Every reservoir has a "maximum possible floodwater volume" [flow volume during peak flooding]. Back in 1963 when Shihmen had just been built, we hit Supertyphoon Gloria, and the floodwater volume rapidly approached the upper limit, which gave the American engineer in charge of the design quite a fright. Therefore, in the following 20 years two flood drainage pipelines were added to prevent the dam capacity from being overwhelmed.
每個水庫都有一個「最大可能洪水量」（洪峰流量），石門在民國 52 年剛建好時，就碰到超級強颱葛樂禮，洪峰流量就快逼近水庫的上限，讓協助設計的美國工程師嚇一大跳，因此在之後 20 年間新增了 2 座「排洪隧道」以預防潰壩。