Groundwater under the lens: a remote sensing exploration of storage patterns and trends in Bangladesh

ABSTRACT The increasing demands of agriculture, climate change, urbanization, and industrialization are driving global groundwater (GW) depletion. Bangladesh is particularly vulnerable due to excessive extraction and climatic variability. Real-time groundwater storage (GWS) monitoring is challenging, especially in data-scarce regions, but satellite remote sensing and postprocessing techniques offer valuable alternatives. This study aims to evaluate long-term trends and identify spatial patterns in Bangladesh's GWS using NASA's Global Land Data Assimilation System (GLDAS 2.2) data from 2004 to 2023. It employs kriging for spatial interpolation, the modified Mann–Kendall test for trend analysis, and K-means clustering to detect spatial zones. Results show four distinct GWS zones across Bangladesh. The southeast exhibits the highest GWS (1,514.90 mm), while the northwest has the lowest (783.49 mm). The modified Mann–Kendall test confirms a consistent decline in GWS in all regions: northwest (−2.84 mm/year), southwest (−4.18 mm/year), northeast (−3.65 mm/year), southeast (−3.12 mm/year), and center (−3.94 mm/year). These findings underscore the urgency of implementing region-specific groundwater management strategies. Without targeted intervention, continued depletion may severely impact water security, agricultural sustainability, and long-term ecological balance in Bangladesh.