Bedload Transport in Steep Mountain Streams: Integrating Field Measurements with Flume Experiments

Bedload transport has high importance within sediment budgets of steep mountain streams. The qualitative and quantitative monitoring of both bedload transport and of the active / mobilised channel pavement and channel banks is difficult and a big challeng e. A better general understanding of the mechanisms and dynamics of bedload transport is essential for the improvement of river engineering management and hazard mitigation projects. Most of the existing methods for bedload monitoring do not fulfill the c riteria of obtaining a reliable empirical relationship between discharge in the channel and bedload transport. Interesting and novel studies have been performed using motion-sensing radio transmitters and impact sensors fixed on the stream bed to obtain h igh resolution temporal data on bedload transport. In addition, the spatial detection of stable channel pavement areas/units and the detection of the vertical extent of the active/mobilised channel pavement during bedload transport events as well as of mo bilised/eroded channel banks by using a new "biofilm classification" is a novel and functioning alternative for the quantitative estimation of bedload transport rates during peak-discharges. Integrated field investigations on bedload transport using a com bination of continuous channel discharge monitoring, different tracer techniques (painted stones, magnetic tracers), impact sensors, pit tags and biofilm analysis have been performed in Nordfjord (Erdalen and Bødalen), western Norway since 2004. The integ ration of extended field investigations on fluvial bedload transport and sediment budgets in Erdalen and Bødalen with advanced field studies at East Creek (Coastal Mountains of British Columbia) and extended flume experiments on bedload dynamics at the De partment of Geography at the University of British Columbia (UBC) in Vancouver, Canada is an innovative approach to study mechanisms, controlling factors and rates of bedload transport in steep mountain streams.