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Based on the data from 159 events at the Tongguan station on the Yellow River, we have found the rule to describe the complicated relationship between the fill-scour features and the event-maximum suspended concentration (C_max). The depth of scour is large if the C_max is low. and is small if C_max is high. However, if C_max increases to the ranges of hyperconcentrated flows, scour occurs again. Controlled by the foregoing complicated fill-scour behaviors, the channel adjustment of the Yellow River is also complicated. When the suspended concentration is low, channel scour occurs, and thereby the channel shape tends to be narrower and deeper, and the thalweg more sinuous. When the suspended concentration increases, channel fill occurs, leading to an increase in the channel width-depth ratio and a decrease in the channel sinuosity. However, when the suspended concentration further increases and exceeds a certain threshold, channel scour occurs again, and the adjustment of channel morphology turns to the opposite direction. The rules outlined in the paper for the channel adjustment of the lower Yellow River may provide a new thinking for the regulation of the channel morphology of the lower Yellow River after the closure of the Xiaolangdi Dam, through the regulation of the lower Yellow River’s water and sediment by choosing some specific operation modes of the reservoir Either by releasing clear water or by releasing man-made hyperconcentrated flows, the downstream channel may tend to be narrowed, deeper and more sinuous.
Based on the data from 159 events at the Tongguan station on the Yellow River, we have found the rule to describe the complicated relationship between the fill-scour features and the event-maximum suspended concentration (C_max). The depth of scour is large if the C_max is low. and is small if C_max is high. However, if C_max increases to the ranges of hyperconcentrated flows, scour occurs again. Controlled by the foregoing complicated fill-scour behaviors, the channel adjustment of the Yellow River is also complicated. When the suspended concentration is low, channel scour occurs, and thereby the channel shape tends to be narrower and deeper, and the thalweg more sinuous. When the suspended concentration increases, channel fill occurs, leading to an increase in the channel width-depth ratio and a decrease in the channel sinuosity. However, when the suspended concentration further increases and exceeds a certain threshold, channel scour occurs again, and the adjustment of channel morph ology turns to the opposite direction. The rules outlined in the paper for the channel adjustment of the lower Yellow River may provide a new thinking for the regulation of the channel morphology of the lower Yellow River after the closure of the Xiaolangdi Dam, through the regulation of the lower Yellow River’s water and sediment by choosing some specific operation modes of the reservoir Either by releasing clear water or by releasing man-made hyperconcentrated flows, the downstream channel may tend to be narrowed, deeper and more sinuous.