Total Sediment Load from SEMEP Using Depth-Integrated Concentration Measurements

摘要

This study improves total sediment load calculations on the basis of depth-integrated sediment concentration measurements for channels with significant sediment transport in suspension. The series expansion of the modified Einstein procedure (SEMEP) removes most of the empiricism found in the existing modified Einstein procedures (MEP). SEMEP calculations require field measurements of flow discharge, depth-integrated suspended sediment (SS) concentration, and suspended particle sizes. SEMEP calculates the Rouse number, Ro, from the median particle size measured in suspension d_(50ss). On the basis of the sediment discharge measurements collected from 14 rivers, the accuracy of sediment discharge calculations depend on the ratio of the shear velocity u_* to the settling velocity to. SEMEP performs accurately (error less than 25%) and without bias when u_*/ω > 5. Calculations are also acceptable, but less accurate when u_*/ω is between two and five. Both SEMEP and MEP should not be used when the value of u_*/ω < 2, and a simplified formulation on the basis of bed sediment discharge is recommended when u_*/ω < 2.