Experimental investigation of sediment transport in partially ice-covered channels

Abstract

It is important to understand the effects of ice cover on sediment transport in cold climates, where sub-freezing temperatures affect water bodies for a significant part of the year. The literature contains many studies on sediment transport in open channel flow, and several studies on sediment transport in completely ice-covered flow. There has been little or no research on sediment transport in partially ice-covered channels. In the current study, laboratory experiments were done in a rectangular flume to quantify the impact of border ice presence on the sediment transport rate. The effects of ice cover extent and changing flow strengths on sediment transport distribution also were investigated, and the results were compared to those for fully ice-covered and open channel flow. The ice coverage ratios considered were 0 (representing the open water condition), 0.25, 0.50, 0.67, and 1 (representing fully ice-covered flow). The partial ice cover was found to impact the sediment transport distribution within the channel. The effect of ice coverage extent on sediment transport distribution was more significant at lower flow strengths and became negligible at higher flow strengths. The conventional equations for sediment transport in open channel flow and fully ice-covered flow that relate the dimensionless bedload transport rate to the flow strength were found to be applicable to estimate the total cross-section-averaged bedload transport for partially ice-covered flow when modified appropriately. Empirical coefficients for these equations were determined using the experimental data.