Evaluation of water quality variation of Zarringol river, Golestan province

One of the most important factors in sustainable development of watersheds is suitable water resources availability in terms of quantity and quality. Along with industrial development, population increase and lack of proper environment control, contamination risk threats the water resources. Water quality properties are the very important component of water resources management and a watershed health assessment. In the case study undertaken, based on data available in the Zarringol station located on the Gorgan river of Golestan province in 1998 to 2007 water quality analysis with drawing Piper, Schoeller, Wilcox, Durov, Gips and Stiff, diagrams was performed. For comparing of treatments ANOVA, to test the statistical difference between the years, the LSD, and to determine trends in the test data Kendall test were used. Results showed that the Zarringol water was the saline water type and is approaching to chloride type. Calcium and magnesium ions have an important role in determining the type of river water quality. This river was assessed as moderate to low that had been placed in C3S1 class in Schoeller diagram and suitable for irrigation in lands with good drainage and coarse soil texture. Chemical quality of Zarringol River has been affected by evapotranspiration reactions. The magnesium risk increased and the risk of salinity in the river is too high. Generally it can be said that because of severe manipulation of the natural environment including roads building and mining in the Zarringol river, water quality declined. It can be recommended that water quality monitoring in head waters of Zarringol River will be done in order to show the effects of each branches in water quality at Zarringol River.