Abstract: River ice, as a vital component of the terrestrial cryosphere, alters the structure of under-ice flows during its evolution.The hydraulic regimes of ice-affected streams may be classified as fully-open, completely-covered, and partially-covered.Using experimental measurements from an acoustic Doppler anemometer, the turbulence characteristics of steady uniform flow under three different hydraulic regimes were studied in terms of streamwise velocity, Reynolds stress, and turbulence intensity.The results showed that for the completely-covered case, the streamwise velocity profile exhibits an asymmetric -shape with the maximum value closer to the smooth boundary, the Reynolds stress profile is linearly distributed in the depth direction, and the turbulence intensity profile for two flow layers based on the two-layer hypothesis may be described by an index relationship.The flow structure in partially-covered channels shows a combination of hydraulic characteristics from fully-open and completely-covered flows.Owing to the effect of lateral momentum transfer, the vertical profiles of the Reynolds stress and the turbulence intensity in the under-ice, open-water, and transition subsections differ from each other.The experimental results can provide theoretical guidance for ice-related disaster prevention and water supply security.