Catchment and channel components of sediment runoff in river flows (granulometric approach).

A model of the channel and catchment components of sediment runoff has been developed. The model makes it possible to estimate the intensity of redistribution of river and bottom sediment in the riverbed, the size distribution of deposited or migrating particles, the mass of particles in the riverbed and catchment components of sediment load, as well as the contribution of the catchment component. The model is based on the assessment of the transport potential of the watercourse and the dynamics of the curves of the granulometric composition of bottom sediment, and products of soil and channel erosion. This approach is focused on the steady flow movement without additional sources of tributary sediment, intensive abrasion of river banks, and products of anthropogenic load. Calculations based on the model applied to the Narva River showed that the contribution of the catchment component to the sediment flow of this watercourse after intense rain is approximately 98%. The obtained results are well confirmed by the weak dynamics of channel deformations in the studied part of the watercourse. [ABSTRACT FROM AUTHOR]