Laboratory studies of total load and apparent bed load

This paper is an analysis of the results of 59 flume experiments conducted in a 100-foot recirculating flume at the U.S. Department of Agriculture Sedimentation Laboratory. Studies were made of total bed material transport as determined by fractional sampling, static and dynamic dune properties, and head losses encountered by flow over an alluvial bed. Under the conditions of these experiments, total load and bed load appeared to be determined by mean velocity alone when moving dunes were present on the bed. If mean velocity was larger than the value producing minimum bed friction factor, total load then became a function of mean bed shear stress alone. The value of the variable α was related rather well to the type of bed form, mean dune height, and the Darcy-Weisbach friction factor relative to the bed. A limited comparison between bed material and bed load transport rates with those predicted according to various formulas showed the Schoklitsch formula to have the best balance between accuracy and ease of computation.