ditch
洫 centers on a man-made channel for water: a ditch or trench used for drainage or irrigation.
洫 combines 氵 (water) with 血, which likely contributes the sound キョク and suggests a channel or conduit, forming the idea of a water ditch.
Water 氵 flows through a blood-like 血 channel: imagine a narrow ditch carrying water like veins carry blood.
For キョク, picture a curved ditch shaped like a giant letter 'K' that you walk: 'K walk' -> キョク, and the water flows through the K-shaped trench.