No matter where you live, work or play, you live in a watershed. Wildlife lives there, too. A watershed is an area of land that water flows across or through on its way to a particular water body, such as a stream, river, wetland, lake or coast. Think of it as the land upon which precipitation (such as rain) falls and flows to a common, watery place.
Your Backyard Watershed
Even your backyard is a watershed. Next time it rains, notice how rainwater moves across the land. Some is absorbed by the earth and refreshes thirsty plants and creatures. Some fills up and stays in holes, creating puddles until it evaporates. What’s left over keeps flowing until it drains into a common place like a river or lake. If rainwater (or melting snow) in your neighbourhood flows into the same watery spot, you and your neighbours, including wildlife, likely share the same watershed.
Discover Your Watershed Address
You can tell watersheds apart by their boundary. Ridges (or high areas such as hilltops) form a natural boundary of a watershed from which water drains either toward or away from a particular watershed. Some watersheds are tiny, only a few hectares in size. The largest are gigantic, millions of square kilometres large.
Canada has five main watersheds: the Arctic, the Atlantic (which includes the Great Lakes and the St. Lawrence River), Hudson Bay, the Pacific and the Gulf of Mexico. Each of these massive landscapes contains a network of sub-watersheds, most of which are connected through configurations of tributaries (streams and rivers) that channel water to an ocean. Discover your watershed “address” within one of these five areas by locating your home on the handy Watershed Map.
Open or Closed Systems
Most watersheds in Canada are called “open systems” because they eventually drain into an ocean. If water within a watershed can only escape through evaporation or by seeping into the earth, it’s called a “closed system,” such as Redberry Lake in Saskatchewan.
Groundwater is Part of a Watershed
Water beneath the ground is called groundwater. Like the water on the ground’s surface, groundwater drains into water bodies such as streams, lakes, rivers and the ocean — but the process can take 10,000 years or more! Groundwater can also discharge as a spring or a flowing well.