One-Dimensional Non-equilibrium Sediment Transport

Considering the characteristics of non-uniform sediment, a complete equation system is formed for 1-D non-equilibrium transport of non-uniform suspended load. This equation system is the basis of the mathematical model of reservoir sedimentation and river channel evolution. The main contents are summarized as follows: (1) The longitudinal variation equations of sediment concentration is derived for non-equilibrium transport of non-uniform suspended load under the steady flow condition. As shown in the solution, the sediment concentration at a given section is comprised of three components: the local sediment transport capacity at this section, the residual part of the surplus sediment concentration at the upstream section after decaying along the flow path, and the sediment adjustment due to the longitudinal variation of the carrying-sediment capacity. (2) Equations are developed for the variations of the size distribution for suspended load concentration during the massive scour or massive deposition process. These equations can represent the suspended load size sorting during a deposition process and the bed material size sorting and coarsening during a scour process. (3) The theoretical results are compared to and show good agreement with, the field data collected in the reservoirs, channels, and desilting canals and basins along the Yangtze River and the Yellow River, China. The corresponding mathematical models have been widely applied to the sedimentation engineering for the Yangtze River and the Yellow River and the other hydraulic engineering projects. This study is earlier than the systematic study of carrying- sediment capacity of non-equilibrium transport of non-uniform sediment, but the results are basically the same.