systems in the Indian subcontinent and divide these into three distinct types viz. sedimentary aquifers comprising 48%, followed by metamorphic crystalline aquifers 32% and igneous crystalline aquifers at 20%.  In 2023, India extracted 241.34 BCM of groundwater though all these aquifers, representing approximately 59.26% of the nation's annual extractable groundwater resource. Severe over-exploitation of groundwater is observed in sedimentary aquifers of the Indo-Gangetic alluvial system, notably in Haryana, Punjab, Rajasthan, and Delhi, whereas significant over-exploitation in metamorphic crystalline aquifers is reported of Tamil Nadu and Karnataka, particularly in cities such as Bangalore and Chennai.   Nevertheless, most assessment units are categorized as 'safe,' offering ample opportunity for sustainable groundwater development. Our review shows that 87% of India's groundwater is extracted annually primarily for irrigation purposes. We observe substantial disparities in the distribution and extraction of groundwater for irrigation across the country, exacerbated by increasing water shortages linked to rising temperatures. These findings underscore the urgent need for building efficient irrigation systems in mitigating climate-induced threats. Therefore, to align with the UN Sustainable Development Goals (SDG-6,13 and 15) and safeguard India's productive aquifer units, it is essential to implement managed aquifer recharge schemes across the country.