A water quality index was developed for Lake Aygır in Turkey to help manage its water quality. The researchers measured various parameters in the lake over a year and selected specific ones for calculating the index. For drinking water quality, hardness and alkalinity were found to be the most important factors, while ammonia and dissolved oxygen were crucial for fisheries. The index showed that Lake Aygır is suitable for both drinking and fishing, with scores of 149.41 for drinking water quality and 76.11 for fisheries.