Trans-Amazon Expedition

Watersheds

Water is always moving. Because of gravity, water always finds the lowest spot on a given surface and collects there, just like puddles form when it rains. Think of a watershed as a bathtub. Any water that hits the walls or sides of the bathtub collects in the bottom of the tub. This is similar to what happens in a real watershed. If rain falls anywhere in the watershed, it will flow downhill until it reaches a stream, river, pond or other type of water body. Generally watersheds are named for the major rivers that carry the fresh water to sea.

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Fishing is one way that local people have an impact on the water in their watershed.

Together, watersheds provide all of the Earth's freshwater systems. In order to ensure the quality of drinking water and successful habitats for animals and plants, watersheds need to be healthy and clean. Because water travels such great distances, it's important to remember that pollution is often carried those distances as well.

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The Amazon watershed flows through 6 countries; Peru, Bolivia, Ecuador, Venezuela, Columbia, and Brazil.

To find out what watershed you live in, you'll need to find a map of North America. Locate where you are on the map and look for rivers nearby. Now, trace the river or stream to a larger river. Once you find a larger river, continue this process until you are able to trace the water all the way to Pacific Ocean, Atlantic Ocean, or the Gulf of Mexico.

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The Amazon River sends a huge plume of silty freshwater out into the Atlantic Ocean. This satellite image shows the brown water from the Amazon mixing with the blue ocean water.

The Amazon Watershed is the largest watershed in the world. In fact, the Amazon watershed is responsible for maintaining and transporting 20% of the world's fresh water that drains into an ocean. It covers an area of more than 7 million square miles in 6 South American countries: Peru, Brazil, Bolivia, Ecuador, Columbia, and Venezuela. There are thousands of tributaries (smaller rivers that feed a larger river) throughout the Amazon watershed. However, even the tributaries in the Amazon can be seriously big rivers. Seventeen of the Amazon's tributaries measure over 1,000 miles in length! The tropical rainforest that makes up the Amazon watershed is the largest and wettest in the world.

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Everyday the river get larger as more and more rivers empty into the main river. We are still over 1,000 miles from the ocean and the river often over 2 miles wide.

The Amazon watershed is able to drain such a large part of South America because of its geography and topography. The Amazon Basin is like a giant saucer tipped toward the Atlantic Ocean. The reason the water is able to travel such a great distance is because there aren't any other mountain ranges in the way between the Andes and the ocean. What do you think would happen if there were mountains?

Here are some amazing facts about the Amazon watershed:
--It is estimated that the Amazon discharges between 9 million and 32 million gallons of water per second.
--During flood stage, the Amazon River can be 30 miles wide.
--73% of the Amazon watershed is covered by tropical rainforest, more than any other watershed on earth.
--There are over 3,000 species of fish alone that live in the Amazon watershed - more than are found in the Atlantic and Pacific Oceans combined.
--There are no bridges that cross the Amazon River.
--The Amazon is one of the least populated areas on earth, with only an average of 4 people per square mile living in the region.
--The Amazon watershed is home to more than 2 million insect species, 200,000 plants and more than 800 mammals, many of which are found nowhere else in the world.