After gullies are formed, the stability of hillside soil deteriorates;consequently, a large quantity of sediment is produced by the interaction of incision, lateral erosion and headcut retreat.

• 同时蚀沟形成后即会因下切、横向冲蚀与溯源冲蚀之同时扩张，而使坡面之稳定条件急剧破坏，造成大量的土砂冲刷。