sediment disasters in the Heshe River. For example, the sediment input during Typhoon Morakot in 2009 which accounted for 95.8% of the annual sediment discharge is the most serious of these disasters. Since Typhoon Morakot, the sediment input has decreased, as there have been less serious typhoons and rainstorms, thus, transforming the river morphology from a braided river into meandering river. In addition, river bends and topographical notches restrain sediment from moving downstream and store it in these locations. These factors have indirectly increased the erosion density of the river banks by 2.5 to 10.5 times.
Key Words : Heshe River watershed, macro-sediment impulse, river morphology.