Continuous simulation of sediment transport in the case of a glacierized watershed

Sediment supply in mountain streams is permanently fluctuating. Under natural conditions, the transport is mainly caused by storm flood waves and snow or glacial melting processes. The information about the variation of the transported material at these events and about the change in size distribution and rate is very scarce, since only few direct observation stages exist, e.g. Lauffer-Sommer (1982), Zeller (1985), Tacconi-Billi (1987). At the Pitzbach, a small tributary of the river Inn, a particular device has been prepared in form of a tyrolian weir to continuously monitor bed load and suspended matter. Resulting load graphs permit the evaluation of relations that govern the sediment supply. This paper continues and extends the work presented earlier by Hofer, (1985) and Schöberl, (1988). It can be shown that characteristic features of the discharge hydrograph dominate the bed load discharge, while for the suspended material additional factors are involved. Due to the evaluation of characteristic parameters a continous simulation of the bed load is possible. The principle of this method is outlined for the case of the Pitzbach and the results gained are presented.