Steady declining trend of groundwater table and severe water crisis in unconfined hard rock aquifers in extended part of Chota Nagpur Plateau, India

Abstract

Scarcity of groundwater is a severe problem in this region due to over exploitation of groundwater from unconfined hard rock aquifers. The main objectives of this study are to analyse the spatiotemporal variability and fluctuation of groundwater table and to predict the location of groundwater depression pockets. Total 21 consecutive years (1996–2017) groundwater monitoring well data (pre- and post-monsoon) have been collected from CGWB, Government of India. The nonparametric Mann–Kendall trend analysis and standardized precipitation index (SPI) have been applied to detect the trend of groundwater level and rainfall variability, respectively. Exponential smoothing has also been fitted for future prediction. The pre- and post-monsoon results (1996–2017) showed that around 77% (22 stations) and 78% (23) monitoring stations were indicating declining trend of groundwater table at the rate of −0.006 to −0.205 m/year and −0.005 to −0.192 m/year, respectively. Similarly, future (2040) groundwater depression result predicted that around 75% (21) stations, the groundwater table will be depleted above 5 m during pre-monsoon while about 53% (16 stations) monitoring wells, the groundwater table will be fallen above 5 m during post-monsoon. Consequently, around 52% (15) and 50% (14) stations are being faced groundwater drought in the recurrent interval of above 2 years during pre-monsoon and post-monsoon, respectively. Driving factors of water table depletion are huge withdrawal of groundwater for dry farming and reduction of recharge areas due to rapid land use modification. The uniqueness of this study exhibits the nature of declining trend of groundwater table and identification of depression pockets.

Carving Drought Impact Over Purulia District, West Bengal, India

“…Monsoon precipitation surges G.W. (Groundwater) level in an average depth of 1 -4 m and in Summer depletes by 8 -10 m, wells about 85% dry and vulnerable to the risk of extreme droughts [19,20,21,6]. Mishra et al 2012 [22], from 1908-2009, reveal 28 meteorological droughts, the highest frequency in June.…”

“…table of the Purulia block and confronting G.W. drought [20]. Drought at irregular intervals has shattered the economic and societal life of people of the western part of Bengal.…”

Shortfalls and Challenges in Groundwater Regime Monitoring

“…Higher declining trends will potentially be observed in parts of north-central and south India in the forecasting period of 5 years (2019-2023). Biswajit et al used point data and statistical tools to predict water levels [30]. For 21 consecutive years (1996-2017), groundwater monitoring well data (pre-and post-monsoon) has been collected from CGWB.…”

Assessment of Urbanization Impacts on Coastal Aquifer Vulnerability by Seawater Intrusion Using GIS-Based Modified GALDIT-B Model: A Case Study of South Chennai Coastal Region, Tamil Nadu, India.

“…In addition, urbanisation and land-use change are leading to an unprecedented amount of stress on fresh groundwater resources in many coastal regions (Alphan 2003; Kumar et al 2019;Meyer and Turner 1992). According to research, the dynamic fresh groundwater sources are affected by various factors such as increased domestic and commercial demand, climatic changes, dumping of generated domestic waste and e-waste in land lls (Marimuthu and Ramasamy 2023), nitrate leaching from the septic tanks, swear sumps, and injecting industrial wastage into the underground (Bera et al 2022; S. S. Hasan et al 2020). Further, Demographic changes also tend to create an opportunity for the accumulation and concentration of pollutants within a speci c location (Christensen et al 1994;Liu et al 2019;Radelyuk et al 2021).…”