headwater
nounUK /ˈhɛdwɔːtə/
US /ˈhɛdwɔtər/
A headwater is the small stream where a river begins.
The hikers followed the headwater up the mountain to find where the river starts.
OTHER MEANINGS
2. The upper part of a river system, near its source.
The headwaters of the Amazon are found high in the Andes.
3. Water that flows into a larger body of water from its source area.
Pollution in the headwater affects the whole river downstream.
4. The beginning or earliest stage of something.
The small club was the headwater of a nationwide movement.