Assessment of Spatial – Temporal Variations in Freshwater Pollution by Means of Water Quality Index: A Case Study of Hasanağa Stream Basin (Edirne, Turkey)Cem Tokatlı
In this research, spatial – temporal variations of water quality in the fluvial components of the Hasanağa Stream Basin were evaluated by using the Water Quality Index. Surface water samples were taken from seven stations selected on the basin in the winter seasons of 2019 and 2020. Eleven variables including dissolved oxygen, oxygen saturation, pH, electrical conductivity, total dissolved solids, salinity, turbidity, nitrate, nitrite, phosphate and sulphate were measured in freshwater samples. The Water Quality Index (WQI) and Cluster Analysis (CA) were applied to the detected data in order to determine the differences among the spatial – temporal contamination levels and classify the investigated locations according to their similar water quality characteristics. According to the detected data, the water of the Hasanağa Stream Basin has 1. – 2. Class quality in 2019 and 2. – 3. in 2020, in general. According to the results of WQI, although it was determined that the water quality decreased significantly in 2020, the basin was found to be of "A Grade – Excellent" water quality (<50) in both 2019 and 2020. According to the results of the CA, 3 statistical clusters were formed and they were named as “less polluted zone”, “moderate polluted zone” and “more polluted zone”.