Analysis of the surface water quality parameters in the Aji-Chai Watershed based on the multivariate statistical techniques

One of the most important dynamic ecosystems is the rivers which awareness of the spatiotemporal water quality changes is necessary. In this research, we studied the spatiotemporal water quality changes using cluster analysis, discriminate analysis and Principal component analysis methods in the Aji-Chai Watershed over the last 30 years (1981 to 2010). Based on the Clustering, we identified the three homogeneities cluster. The stations which were labeled in first cluster showed that they are located in the upstream of Aji-Chi River. In compare with other stations, this stations presented that the good water quality and the lowest changeability. DA methods significantly determined the three functions which described about 73.50, 20.30 and 3.40% of total variances. In other word, in general three functions described the 97.20% of the total variances. Also the DA methods identified the HCO-3, SAR, Na, SO42- and Ca2 were the most important water quality parameters which based on this parameters it's possible to identifying the homogenous clusters. Finally, the results of PCA showed that the first two factors were the most important causes of water quality changes in the Aji-Chai River Watershed. This factors described about 78.75 and 14.71% of the variances.