Biological and ecological studies are the most fundamental topics in scientific research and studies related to the management and preservation of water resources. Physico- chemical parameters and biotic community structure are the most important components of aquatic ecosystem. Simultaneous study of them and eva‎luation of the ecosystem according to the results of both of these studies cause better and comprehensive understanding of changes occurring in aquatic ecosystems. Boshar river is the largest river of Kohkiluyeh and Boyer Ahmad province. The catchment area of this river is about 300 km2 and after receiving several tributaries, it leaves the province. The main propose of this study is assessment of Boshar river quality using qualititative and biological indicies. For this purpose, six stations were chosen and sampling of water and amcroinvertebrates have done seasonally (winter and spring of 2019) in two stages with a time interval of three months. For water sampling we used 1 liter clean water bottles and sampling has done from surface of river water and the samples transferred to IUT lab under standard conditions. Macroinvertebrate sampling has been done using D- net. In the laboratory, physico- chemical parameters of water samples (e.g. dissolved oxygen, NO3, PO4, fecal coliform, BOD5, turbidity, TSS and TDS) were measured. Based on physico- chemical parameters NSFWQI and IRWQISC index were calculated. After identification of macroinvertebrates in family level using identification keys, diversity indices (e. g. Shannon- wiener index, Simpson index, Margalef index, Pielou index and richness index) and biotic indices (BMWP and ASPT) were calculated. The results showed that there was a significant difference in most of the physico- chemical parameters (e.g. temperature, dissolved oxygen, po4, turbidity and BOD5) and also fecal coliform between seasons and sampling stations (p>0.05). NSFWQI showed a significant difference (p <0.05) between stations, but no significant difference was observed between the two sampling seasons. Also ASPT, Shannon- Wiener, Simpson, Margalef and Pielou indicies between the stations (p <0.01 and 0.05) but there wasn’t significant difference between two seasons. Based on the findings of this study we can conclude that water quality in Boshar river is different in different sampling stations. Darshahi and Ab malakh stations had the worst and the best water quality respectively. The observed changes in the studied characteristics between the sampling stations are mostly influenced by human activities and changes in the ecological conditions of the river. But between the sampling seasons most of the physico-chemical characteristics, water quality and biological indicies didn’t have any significant changes in Bashar River.

عيسي ابراهيمي، فاطمه پيكان حيرتي

اميدوار فرهاديان

محمد نعمتي ورنوسفادراني، بيرقدار كشكولي