An integrated GIS and Remote sensing Approach to Assess Compound Vulnerabilities in Deltaic Geoheritage to Soil Salinization and Coastal Erosion Dynamics in Saloum Delta Senegal

Abstract Low-gradient deltaic Landscapes are globally function as a vulnerable to synergistic soil and coastal hazards. These deltaic geoheritage, although they host hosts a significant concentration of geosites that exemplify millennia of interactions between human societies and their environment, remains under-protection due to a lack of compound approach to asses risks. This research employs an integrated methodological framework to assess deltaic geoheritage compound vulnerability through a case study in Saloum Delta. This approach combines a Soil Salinization Risk Index (SSRI) adapted to deltaic system derived from multi-criteria analysis and a diachronic analysis of shoreline dynamics using satellite imagery and the Digital Shoreline Analysis System (DSAS) tool. Findings reveal an elevated level of vulnerability, with coastal retreat reaching approximately 1,050 meters between 2000 and 2025.The SSRI classified over 85% of the geosites within the “Very High” risk category, reflecting the convergence of unfavorable natural factors: permeable Quaternary sediments coupled with an almost flat topography that limits drainage, alluvial and hydromorphic soils with low permeability, and a high Aridity Index that promotes evaporation and salt accumulation. These results demonstrated how coastal erosion facilitates saline intrusion, which in turn destabilizes natural protective structure, creating a retroactive degradation cycle. This work provides also a replicable methodology for quantifying the sensivity of deltaic geoheritage to interconnected hazards and a decision-support tool for the conservation and sustainable management of this unique heritage.