عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Helleh, Shapur and Dalaki Rivers are the most important rivers in Fars and Bushehr provinces of Iran. In this study, water quality data of Helleh, Shapur and Dalaki Rivers includes 15 parameters at 24 stations in a seasonal base during the years 2007-2008 were analyzed by Multivariate Factor Analysis technique. The obtained eigenvalues from analysis of evaluated parameters to the main factors showed that the first five factors explain about 83% of variation between the stations. The most important parameters were found electrical conductivity, total hardness, Strontium, dissolved oxygen saturation percent, water temperature, and nitrate regarding to the first factor with 26.167% of the total variance. The second group was included total Iron, Manganese and turbidity related to the second factor with 16.133% of the total variance. Finally, Cesium and Lithium pertained to the third factor explained 15.276% of the total variance. The results of calculating the composite water quality index and ranking the stations showed that the water quality of the stations Tange Chogan, Sarkhon and Cheshmeh Sasan had the best quality and the stations Shekastian, Banejaberi and Dargahi, which are under the influence of evaporitic formations, salt domes, salt springs, and agricultural activities, had the worst water quality. The results showed that the Factor Analysis technique can properly use for finding the most influential parameters and ranking water quality of monitoring stations.