Investigation of Seasonal Variations in Water Quality of Karoon River Using Principal Component and Principal Factor Analyses

Assessment of seasonal changes in Surface Water Quality (SWQ) is one of the most important steps in evaluating variations of the river pollution due to inputs of point and non-point source contaminants. The most famous techniques for seasonal variation assessment are multivariate statistical analyses such as Principal Component Analysis (PCA) and Principal Factor Analysis (PFA). In this study, PCA and PFA techniques were applied to identify the most important SWQ parameters which seasonally contributed to water quality variations in Karoon River. To that end, data for nine physical and chemical parameters collected from five monitoring stations in Karoon River during the years from 1379 to 1382 were used. Results showed that important parameters in contributing to water quality variations for one season may not be important for another season. The important SWQ parameters in the spring season were electrical conductivity (EC) and turbidity (Tur), while important parameters for winter season increased to five, including EC, nitrate, pH, water temperature, and total dissolved solid (TDS). However, the main SWQ parameters in summer were chemical oxygen demand (COD), EC, TDS and for autumn were the five-day biochemical oxygen demand, nitrate, pH, TDS, respectively. The presented method in this study can be a useful tool for authorities to assess water quality variations dealing with a large number of data in a water body.