Mehdi Fazeli - Instructor, Civil Engineering Department, Yasouj University; Engineering, State Key Laboratory of Hydro, science
Hongwei Fang - Professor, Department of Hydraulic Engineering, State Key Laboratory of Hydro-science and Engineering,
Yan Liu - BSc. Student, Department of Hydraulic Engineering, Tsinghua University,

Due to pollution in water resources, a microbial biofilm layer can grow at bed surfaces. Biofilm can affect the normal sediment properties. However, little laboratory researches have been performed about biofilm effect on sediment behavior in water system over long time series. Ouraim in this study was to investigate the erosion-deposition phenomena considering factors suchas sediment concentration, flow velocity and bed surface along the flume length. So a flume including three parts was designed; a narrow part and a wide part to show erosion and depositionrespectively and a transition part to connect these two parts. Experiments for various time periods of biofilm growth were managed to measure the required parameters at the flume. Finally the results for various positions were analyzed. Obviously for longer time series of biofilm growth, less values of erosion were measured.

sediment, biofilm, sediment concentration, erosion, deposition,