Assessment of erosion models using high-resolution transient field data

Wednesday, 17 December 2014
Alexander R Beer1,2 and Jens M Turowski1,3, (1)WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland, (2)ETH Swiss Federal Institute of Technology Zurich, Zurich, Switzerland, (3)GFZ German Research Centre for Geosciences, Potsdam, Germany
Modelling of fluvial bedrock incision is crucial for stream development. Different approaches have been proposed accounting for a variety of driving effects with the stream power model family being the most widely used. Although these models are mechanistically process-based, they are commonly applied at reach or catchment scales in landscape evolution analysis. In these applications, different models often give similar results with appropriate parameter adjustments. However, field tests are rare and there is still uncertainty of their physical plausibility at the process scale.

We present a temporally and qualitatively high-resolved parallel dataset of discharge, bedload transport and bedrock erosion (in minute resolution) for a flood event in an alpine torrent. Using discharge and bedload data we compare the transient behaviour of several model class predictions to the shape of the observed erosion curve and discuss the occurrence of different sediment effects. The bedload`s tools effect is shown to be the dominant driver of erosion and a simple tools-dependent model shows similarly good performance as high-developed mechanistic models.