Monday was the end of the 20-day sand-washing operation at the Xiaolangdi Reservoir Dam in central China's Henan Province. Sediment-laden water was seen gushing out of the dam as part of the operation that is conducted every year before the flood season to clear out the accumulated mud and sand. Xiaolangdi Reservoir is the largest of its kind on the Yellow River, designed for flood and ice control, dredging, and ensuring water supply and power generation.