Application of geographical information in water quality zonation of Ghodarkhosh River

From the past، the rivers were the agent of engender of municipal، industrial and agricultural centers beside the rivers. By increasing the population، growing the technology، increasing the use of water resources and abnormal occupation، the quality condition of rivers are changed. In this respect، the analysis of the qualitative data and the investigation of local information could help us in affecting the quality of rivers for zonation and management control to the accepted level of standard for various usages. Godarkhosh، one of the country''s border rivers in Iran-Iraq border، is located in Ilam Province، with its basin of about 1202. 68 km2. The research area is Godarkhosh river basin which starts from its entrance to the province to its outlet to Iraq. Required parameters such as monthly Biological Oxygen Demand، Total Phosphate، Nitrate، Focal Coliform، Total Suspended Solids، Dissolved Oxygen، Turbidity، pH، and Temperature were measured in 10 sampling stations of Sheshdar، Tanghamam، Tasfiehkhaneh، MehdiAbad، Banvizeh، Chamab، Gardaneh Ghala، Ghebleh، Pole Felezi، and Pole Shekasteh، from autumn to winter 2010. Several studies have been performed regarding surface water quality mainly investigating the effect of unnatural water pollutants. In this research، the reciprocal effects of natural and unnatural factors on river water quality were investigated. Compilation of laboratory results with quality index information layers within the GIS environment demonstrated that Mehdi Abad sampling station with 47. 33 NSFWQI quality index is in a bad and the rest of the sampling stations with 50 to 70 NSFWQI quality index are in the average situation.