overflow
漲 centers on water rising and spreading beyond its usual bounds: overflowing, surging, or brimming over.
漲 combines 氵 (water) with 張, which likely contributes both sound and the idea of stretching or expanding, suggesting water swelling and overflowing.
Water 氵 stretches and expands like a drawn bow 張, rising until it overflows its container.
For チョウ, imagine a long-serving chief named Chou watching the river overflow its banks: Chou -> チョウ, and the water keeps rising.
to rise high (of water); to overflow; to swell