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

• Study shows the temporal and spatial variability of bedload flux in the Arctic river.
• Possibility to apply the RBT measurement device and its efficiency were verified.
• Maximum daily bedload transport rate was 66 kg m− 1 d− 1.
• Total bedload yield amounted to 4345 kg in the measurement period (45 days).
• Condition of very coarse gravels motion (v > 1 m s− 3; τ > 7 N m− 2) was determined.

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 152 kg m− 1 d− 1 in cross-profile I (c-p I) and 4 to 125 kg m− 1 d− 1 in cross-profile II (c-p II). The maximum channel-mean bedload transport rate (qa) amounted to 54 kg m− 1 d− 1 (c-p I) and 35 kg m− 1 d− 1 (c-p II). Mean daily bedload discharge (Qb) was estimated at a level of 97 kg day− 1 (c-p I) and 35 kg m− 1 d− 1 (c-p II), and the total bedload yield was determined at approx. 4345 kg in the measurement period (2086 kg — c-p I; 2203 kg — 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.