Results are presented for a long-duration sediment transport experiment with a plane bed. High-frequency time series of sediment concentration, sediment velocity and solid discharge per unit width were measured using image analysis of video records. A range of transport intensities from a single experiment has been analysed considering transport at different distances from the sidewalls as an independent variable. First and second order temporal statistics of the spatially-averaged values of the transport parameters are presented, which are in agreement with previous studies. A refined statistical analysis of the sediment concentration dynamics, reflecting bed load process, is also given. The characteristic scales of the sediment concentration dynamics are evaluated and analyzed in conjunction with those of the near-bed and bulk flow fields.