A Novel 2D Transport Model for Bed Load Pulses Caused by Local Sediment Surplus

Bed load pulses are highly complex phenomena which can be observed under a wide range of flow conditions, stream types and sediment supply. Although a large variety of field and laboratory research was conducted in the last decades, many uncertainties remain in characterizing and modeling sediment pulse propagation. The present paper complements existing research by providing a detailed analysis of the two dimensional transport and dispersal behavior of bed load pulses originating from locally installed sediment deposits. Moreover, a novel two dimensional model, based on a two-parameter gamma distribution (GGM), to predict the pulse propagation is introduced. Therefore, laboratory experiments were conducted using a contactless, image-based measurement technique to determine the distribution patterns of the pulse. The results reveal a decreasing trend in the bidirectional sediment advection and dispersion over time, following the shape of a power law decay function. Further, predominance of the advective component was found for both directions. The proposed model is capable in predicting the magnitude, shape and extent of the propagating sediment pulses on a high level of accuracy.