Konnichiwa Novah-san! Elizabeth-san!
"Cataract" or "Torrential cascade" is "Taki" in Japanese. Because Japanese "Taki" has two meaning, "Cataract" and "fast flowing rapid".
And "Suikou" meaning "the flow of water" in Japanese. "Sui" is "Mizu/water" and "Kou" is "Iku/go". But usually, Japanese don't use this word "Suikou", Japanese use "Kyuuryuu" or "gekiryuu".
NANGI