Under Cover Transport and Accumulation of Frazil Granules

Abstract

The process of frazil jam evolution in ice-covered rivers is not well understood. In this paper, under cover transport of frazil granules and its relation to frazil jam evolution in rivers are studied. A concept of ice transport capacity by analogy to bed sediment transport is developed and validated with the field data obtained from the Hequ reach of the Yellow River. The analysis of field data shows that the ice-transport capacity can be described by existing bed load transport formulas for low-density sediments. In view of various shapes of frazil granules that can form in different rivers, the effect of particle shape on the transport capacity is studied. Laboratory experiments are carried out using low-density chips to determine the transport rate over a wide range of flow conditions that are applicable to frazil transport. A generalized cover load transport formula taking into consideration the shape of the particles is obtained based on the laboratory data.