The processes that are both artificial denudation and artificial accumulation to original geomorphy were uninterrupted, and original geomorphy was eroded by floodwater.

• 我国绝大多数挡水工程仍是各种土料堆筑而成,它们在抵御洪水突袭时,常有渗漏穿孔险情发生而使人措手不及。