What is a headwater stream?

Headwaters are the first channels in a drainage network, often fed by springs, rainfall, snowmelt, or melting glaciers. They are usually narrow, shallow, and ecologically important because they influence water quality and flow downstream. Many headwater streams are seasonal, but they can still supply a large share of a river’s water over time. Protecting headwaters matters because pollution or land disturbance there can spread throughout the basin.