河内[hanoi] Hanoi
運河[unga] canal
応急渡河[oukyuutoka] hasty crossing
黄河[kouga] Yellow river (in China)
河港[kakou] river port

河鹿[kajika] kajika frog (Buergeria buergeri)
河床[kashou] riverbed
河水[kasui] river water
河川[kasen] rivers
河童[kappa] kappa (mythical water-dwelling creatures)

汚染源[osengen] source of pollution
音源[ongen] sound source
禍源[kagen] source of misfortune
供給源[kyoukyuugen] source of supply
経営資源[keieishigen] management resource

源氏物語[genjimonogatari] the Tale of the Genji
源泉[gensen] source
源流[genryuu] current-limiting
語源[gogen] word root