weir, fish trap, (kokuji)
簗 centers on a structure placed in water to catch fish: a weir or fish trap. It is a kokuji, created in Japan for this specific fishing device.
簗 is a Japanese kokuji combining 竹 (bamboo) and 梁 (beam, weir), reflecting a bamboo fish trap or weir. The exact historical development is uncertain beyond this component combination.
Bamboo 竹 beams 梁 are tied together to form a fish trap in the river. Picture a lattice of bamboo poles guiding fish into the weir.
For リョウ, imagine a fish trap so effective it catches a whole 両 (りょう, both) of fish: 両 -> リョウ, and the bamboo weir holds them all.