Sediment Transportation Mechanics: Density Currents

This report of the Task Committee on Preparation of Sedimentation Manual, part of their proposed Report on Sedimentation Engineering, deals with the density currents, defined as the movement under gravity of a stream of fluid under, through, or over another fluid, the density of which differs by a small amount from that of the primary current. The basic principles presented are mainly those concerned with the mechanics and sedimentation characteristics of sediment-laden under-flows as found in reservoirs. Means of determining certain basic relationships among the major variables such as velocity, depth, slope, density difference, and the boundary conditions of the underflow are presented. Resistance laws for uniform underflows are examined. The stability and mixing in stratified flows as well as the transportation of sediment by density currents are considered.