灌 often implies pouring with force or filling a container. 灌酒 means to pressure someone into drinking. 灌水 online means to spam or post meaningless content.
Three-drop water radical on the left - the side-stacking form of 水. Anchors 灌 in liquid-handling verbs: pouring, irrigating, force-feeding. The action is always volumetric: not a drip but a flood, a steady stream into something.
Right 雚 supplies the sound exactly - guàn → guàn, a perfect match. 雚 is a wading bird (heron/stork), and the same phonetic appears in a useful family: 罐 (jar), 鹳 (stork), 观 (view), 劝 (advise) - all share the rime.
