Assessment of Groundwater Sustainability Indicators in a Drought-Prone Region of India

Groundwater is a vital natural resource that supports human health, economic development, and ecological diversity. With its numerous inherent qualities, it has become immensely important for enhancing human water supply in both urban and rural regions of developed and developing countries. However, increasing population, industrialization, mismanagement, and inadequate governance have resulted in unregulated aquifer exploitation and growing contamination of water resources. Consequently, the sustainability of water resources (both surface water and groundwater) is under serious threat in the 21^st century. It is advocated that only groundwater resources can ensure water security, food and nutrition security, and environmental security. Therefore, there is an urgent need to adopt a holistic approach for managing vital water resources.  The groundwater resources sustainability (GRS) indicators developed by UNESCO are useful scientific tools for evaluating the availability of groundwater. These indicators aid in analyzing the extent of natural processes and the impacts of humans on groundwater systems in space and time. In this study, three GRS indicators were used to assess the condition of groundwater annually in the Yavatmal district of eastern Maharashtra, India, during the 2015-2021 period. This district is comprised of 16 blocks and encompasses an area of 13,528 km². In this district, groundwater plays a vital role in sustaining agriculture. However, there is a threat to the sustainability of groundwater in the changing climate. The indicators used are ‘renewable groundwater resources (RGWR) per capita,’ ‘total groundwater abstraction/groundwater recharge (I_A/R),’ and ‘total groundwater abstraction/exploitable groundwater resources (I_A/E).’ The results of the RGWR indicator were classified into three classes, viz., low (0-3), moderate (3-6), and high (>6). It was found that in 2015, 90.65% of the study area was under the low category of RGWR per capita, 5% under moderate, and 4.32% under high. In contrast, in 2018, 67.18% of the area was under the low category, and 32.82% was under the moderate category. In 2021, 58.45% under low, and 41.55% under moderate category of RGWR per capita. The results, based on indicator I_A/R, revealed that groundwater abstraction exceeds groundwater replenishment (I_A/R>100%) in the four blocks (out of 16 blocks) in the year 2015, five blocks in 2018, and one block in 2021. However, the third indicator (I_A/E) revealed that 15 blocks in the study area have underdeveloped groundwater resources (I_A/E<90%), which suggests potential for future groundwater extraction from these blocks. In only one block, groundwater utilization is in overexploited conditions (I_A/E >100%) during the study period. The findings of this study indicate that groundwater sustainability indicators are practically viable tools for formulating efficient utilization of groundwater resources. It is recommended that more groundwater sustainability indicators should be used when adequate data becomes available in the future in order to find a robust set of groundwater sustainability indicators that can help planners and water managers develop a sustainable groundwater utilization plan at a basin scale.