ABSTRACT
Two methods are introduced which allow deriving formulas for gravel transport velocity from tracer measurements. In contrast to the commonly used virtual velocity (an average transport velocity during competence), transport velocity here is directly linked to the discharge of the investigated river. For finding linear formulas, a simple method relating the water volumes above a critical discharge to the measured travel distances was developed and applied. The use of discharge histograms in the second method enabled the establishment of potential, polynomial and exponential formulas as non-linear formula types. Application to measured travel distances of tracers at the Mur River, Austria, served to predict the residence time of supplied gravel within a degraded reach. Based on a 60-year hydrograph long-term average transport rates were determined. Large deviations from the average transport rates during the investigation period highlight the importance of the hydrograph for the transport rates, and support the introduced methodology.
