A watershed is any land that drains into a river, lake, stream, or other body of water.  A watershed includes the body of water and its surrounding land.

    It means that YOU live in a watershed.  Watersheds are all around you. Everything including houses, farms, ranches, forests, towns and even cities are all part of a watershed. That’s because all of these things help to transport water, whether through ground water or surface water that flows directly to rivers and lakes.  This includes runoff water that forms a tiny river in the gutters along roads.  It is traveling to another body of water or sinking into the ground.  When it sinks into the ground, it becomes groundwater that is also traveling downhill to a body of water--like a lake or stream.
    There is no watershed in the world that does not have some sort of contamination. Fertilizers and pesticides used in farming travel to a watershed and contaminate it.   This impacts the aquatic wildlife that lives there.   Decades of food chains have been ruined this way.  Water contamination on the surface can spread quickly throughout the entire watershed.  Water that sinks into the ground and becomes groundwater can spread this contamination even more.  Since our drinking water comes from watersheds, we need to be very careful about what goes into it.
    Humans can change a watershed with the littlest action.  When we change natural bodies of water for our own use, we change the watershed.  People build dams for hydroelectric power. A dam may change the habitats of the river or stream that they are on.  Small things like clearing land, building a house or mall, farming, using chemicals on yards, and building a factory can make large changes to a watershed and the water in it.  There are pros and cons to think about before changing a watershed. 
    Watersheds have to be protected and kept healthy.   Since a watershed is the system that moves water to rivers, lakes, streams, or oceans, it means that a contaminated watershed will spread that contamination to clean bodies of water which then become contaminated.  Keeping watersheds protected and clean is a benefit to you and me.
    Watersheds are very important.  The New York City watershed system has eighteen upstate reservoirs and three controlled lakes that cover some one thousand-nine-hundred square miles in the Catskill Mountains and east of the Hudson River.  Taking care of your watershed is protecting your supply of drinking water.