gush forth, surge
洶 centers on water moving forcefully and suddenly: gushing forth or surging. Both meanings describe a powerful, outward rush of liquid.
洶 combines 氵 (water) with 匈, which likely contributes the sound and carries a sense of agitation or turbulence. The exact historical development of 匈 within this character is uncertain.
Water 氵 on the left and 匈 on the right: picture a turbulent chest 匈 of water, heaving and gushing forth like a powerful surge.
For キョウ, imagine a sudden surge of water in Kyoto (キョウト) during a storm: the city name cues キョウ, and the water gushes through the streets.