Evaluation of Golgol river water quality in Ilam province based on the National Sanitation Foundation Water Quality Index (NSFWQI)

Setting up a well arranged control plan and water quality monitoring are the most important methods for reducing water pollution and to enhance their quality. Regarding Golgol river importance as one of the main water resources which supplies Ilam dam reservoir as well as disposing different pollutants in to this river, the qualitative analysis of the Golgol river water is necessary. This study was a practical monitoring in which sampling period was conducted during 6 months from 6 stations. The qualitative parameters including: Dissolved Oxygen (DO), pH, TS, BOD, Turbidity, Temperature, Phosphate, Nitrate and Fecal Coliforms. The data were analyzed with National Sanitation Foundation Water Quality Index (NSFWQI) and the river route was zoning with Geographical Information System (GIS) software. The results showed that based on NSFWQI, water quality of Golgol river were in the good or average conditions at all stations and in different months. The maximum index value measured at station #1 (downstream of Zardaloo-Abad village) in June and the minimum amount measured at station #5 (downstream of Jafar-Abad village) in September were 72.5 and 52.1 respectively. In average, during 6 months of sampling period, station #1 with index value of 70.8 and station #5 with index value of 55.1 had the best and the worst qualitative conditions among the other stations. Regarding to study results, the pollution from station #1 toward the subsequent stations has significantly increased and the river water quality has been reduced. Nevertheless, at the last station, due to the river flow increase and its self purification potential, its pollution reduced and the water quality index reveals a better condition. In general, the NSF water quality index is an appropriate index for classification of Golgol river water quality.