Watersheds 101

What is a watershed?

A watershed (or basin) is the area of land where all of the water that is under it or drains off of it goes into the same place either a lake, marsh, stream, river or groundwater. A watershed is often named after the river that flows within it. For example, all the land within the Nechako Watershed flows into the Nechako River, either directly or via a sub-basin.

A sub-basin is a watershed within a watershed - a smaller river drainage. For example, Murray Creek is a sub-basin within the Nechako Watershed. The land within the Murray Creek watershed flows into Murray Creek, but is within the overall Nechako Watershed. Murray Creek is a tributary to the Nechako River.

A tributary is a river that flows into another river or a lake. It does not flow directly into the sea or ocean. The Nechako River is a tributary to the Fraser River. The Fraser River is not a tributary to any other river.