灌漑
かんがい · kangai · JLPT N1 · noun
irrigation
💧 灌 (pour water) + 漑 (water fields) = irrigation; both have the water radical 氵
Both kanji contain the water radical 氵 on their left side. 灌 means to pour water onto something, and 漑 means to water land, so together they describe supplying farmland with water.
灌 — water 氵 + 雚 (heron/phonetic)
灌 combines the water radical 氵 with 雚, which depicts a crested heron and supplies the sound 'guàn'. The water component points to the meaning 'to pour' or 'to irrigate', while 雚 is purely phonetic. Originally referring to flooding fields, it broadened to mean pouring liquid, irrigating, or filling something up.