Evaluating the Impact of Land Use Changes on Water Quality in Lake Qarun, Egypt, Using Remote Sensing and GIS-Based Water Quality Index Modeling

Land use and land cover (LULC) changes exert substantial impacts on freshwater ecosystems, particularly in arid and semi arid regions. This study assessed the effects of land use changes on the water quality of Lake Qarun, Egypt, by integrating remote sensing and GIS based modeling techniques. Multi temporal satellite imagery from 1985 to 2023 was analyzed using supervised classification with the Maximum Likelihood Classifier (MLC) to extract LULC classes and identify spatial patterns and trends in land use transformations. Water quality parameters including electrical conductivity (EC), turbidity, dissolved organic matter (DOM), and selected heavy metals were measured at 18 monitoring sites. The temporal analysis of LULC changes revealed significant spatial and temporal transformations, particularly in agricultural, urban, and water body classes. A Water Quality Index (WQI) was calculated and spatially modeled using GIS interpolation techniques to evaluate lake wide degradation. The results showed that WQI values in Lake Qarun ranged from 84.33 to 305.53, indicating that the lake is unsuitable for aquatic life. Water quality degradation was most pronounced in areas adjacent to intensive agricultural and urbanized zones. Urban expansion contributed higher loads of untreated wastewater, while agricultural runoff introduced excess nutrients and pesticides, both exerting a detrimental impact on the aquatic ecosystem. These findings underscore the urgent need for integrated land use regulation and pollution control measures in the Lake Qarun region to mitigate further environmental degradation.