This dataset provides satellite-derived geospatial products for assessing spatial and seasonal patterns of water-related environmental degradation in the Manouba Governorate, Tunisia. The dataset was generated from Landsat 8 Collection 2 Level-2 Surface Reflectance imagery using Google Earth Engine. It includes complementary spectral indices, water-surface masks, seasonal MNDWI products, a Synthetic Water Degradation Index (SWDI), a five-class water-degradation map, a 5,000-pixel spatial sample, AHP weighting and consistency information, and the complete Google Earth Engine processing script. The workflow uses freely available Earth observation data and can be reproduced and adapted for other observation periods and geographical regions.