Fréchet Distribution and Transport of Suspended Sediments

For the design projects concerning the sediment control structures, a sedimentgraph is commonly used for the determination of sediment load generated by a drainage basin in response to the occurrence of a rainstorm on its surface. The division of total sediment load as attributed and carried by direct runoff and baseflow, respectively, is of paramount importance in these types of studies. A large sample of sedimentgraphs from different geographical areas of the 48 contiguous States is considered in this investigation. A two-parameter Fréchet Distribution is fitted to each one of the sample sedimentgraphs. The two parameters of the Distribution are related to the dimensionless shape parameter and storage time constant for the same given drainage basin. Both parameters are determined through the analysis of the measured suspended sediment data. The calibrated form of the two-parameter Fréchet Distribution describes the natural sedimentgraph curve well and furnishes accurate estimates of the sediments carried by the direct runoff and the baseflow, respectively.