Spatio-Temporal Dynamics of Groundwater Levels under Climatic Variability in North Eastern Karnataka, India

Abstract

The study assessed temporal and spatial changes in groundwater depth and examined the relationship between groundwater conditions and climatic variables in North Eastern Karnataka (NEK). The study covered six districts, namely Bidar, Kalaburagi, Yadgir, Raichur, Koppal and erstwhile Ballari, from 2015-16 to 2024-25. Groundwater depth data were obtained from Central Ground Water Board observation borewells, while rainfall, relative humidity and temperature data were collected from relevant meteorological sources. Descriptive statistics, compound annual growth rate (CAGR), coefficient of variation, the Mann-Kendall trend test and Sen's slope estimator were employed to assess spatial and temporal variability. Partial correlation analysis was used to examine associations between groundwater depth and climatic variables, while ordinary least squares regression was employed to quantify their influence. The results revealed considerable spatial and temporal variation in groundwater conditions across NEK, with mean groundwater depth ranging from 5.52 m bgl in Yadgir to 14.14 m bgl in Bidar and a regional mean of 8.41 m bgl. Groundwater depth became shallower in Bidar, Raichur, Koppal and Ballari, as indicated by negative growth rates, whereas Kalaburagi and Yadgir showed an increase in groundwater depth, indicating deeper groundwater conditions. Trend analysis also showed significant shallowing of groundwater depth in Bidar, Kalaburagi, Ballari and the NEK region. Higher rainfall and relative humidity were associated with shallower groundwater conditions, whereas higher maximum and minimum temperatures were associated with deeper groundwater conditions. Regression analysis confirmed significant effects of all four climatic variables, which jointly explained 69 per cent of the variation in groundwater depth. The study highlighted the need for location-specific and climate-responsive groundwater management, improved irrigation efficiency, artificial recharge and sustainable groundwater-use practices in NEK.