Keeping North Dakota’s lakes and streams clean demands more than dockside
diligence. Even if you don’t live along the shores or banks, you may be
contributing to the pollution of lakes and streams. Lakes and streams are larger
than their shorelines. They’re part of a system called a watershed.
What is a watershed?
Water from rainfall or snowmelt that doesn’t evaporate or soak
into the soil runs into ditches, streams, wetlands, or lakes. The land area from
which the water drains is called a watershed.
Watersheds may vary in size. If water from a few acres drains into a little
stream, those few acres are its watershed. This stream and others like it run
into larger streams or lakes. Small watersheds make up larger ones. It’s easy to
see how the watersheds of North Dakota’s lakes can have land areas many times
larger than their lake surfaces.
A watershed is simply defined as, "an area of land
that drains to a common point, usually a stream, river, lake or wetland".
For more on the basics click these:
Water and People
WATERSHED IQ TEST