The source of a river or spring; the place where water originates or emerges; a water supply source.
この川の水源は山の高い所にあります。
The source of this river is high in the mountains.
地域の水源を守るために森林の保護が重要だ。
Protecting forests is important to safeguard the area's water sources.
ダムは下流の水源を安定させる目的で建設された。
The dam was built to stabilize downstream water supply.