Influence the amount of total organic matter (TOM)and Grain sediment on dispersal of Macrobenthic community in Western Haffar river in khoramshahr

128 kilometers in the city of Ahwaz and khoramshahr in southwestern khouzestan is located. Karoon River before reaching the Persian Gulf, in khoramshahr Divided two branches Bahmanshyr and Hafar. In to the importance of Hafar River Hydrology situation that fresh water and salt water are important Macrobenthic it will. In this study selected 10 stations within the study scope. Sampling, March 86 started and ended in September of 87. Samples by Grab Van Vienn (025/0 m2) in both warm and cold season and once in each season was done. To the 3 samples from each station to identify benthic sediment and one sample for Grain sediment Analysis (GSA) and Total organic materials (Tom) were harvested. Physicochemical parameters of the DO, salinity, PH and temperature were analyzed.Macrobenthic between groups identified the most abundant Insect group and sex Nereis sp.Identified Macrobenthic groups consist of Polychaete 65.19%,Gastropoda 29.65%,Bivalvia 4.97% and Insecta 0.18% respectively.In stations that the amount of material dissolved was high,macrobenthics was significantly redused.in station 1(saboonsazi factory)and residual tissues silt_clay and sand was fine to their numbers.most the benthic community in the river downstream stations were observed in the amount of organic matter in sediments of this stations is less.In general, sandy sediment and low organic matter sediment contain more were the most community.