A more acute and continuous decline in Groundwater in Northwest India

Groundwater is a vital resource for domestic, agricultural, and industrial purposes in many regions. However, the increasing demand and unsustainable extraction practices have raised concerns about the long-term viability and sustainability of groundwater storage (GWS), especially in areas where groundwater is the primary source of meeting various demands. Here, we focus on GWS changes in India’s Northwestern states, including Gujarat, Rajasthan, Punjab, Haryana, Uttara Pradesh, and Delhi over two decades (2002-2023). These states encompass 875,249 km² area within the Indus and Ganges river basins, constitute approximately 59% cultivated land, and sustain 525.52 million people. Leveraging GRACE-based TWS data and GLDAS model data, our analysis reveals significant (P<0.05) declining GWS trends with a slope of −20.88 ± 0.53 mm/year, which is more acute than previously reported estimates. Some trend change points in February 2008 and June 2016 are detected that lead to segmented trends with slopes of −18.97 ± 2.45 mm/year (Jan-2002 to Feb-2008), −9.16 ± 1.96 mm/year (Feb-2008 to Jun-2016), −11.80 ± 2.51 mm/year (Jun-2016 to Dec-2023). Spatially divergent trends are found with high decreasing trends of more than 40 mm/year in Punjab, Haryana, Delhi, and some parts of Rajasthan and Uttara Pradesh. This is primarily due to anthropogenic activities like groundwater extraction for domestic and agricultural purposes. In contrast, Gujrat shows subtle positive trends, less than 10 mm/year, due to improved water management, irrigation practices, artificial recharge efforts, monsoonal rainfall, and efficient water extraction management​. Multi-decadal variability and the recent depletion across these six states may foster discussions on policy actions and enhanced multilateral cooperation for a sustainable future, especially in the face of escalating groundwater extraction and a warming climate. This highlights the critical need for immediate attention to water resource challenges in the Northwestern states of India.

Keywords: Groundwater storage (GWS); GRACE; GLDAS; Anthropogenic activities; Policy interventions.