Temporal and spatial distribution of physicochemical parameters and water quality indices in an oligotrophic dam lake: A case of Maksutlu Dam Lake, Sivas, Türkiye

This study was conducted at three selected stations in Maksutlu Dam Lake (?ark??la, Sivas), covering both the dry season (August 2023) and the rainy season (May 2024). Water samples were collected from the lake and a total of 18 physicochemical parameters were analyzed. The eutrophication index (EI), organic pollution index (OPI) and nutrient pollution index (NPI) values were calculated for both seasons based on the physicochemical parameters of the lake water. Additionally, a Geographic Information System (GIS) was used to show the seasonal variation in index values. Bray?Curtis and Pearson correlation analyses were applied to the physicochemical parameters of the water. As a result, it was found that both the physicochemical parameters and water quality indices of the lake exhibited seasonal variation. Phosphate pollution was detected in the lake and it was found that the lake may be oligotrophic in terms of \mathrm{NO_3} and Mg values. Several suggestions were also made for the sustainable management of the dam lake.