Watersheds

What is a watershed?


A watershed is the entire land area from which water drains into a particular surface water body such as a lake, stream, or river.

Do you live in a watershed?


Trick question. We all live in a watershed. No matter where you live, you live in a watershed. That’s because everywhere rain falls or water flows over the land is part of a watershed. Watersheds can be big or small. Bothell is split into two major watersheds and a number of sub-basins: The Sammamish Watershed covers the majority of the city, and the Lake Washington/Cedar River Watershed covers the southernmost parts of the city. 

Watershed boundaries are defined by the elevation of the land, with the highest elevation points, “ridges,” marking the boundary of a watershed. These ridges are also called, “divides.” The Continental Divide of the U.S. for example, is in the Rocky Mountains. All the rain and snow falling on the west side of the divide flows into the Pacific Ocean. All the rain and snow falling on the east side of the divide, sooner or later, ends up in the Atlantic Ocean. All water is connected. Simple choices in our daily activities affect the quality of water that we drink and the water that fish and other wildlife rely on.
Learn about salmon habitat conservation efforts in our watersheds.

Watershed Model from Drain Rangers Curriculum

Watershed Model

Water cycle

Excerpt from King County's website
"In a watershed, the rain, the rivers, the lakes and wetlands, even our drinking water are all parts of an intricate cycle. Rain falling on the land soaks into the earth; some runs off to streams; some evaporates before it reaches the earth. The water that soaks into the ground becomes part of the groundwater and feeds streams and wetlands and supplies much of our drinking water. Surface runoff forms streams, then rivers that eventually empty into Puget Sound. Rivers are the sign that the cycle is working...returning water to the oceans where it evaporates, forms clouds, and falls again."

We all live downstream.