流域

りゅういき

Common word

noun

•

drainage basin, catchment basin, river basin, watershed, valley

流	current, a sink, flow, forfeit
域	range, region, limits, stage, level

はげ

あめ

りゅういき

こうずい

The heavy rain brought floods in the valley

き

りゅういき

おおみず

およ

The dam gave way and sent a great flush of water down the valley