Groundwater depletion in northern India: Impacts of the sub‐regional anthropogenic land‐use, socio‐politics and changing climate

Abstract

Understanding the key drivers behind intensive use of groundwater resources and subsequent depletion in northern India is important for future food security of India. Although spatio-temporal changes of groundwater storage (GWS) and its depletion in northern India are mapped using the NASA's GRACE (Gravity Recovery and Climate Experiment) records, the sub-regional diverse socio-political and environmental factors contributing to the variability in groundwater withdrawals and renewals are not well documented. Here, we provide new evidence on changes in GWS at different spatial scales using both observations and satellite-based measurements applying both parametric and non-parametric statistical analyses. The substantial loss of GWS has occurred since the beginning of the 21st century, and the decline in GWS is associated with some record-breaking dry and hot climate events. We present how certain state-based policy decisions, such as supplying free electricity for irrigation, prompted farmers to extract groundwater unsustainably and thus led to widespread GWS deletion, which has been also accelerated by frequent dryness and rising temperatures. In the hotspot of Punjab, Haryana and Delhi of northern India, the extracted groundwater during 1985-2013 is equivalent to a metre-high layer if spread uniformly across its geographical domain. We find that the groundwater storage loss in northern India has increased rapidly from 17 km 3 to 189 km 3 between the pre-2002 and 2002-2013 periods. This loss in northern India is, therefore, an excellent example of rapid surface greening and sub-surface drying-a result of an interplay of socio-political and environmental factors. As groundwater continues to be treated as a common natural resource and no clear definition exists to guide policymaking, this study also illustrates how the administrative district level approach can solve the widespread problem of depletion. K E Y W O R D S climate extremes, food security, groundwater depletion, indo-Gangetic plain aquifer, land-use change, socio-political drivers 1 | INTRODUCTION As many regions around the world have started to experience more severe droughts accompanied by a hotter-than-normal climate (i.e., dry and hot events) (Overpeck, 2013), the ubiquitous pressure on freshwater resources is imminent. Specifically, groundwater storage (GWS) losses in the world's agriculturally-important aquifer systems have captured considerable attention of scientific community and policy makers (Dalin et al., 2017; Famiglietti, 2014; Gleeson et al., 2012). This raises the key scientific question-can groundwater act as a

Projected water table depth changes of the world's major groundwater basins

“…With a high population density however, human water requirements are expected to be significant and even increase with climate change and/or the growth of the population. The projected increase of groundwater storage could therefore be reversed and become a decrease, as is already the case in the Ganges valley in North India and in North China where groundwater is already depleted (Rodell et al, 2009;Siebert et al, 2010;Panda et al, 2021). The projected increase of precipitation with climate change could either lead to a replenishment and further increase of groundwater resources in these regions (albeit less than projected in our simulations) or it could be entirely compensated, and even surpassed, by a growing human strain on groundwater.…”

Groundwater Variability Across India, Under Contrasting Human and Natural Conditions

“…Given the high density of reservoirs in south India (Figure S4 in Supporting Information S1), wet extremes thereafter during 2005–2007 (Kumar et al., 2011) generated substantial focused recharge (Asoka et al., 2018; Tiwari et al., 2011), leading to a fast WTD recovery. Conversely, pumping impacts accelerated by drought (Dangar & Mishra, 2021; Mishra et al., 2016; Panda et al., 2021) outweighed the natural recovery process from rainfall in the northern alluvial aquifer, clearly reflected through monotonic drops. These effects are detected by GRACE; however, GRACE alone cannot distinguish storage changes at different aquifer levels (Girotto et al., 2017).…”

“…Comparing the two is complicated by the different hydrogeological conditions, spatiotemporal patterns of depletion, and human interventions (Figures S2–S4 in Supporting Information S1). Chronologically, north India’s groundwater irrigation began earlier; it started in the mid‐1960s at a large‐scale particularly in the northwestern states of Punjab, Haryana, and Rajasthan through the massive crop intensification program, known as the Green Revolution, which triggered land‐use changes and unsustainable groundwater usage (Joshi et al., 2021; Panda et al., 2021; Rodell et al., 2009; Tiwari et al., 2009; van Dijk et al., 2020). Still, to evaluate our hypothesis, we compared the most vulnerable representative states, Punjab (north) and AP (south).…”

Identifying links between monsoon variability and rice production in India through machine learning

“…Bihar), while also simultaneously implementing measures to improve long-term sustainability of water management in other parts of the region (e.g. NW India) to mitigate future negative impacts on agricultural productivity and climate risk 104 .…”