Assessment of Lake Water Quality in Central Serbia—Using Serbian and Canadian Water Quality Indices on the Example of the Garaši Reservoir

The water quality in lakes and reservoirs is crucial for maintaining ecological balance and ensuring public health. This research focuses on the water quality evaluation of Garaši Reservoir in Serbia, a vital source of drinking water for surrounding communities. We systematically analyzed three profiles (A1, B1, and C1) at various depths ranging from 50 cm to 1500 cm between 2021 and 2023. The study employed the Serbian Water Quality Index (SWQI) and the Canadian Water Quality Index (CWQI) to evaluate the water quality. The findings revealed significant spatial and depth-dependent differences. Higher concentrations of Aluminum (Al), Mercury (Hg) and Manganese (Mn), influenced by the inflow from the Velika Bukulja River, resulted in reduced overall water quality and suitability for drinking water. Dissolved Oxygen levels decreased with depth, indicating thermal stratification and nearly anoxic conditions, which are harmful to aquatic life. Some shallow areas exhibited poor water quality for recreational use due to high pH and metal concentrations. The study underscores the necessity of continuous and comprehensive monitoring to identify pollution sources and implement mitigation measures. Such efforts are essential to protect biodiversity and ensure the sustainable management of water resources in lakes and reservoirs.