Evaluation of Variation In Water Quality Affected From Land Use Changed: A Case Study On Gorgan Rod River, In the South-West of Caspian Sea, Iran.

River surface water quality of the River Garaso: A land use changed in the upper Ziarat Basin, Golestan province, Iran ABSTRACT The water quality of the River Ghara so are described in terms of point and diffuse sources of pollution, for this rural area of the upper Ziarat Basin that have had extensive villa building. So, the aim of this research was to investigate the role of urbanization and land use change on water quality in seven stations consisting of Siahab, Angirabad, Shastkalateh, Yasaqi, Naharkhoran, Abgir and Poleordogah. In this paper, principal component analysis and hierarchical cluster analysis methods have been used in order to investigate the water quality of the Gharaso River and to assess magnitude of anthropogenic and natural effects on the quality of river surface water. Therefore, we considered some parameters including temperature, electrical conductivity, total dissolved solids, bicarbonate, chloride, total and temporary hardness, calcium, potassium, sodium, sodium adsorption ratio, sulfate, pH and magnesium as physicochemical variables. The results indicated that water quality in Siahab and Naharkhoran stations was in the poorest quality among other stations because of anthropogenic effects. The best water quality was in Shast Kalateh station because there were no changes in the land uses. The Gharaso River joins the Caspian Sea creating sediment problems and an increasing threat to human and marine health. If these changes continue, there will be a serious threat to the entire ecosystem’s health. Key words: cluster analysis, principal component analysis, quality water, urbanization