Evaluation of Temporal and Spatial Variations of Water Quality Parameters in Zohreh River, Iran

Discriminant analysis (DA) and principal component analysis (PCA), as multivariate statistical techniques, are used to interpret large complex water quality data and assess their temporal and spatial variation in the basin of the Zohreh river. In this study, data sets of ۱۶ water quality parameters collected from ۱۹۶۶ to ۲۰۱۳) in ۴ stations (۱۵۵۴ observations for each parameter) were analyzed. PCA for data sets of Kheirabad, Poleflour, Chambostan and Dehmolla stations resulted in ۴, ۴, ۴, and ۳ latent factors accounting for ۸۸.۹۸۵%, ۹۳.۸۲۸%, ۸۸.۶۴۸%, and ۸۸.۶۸% of the total variance in water quality parameters, respectively. It is indicated that total dissolved solids (TDS), electrical conductivity (EC), chlorides (Cl−), sodium (Na), sodium absorption ratio (SAR), and %Na were responsible for water quality variations which are mainly related to natural and anthropogenic pollution sources including climate effects, gypsum, and salt crystals in the supratidal of Zohreh river delta, fault zones of Chamshir I and II, drainage of sugarcane fields, and domestic and industrial wastewaters discharge into the river. DA reduced the data set to only seven parameters (discharge, temperature, electrical conductivity, HCO۳-, Cl-, %Na, and T-Hardness), affording more than ۵۸.۵% correct assignations in temporal evaluations and describing responsible parameters for large variations in the quality of the Zohreh river.

Keywords:

Zohreh River , Water quality , Principal component analysis , Discriminant analysis , Iran