Continuous measurements of bedload transport rates in a small glacial river catchment in the summer season (Spitsbergen)

Abstract

The study on bedload transport was conducted on the gravel-bed Scott River catchment with a glacial alimentation regime, located in the NW part of the Wedel Jarlsberg Land (Spitsbergen) with subpolar climatic conditions. In the melt season of 2010, bedload transport rate was continuously monitored at 24-hour intervals by means of four River Bedload Trap devices aligned across the width of the channel. The maximum bedload transport rate varied strongly at portions of the cross section from 16 to 152kgm−1d−1 in cross-profile I (c-p I) and 4 to 125kgm−1d−1 in cross-profile II (c-p II). The maximum channel-mean bedload transport rate (qa) amounted to 54kgm−1d−1 (c-p I) and 35kgm−1d−1 (c-p II). Mean daily bedload discharge (Qb) was estimated at a level of 97kgday−1 (c-p I) and 35kgm−1d−1 (c-p II), and the total bedload yield was determined at approx. 4345kg in the measurement period (2086kg — c-p I; 2203kg — c-p II from 13.07 to 10.08). The analysis of the relationship between channel-mean bedload transport rate and water velocity or shear stress revealed a significant value of the correlation coefficient (R2=0.6). Discharge and rate of bedload transport were dependent on the weather and number of days with flood discharge. Approx. 58% of the entire discharged bedload was transported during 3 violent ablation–precipitation floods. Bedload grain size distribution was right-skewed and showed moderate sorting.