Spatio-Temporal Analysis and Long-term Trends of Groundwater Levels in the Chittur Block, Kerala, India

Abstract

The accelerated global pressures stemming from population growth and industrial expansion have led to the overexploitation of groundwater resource, particularly in hard rock terrains, resulting in a rapid and concerning decline in water table levels. Consequently, a detailed analysis of spatio-temporal groundwater dynamics is crucial for developing effective and sustainable water management strategies. This study undertook a comprehensive spatio-temporal assessment and trend analysis of groundwater levels in the Chittur block, Palakkad district, Kerala, utilizing data spanning a 29-year period (1994–2022). Data from nine observation wells were subjected to rigorous statistical analysis, including the Mann-Kendall test and Sen’s slope estimator, alongside Geographic Information System techniques for spatial mapping. The results confirmed statistically significant decreasing trends in groundwater levels throughout the block, both seasonally and long-term. The most severe declining trends were concentrated in the northern and southeastern regions, a trend primarily attributed to intensive groundwater withdrawal (overexploitation) coupled with insufficient natural recharge. Spatial interpolation further highlighted a heterogeneous distribution of the resource. Significantly deeper water levels (up to 18 m bgl) were observed in areas of high demand, contrasting sharply with shallower levels (less than 6 m bgl) found in zones potentially benefiting from river influence, such as those adjacent to the Bharatapuzha river system. The study strongly recommends targeted interventions, including the implementation of artificial recharge structures and water harvesting techniques, to effectively mitigate depletion. This research provides a robust scientific foundation that policymakers can leverage to deploy localized interventions in critically affected areas, thereby ensuring water security for both the agricultural and domestic sectors within the Chittur block.