Mining–climate interactions reshape soil–water storage in a coastal sandy basin (Taolagnaro, SE Madagascar), BACI design 1993–2022

This preprint presents an integrated analysis of soil–water storage dynamics (ΔSW) in a sandy coastal basin of southeastern Madagascar (Taolagnaro) affected by large-scale mineral-sand extraction and climate variability. The study combines field measurements of hydraulic conductivity, long-term meteorological trends (1941–2023), remote-sensing indicators, and SWAT+ water-balance diagnostics within a before–after/control–impact (BACI) framework. Results reveal a 66 % reduction in saturated hydraulic conductivity and a shift from near-equilibrium to persistent drying after 2008 (−1.49 mm yr⁻¹). The mining-specific ΔSW deficit (~−0.5 mm ha⁻¹ yr⁻¹) remains robust across sensitivity analyses.Findings highlight reduced infiltration and increased evaporative demand as key drivers of soil-water depletion, with implications for restoration and adaptive management in sandy coastal catchments. This is an independent author version released under CC BY 4.0.