The transport of sediments by released anchor ice

The impact of sediment transport by anchor ice release on the annual sediment budgets of rivers is unknown. Sediment transport on regulated rivers could be significant since open water persists throughout the winter season and anchor ice forms and releases often. Studies that quantify the amount of sediment carried or rafted by released anchor ice pans are rare and have been performed on unregulated rivers with significantly different flow regimes, or have few collected samples. In this study, anchor ice samples were collected on three regulated rivers in Alberta: the North Saskatchewan, Peace and Kananaskis River. Previous studies on the amount of sediment contained in anchor ice are discussed and compared. Gravel and cobble sized particles were also sampled from anchor ice pans as they floated by to better understand the largest sediment anchor ice transports. The sampled gravels and cobbles contained in anchor ice showed that 24% of the total sampled mass came from only 1.2% of the particles sampled. The average sediment concentration contained in released, floating anchor ice was found to be 28.2 g/L, with a standard deviation of 33.2 g/L, and a median of 18.4 g/L. This information will allow for more accurate estimations of how transport of sediment by anchor ice releases affects the annual sediment budget on regulated rivers.