Land use change (LUC) is important for natural landscape transformations and global environmental changes. Illegal land use practices such as unauthorized landfills and wastewater discharge sites within the river basin of Chepelarska are investigated in our study by applying field observations, remote sensing, and geographic information systems (GIS). They were analyzed based on the following factors: land use, slope gradient, distance from settlements and roads, hydrogeological characteristics of the substrate, and distance from watercourses. In three case areas in the Chepelarska River Basin, the illegal widespread household and construction waste is the following: solid waste, e.g. packaging waste (biodegradable materials, polyethylene bags, cardboard, glass), tires, bricks, tiles, ceramics, concrete, cement, cables and pipes, ash and slag, bark and wood waste, wood shavings), and wastewater discharge sites. The results emphasize the possibility of easy-to-use devices for recording the locations of illegal waste disposal sites and the importance of geographic information systems (GIS) studies for monitoring the land-use change in the Chepelarska River Basin. The detected new wastewater discharge runoff sites complement the data of the East Aegean River Basin Directorate - Plovdiv.

Our analysis revealed that illegal dumps in and around urban areas and Pamporovo Ski Resort altered land use and influenced how locals and visitors perceived the landscape.