Abstract
We investigate the impact of ice coverage on flow and bed shear stress
profiles in a river bend. We perform field measurements using Acoustic
Doppler Current Profiler (ADCP) in a bend of the Red River, North
Dakota, the United States. Field campaigns were carried out under both
open surface and ice-covered conditions in 2020 and 2021. Our results
show that the time-averaged velocity profile follows closely the quartic
solution of Guo et al. (2017) under full ice coverage. While the flow
profile under open-surface condition follows closely the logarithmic law
near the bed, it is challenging to identify the logarithmic layers in
our measured data under ice-covered condition. Our results also show
that the impact of ice coverage is most significant near both banks
where the vertical velocity profile is modified significantly due to the
interaction of turbulent flows with the ice cover. Our results suggest
that the bend curvature and ice coverage both have significant impacts
on the velocity profile as well as the distribution of the bed shear
stresses. Our findings provide new insights on sediment transport
processes of ice-covered rivers, especially during the break-up period
when the surface coverage changes rapidly.