उभँ = चंद्र बिंदी
up steady/ground inside/surfacce/outside/pull/push = silting
up steady outside = post appearing steady above water at द्वि मात्रा - sense of वचन. Ground steady above water on shore side is भू on sea side is उभ

पूरण = पूर् + ल्युट्
noun(leg up water below)