What is a watershed?

Watershed... the word means a parting, a shedding of waters. But a watershed is a gathering place, also. It is a place where hills and plains and people's lives are connected by falling rain and flowing water.

A watershed is measured by the hilltops and ridges that are its boundaries. It is shaped by the hills, valleys and plains that are the landscape and is tempered by the forests, fields, lakes, and marshes that are habitats for its creatures. Most of us know a watershed through its streams and rivers that connect forest with farm, farm with city and city with Puget Sound... and each of us changes the watershed day by day, bit by bit, as we go about the business of our lives.

Water cycle

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 ever 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 to Puget Sound. Rivers are the sign that the cycle is working... returning water to the oceans where it evaporates, forms clouds, and falls again.

Watersheds and people

A change in the watershed affects our lives... a change that we make in the landscape affects the watershed. It's all connected. Nature's changes can be as quiet as branches building up behind a fallen log and changing the path of a stream. Or they can be as dramatic as a winter flood. Our actions, too, can be subtle or very dramatic... but they all affect someone or something. When we cut forests, clear land, lay concrete and asphalt, and build houses and towns we cause changes in the watershed. Those changes mean the water cycle works differently.

Rain striking the ground has fewer places to soak in gradually... runoff is faster and more violent... causing erosion and flooding. Water quality worsens as water drains from cities and farms carrying pollutants such as tire dust, firefighting foam, pesticides, animal waste, oil and heavy metals into our groundwater, streams, and eventually, Puget Sound. Well water can become unhealthy to drink. Streams and fish habitat are damaged. Salmon, especially, have difficulty surviving when streams run faster and streambanks are cleared.

The watershed, the water cycle and our lives are all connected. Any action, anywhere, affects the land, the water, and ultimately, us. We All Live Downstream.

Watershed words:

• Headwaters: Source of a stream.
• Watershed: The land from which rain collects and runs to a single point.
• Groundwater: Water that lies beneath the earth's surface.
• Stormwater: Water rinses the watershed into streams, rivers, lakes and Puget Sound
• Infiltration: The slow movement of water from the surface to the groundwater.
• Hydrologic: Related to water in all its forms.
• Aquifer: An underground water supply flowing through sand and gravel.