Assessment on Bentic of Kselian River in Savadkooh Province

Kselian River as one of the most important water sources of Savadkooh province, has special importance. This study consisted of the diversity and distribution of Macrobenthos on Kselian River. In the mentioned area, a total of four study stations were selected based on environmental impact, Macrobenthos fauna samples were taken by Surber such that were repeated 3 times at each station with seasonal frequency. Samples were fixed with 4% formalin, were separated in a lab, and then identified and counted. In surveys conducted, 12 families from 5 orders of Macrobenthos were identified.  The results show in the spring season had the most abundance (290 n/m2) and in the summer season had the less abundance (150 n/m2) of the specimen. Ephemeroptera had the most abundance (62.3 % of total) and Plecoptera had less abundance (3.4 % of total) between five classes were identified on Kselian River. During this study the average of the Shannon-Wiener diversity index was calculated 1.31, Simpson dominance species was calculated 0.28 and Margalef richness species was calculated 1.91. According to the biological values of Hilsenhoff (HFBI), the water quality status of Kselian River at stations 1 and 2 and 4 were evaluated excellent, at stations 4 was evaluated very well. Overall according to the results, it was determined that aquatic insects constitute the dominant population of the benthic fauna in Kselian River.