Evaluation of water quality in Düden Stream according to different water quality indices

Düden Stream, located in the Antalya Basin, is one of the important surface water resources. The water quality of Düden Stream was monitored by Erdem (2002) from 4 stations on Düden Stream between January 2001 and February 2002 and by ASAT from 4 stations on Düden Stream between January 2021 and February 2022. Within the scope of this study, firstly, the general water quality status of Düden Stream was determined by using the water quality data obtained from the studies conducted by Erdem (2002) and ASAT. In addition, the water quality of Düden Stream was evaluated using the most widely used water quality index models. In this study, the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), National Sanitation Foundation Water Quality Index (NSF-WQI), British Columbia Water Quality Index (BC-WQI) and Oregon Water Quality Index (O-WQI) models were applied and the index results were compared to determine the most appropriate index model for classifying water quality in Düden Stream. The calculation of the index models was based on the limit values in the Water Pollution Control Regulation (WPCR) and Surface Water Quality Regulation (SWQR). Dissolved Oxygen, pH, Chemical Oxygen Demand, Biochemical Oxygen Demand, Total Phosphorus, Nitrate Nitrogen, Ammonium Nitrogen, Temperature, Fecal coliform, Total Dissolved Matter, Total Solids, Sulphate, Chloride, Iron, Aluminum and Manganese parameters were used in the calculation of WQI models. According to the results obtained from the Water Quality Index models, it was determined that the water quality of Düden Stream is generally poor. It was identified that water quality in the Düden Stream sub-basin is under pressure due to point and diffuse pollution sources. It is concluded that urgent measures should be taken at the points with pollution potential to achieve good water status and monitoring studies should be continued. According to the results obtained from this study, it was concluded that CCME-WQI, one of the index models used, is more suitable for the assessment of water quality in Düden Stream.