A watershed is the area of land that drains (sheds water) to a stream or system of streams.
Watersheds can be large or small and smaller watersheds are nested within the larger watersheds. For example, the Columbia River watershed runs from British Columbia in Canada to the river's mouth at the Pacific Ocean and includes all the streams and rivers that feed into the Columbia River. On a smaller scale, each stream or river within the Columbia River watershed also has its own watershed - the area of land that drains only to it.
Clark County, with its abundance of streams, has eighteen major watersheds. Each watershed is further divided into sub-watersheds or sub-basins, often named for the small creeks and tributaries that feed into the main stream.
To learn more, the Clark County Stream Health Report provides a comprehensive overview of the condition of Clark County streams, rivers and lakes.
