Effect of salmon farming on river water quality (Case study of Mohammadabad Katoul River) using IRWQISC index

Background and Objective: In recent years, the construction of fish farms on the margins of the Mohammadabad Katoul River has increased significantly. The purpose of this study was to investigate the effects of the effluents of these fields on some of the river water quality factors. Materials and Methods: In this study, five sampling stations of 3 rainbow trout ponds were selected for seasonal water sampling in 1396 seasonally with 3 replications, 12 water quality parameters including dissolved oxygen, fecal coliform, pH, biochemical oxygen demand, chemical oxygen demand, temperature, organic phosphate, nitrate, ammonium, turbidity, total dissolved solids and electrical conductivity. Then, fixed effects of data were analyzed using significant test and water quality was evaluated according to IRWQISC. Results: The results show that the water of Mohammadabad Katoul basin is of medium to relatively good quality. The best water quality in autumn with numerical value of 70.5 and the worst water quality in summer with numerical value of 43.3. The reasons for the relatively poor water quality in summer can be attributed to the high activity of the effluent from the fish ponds, such as reduced river discharge, as well as increased recreational activities in the river, agricultural effluents, rural wastewater discharge, and high livestock density. Area noted. Conclusion: In all seasons, water quality was higher than that of other stations during station 1 sampling prior to fish farming. According to the obtained index, it can be generally concluded that river water quality is suitable due to aquaculture activities.