Surface-based bedload transport relation for gravel rivers

TLDR

Bedload transport in gravel‑bed rivers occurs by mobilizing grains exposed on the bed surface, driven by fluid forces, and the transport rate of mixtures depends on the availability of each size range in the surface layer. The study seeks to develop a surface‑based bedload transport relation for gravel mixtures. The authors transform a substrate‑based bedload relation, derived from field data, into a surface‑based relation.

Abstract

Bedload transport in gravel-bed rivers is accomplished by means of the mobilization of grains exposed on the bed surface. This mobilization is due to the action of fluid forces on the exposed grains. Substrate particles can participate in the bedload only to the extent that local or global scour results in their exposure on the surface. It follows that a calculation of the bedload transport rate of mixtures should be based on the availability of each size range in the surface layer. Herein an existing empirical substrate-based bedload relation for gravel mixtures, developed solely with reference to field data, is transformed into a surface-based relation.