Thirteenth International Water Technology Conference, IWTC 13 2009, Hurghada, Egypt  CONCEPTUAL CONSIDERATIONS CONCERNING WATER QUALITY OF GEZEL-OZAN RIVER IN IRAN E. Abdosalehi, H. Banejad *, and H. Zare Abyaneh ** * Ph. D., Assistant Professor Irrigation Dept., Agriculture Faculty, Bu_Ali Sina University, Hamedan, Iran E-mail: hbanejad@basu.ac.ir ** M. Sc. Irrigation Dept., Agriculture Faculty, Bu_Ali Sina University, Hamedan, Iran E-mail: elham_abdosalehi@yahoo.com ABSTRACT This research surveyed water quality of Ghezel-Ozan River that is one of the important rivers on North-West of Iran, for the evaluation of water corrosivity and sedimentation. A total of 16 samples were taken from various points of the Ghezel- Ozan for testing the specific parameters and calculation Langelier Index (LI), Ryznar (RI) and Puckorius Index (PI). According to equilibrium of chemical between salts exist on water on 2 half of a year, to reduce dangers of undesirable quality componentsof Ghezel-Ozan River water. The average of Langelier saturation Index for water of Ghezel-Ozan River, obtained equals 1.22, Ryznar saturation Index is 5.83 and Puckorius Index obtained is 4.66. Comparison of this index showed tendency on sedimentation that must be remedied in order to prevent the sediment and corrosion pipes in order to reduce costs of replacing pipes. Determination the kind of plantation on regions that has salty water is necessary, in order to prevent reducing crop efficiency in these regions. Therefore, in the present research, pay attention toward researching the quality of water samples of Ghezel-Ozan River and to make a comparison of water quality of this river with methods of plantation for using optimum use of the water of this river in order to increase the efficiency of water for irrigation systems. Keywords: Ghezel-Ozan, Zanjan, Iran, corrosion, sediment, quality water, operation, efficiency, Ryznar, Langelier, Puckorius. INTRODUCTION Generally, the water in nature exists in pure form, and has some dissolved and suspense matter. But impurities in the water do not prevent using this water, as long as it is not harmful and more than allowed limits. Factors that closed the dropper are physically and biologically (Alizadeh and Khiabani, 1996). Corrosion is destruction of a matter such as metals in responses to reaction with environment. This environment can be a liquid media such as water flowing in pipes and solid media such as soil in