Watersheds
A WATERSHED (also called a drainage basin or catchment) is all the LAND that drains water to a specific river, lake, or ocean. If you spilled water anywhere in a watershed, gravity would eventually pull it to the same outlet. Watersheds range from tiny (a small creek's area) to huge (the Mississippi River's watershed covers 41% of the US).
Why watersheds matter. (1) Whatever you do in a watershed AFFECTS the water downstream. Pollution, fertilizers, plastic — all flow downhill. (2) WATERSHED MANAGEMENT is increasingly used to protect water quality. Forested watersheds give cleaner water. Concrete watersheds (cities) flush pollutants. (3) Watersheds DON'T match political boundaries — water doesn't care about state lines, requiring cooperation.
You spill paint in your driveway. Heavy rain comes. Where might the paint eventually end up?
Famous watersheds. AMAZON: largest by volume, drains 7 million km² of South America. MISSISSIPPI: 31 US states drain into it. NILE: world's longest river system (in dispute), drains much of northeast Africa. Watersheds connect us across enormous distances. Cities downstream depend on practices upstream — sometimes thousands of miles away.
Find Your Watershed
Look up "what watershed do I live in" with your city. EPA's "Surf Your Watershed" tool is useful in the US. Once you know yours, notice how everyone in it shares one water destiny.
You live in a watershed. Your actions are part of a larger system. Caring for watersheds is caring for water — and for everyone downstream.
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