Effective transport width—A methodology to describe the spatial variability of bedload transport

Abstract

The monitoring of bedload transport processes in rivers is a still challenging task in research and the parameter effective transport width (ETW) allows, for the first time, a process description of the local variability of the bedload transport. In this paper, the distribution of bedload transport over a river cross-section was studied by statistically analyzing long-term monitoring data. Using an innovative integrated measurement system, combining geophones distributed over the river width with bedload traps and basket sampling, allows for continuous, high-resolution, long-term monitoring data of bedload transport characteristics to be generated. Geophone data can be used to record and describe bedload transport processes such as intensity, temporal variability, and local variability. One parameter observed was the ETW, which describes the width where bedload transport is taking place for different discharge classes in gravel bed rivers. With the help of a data series recorded over more than a decade, it is now possible, for the first time, to statistically describe the continuously and directly measured ETW. Hence, it became evident that the effective bedload transport width depends on the discharge rate and local transport capacity, and that bedload transport over the entire river width only occurs at high flows that prevail a few days a year.