In the classics, water running wild and overflowing is called 洚水.
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history
洚 is not used alone in modern Chinese; it appears in classical texts almost only as 洚水 (a great flood, the deluge), and is also read hóng in some old readings. It is the water radical 氵 plus the phonetic 夅, the element also inside 降 and 绛.
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Classical only; modern Chinese uses 洪水 and 泛滥 for floods.
