| Abstract: | This paper reviews the design and performance of pit‐type bedload traps that use pressure pillow and load cell systems to measure the accumulation of sediment. A low cost load cell bedload sampler design is presented. Using a specially designed cradle, a single load cell may be used to measure the load applied on the bottom of an aluminium box of 0·27 m2. Bedload enters the trap through a 0·2 m wide slot cut into a hinged plate on top of the trap. Low profile fences were fitted to the sides of the slot to prevent lateral ingress of sediment. The load cell system converts the immersed weight of sediment directly into an analogue voltage reading that can be stored on a datalogger. Because the load cell is sealed, pressure correction for the water column height is negated. Temperature correction is shown to be necessary for each load cell. The results of laboratory and field calibrations are presented and design improvements suggested. Field data output is illustrated. Copyright © 2000 John Wiley & Sons, Ltd. |
