Use of in Situ Analyses to Assess Salinity Risk in the Interdune Depressions of the Southern Korama Valley (Niger)

Background: Since the mid-1990s, the return of rainfall in the southern strip of the Korama valley, south of Zinder (Niger), has led to a hydrological recovery, followed by a phenomenon still new to the area: the salinization of water in interdune depressions. Methods: Water from 21 interdune depressions was analysed in situ during two field campaigns, at the beginning (January) and at the end (April) of the 2026 dry season; both campaigns are complete for 20 depressions. Electrical conductivity (EC), salinity and pH were measured with a calibrated portable multiparameter tester. Seasonal differences were tested with the Wilcoxon signed-rank test. A salinization risk index (SRI) based on the USSL EC classes was mapped by depression, and the EC of depression water was compared with that of the alluvial aquifer recorded at 23 piezometers (2015–2022).