Continuous monitoring of morphological changes from sediment augmentation by field measurements and flume experiments

In this study, we present results from continuous field monitoring and a flume ex-periment of a sediment augmentation measure in a residual flow reach of the Swiss midlands. A straight morphological channel with fixed bed material was constructed to represent the impact reach of the field experiment. The slope was separated into different linear sections, each repre-senting a different riverbed structure from the field. Sediments were placed in the flume in four deposits, with a geometrical configuration similar to the field experiment, and mobilized by scaled hydrographs of two former flood events. The results were compared to tracked particle movement of the augmented sediments by passive integrated transponder (PIT) tags at the study site. The objectives are to analyze erosion and deposition patterns of in-channel sediment deposits with regard to the influence of existing bed structures, deposit geometrical configuration and flood repetition. In addition, different physical model scaling approaches were tested and shortcomings of the final model representation are discussed. In this study, we highlight the importance and difficulties of representing morphological characteristics, like bed structures, for reach scale sed-iment processes and morphodynamics.