GIS-based Ecological Vulnerability Assessment in a Mountainous Region: the Charvak Reservoir, Uzbekistan

Mountain reservoirs in steep terrain face geomorphic, hydrological, and development pressures, yet vulnerability maps can be hard to interpret in terms of drivers. An ecological vulnerability index (EVI) is developed for the Charvak Reservoir basin (Uzbekistan) from three subindices: topographic–geological risk index (TGRI; slope, lithological resistance, soil organic carbon, and distance to active faults), hydrological–ecological risk index (HERI; shoreline proximity and normalized difference water index (NDWI) trend risk, excluding the trend term in a nearshore band to reduce shoreline artifacts), and climatic–anthropogenic risk index (CARI; trends in the normalized difference vegetation index [NDVI], normalized difference built-up index [NDBI], and land surface temperature [LST], plus proximity to infrastructure). May–August Landsat Collection 2 composites (2000–2023) yield trends; indicators are scaled to 0–1 and aggregated using analytic hierarchy process (AHP) weights. Hotspots cluster on reservoir-facing slopes and access valleys; the subindices separate topographic controls from shoreline and corridor pressures. Changes in 2018–2023 show limited class transitions, whereas a 2030 scenario (extrapolated NDVI/NDBI plus shoreline and infrastructure stressors) increases high–very high vulnerability by ~39 km2 (~3.2 percentage points), mainly in shoreline belts and development corridors. The framework supports zoning and planning in reservoir basins.