運河
うんが · unga · JLPT N2 · noun
canal
🚢🌊 運河 = carry (運) + river (河): a river built to carry boats
運 means transport, as in 運送 (shipping), and 河 means river. A canal is a man-made river whose whole job is carrying cargo. Hook for the sound: unga sounds like un-gah, the noise a bargeman makes hauling a load.
河 — water radical 氵 + 可 (kě, phonetic)
河 is a classic semantic-phonetic compound: 氵 (water) gives the meaning 'river', while 可 supplies the sound. Originally 河 referred specifically to the Yellow River, and only later broadened to mean rivers in general.