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Did you know you are sitting in a watershed right now? Watersheds are everywhere. A watershed is land where water runs off into a body of water such as a river, lake, or bay. A watershed includes the soil, water, air, plants, and animals.
Everyone lives in a watershed. Watersheds can be any size. Watersheds are important for watering crops, drinking water, and shelter for wildlife. Some watersheds can be millions of miles wide. They join together to form systems that drain into oceans. They can cross county and state borders, or even cross over into another country. Many living and non-living things
are found in a watershed and the watershed is always changing. Healthy watersheds are very important for healthy environments. |
A Watershed...
- takes water from the atmosphere and soaks it up in the soil. Water runs downward toward the sea. Many things
effect how fast it moves downward such as the type of soil, climate, and vegetation.
- stores rainwater once it filters through the soil. When the watershed's soils become soaked, the water will filter down deeper or it will run off the surface.
- moves water through the soil that eventually goes into the streams, rivers, and the ocean. It is better if the water is released slowly because if the water is released fast it causes large amounts of run-off. This causes flooding and soil erosion.
The Ground Water Story
The Water Cycle
The water cycle reuses the earth's water.
| Moisture returns to the atmosphere by evaporation. This is the basis for watershed function. |
The Water Cycle
Drawing by Sarah
1. Water falls to the earth as rain, hail, sleet, or snow.
2. Some of this precipitation is soaked up by the ground, but much of it flows downhill into rivers and streams and sooner or later into the ocean.
3. While it is on the surface of a lake or river, or while it flows downhill some of the water evaporates and some of the water transpires.
| Transpiration is the transfer of water from plants into the atmosphere. |
4. During evaporation and transpiration the water vapor moves into the atmosphere. It cools there and condenses. Clouds form and the cycle begins all over again.
Transpiration in Action |
Background by Sarah |
When precipitation falls it runs into small streams. The streams run into rivers. The rivers join together to make larger rivers. Eventually, the rivers run into the ocean.
Streams in a watershed are given an order, or a number based on their position in the watershed. This means that they go from smallest to largest. The smallest streams are called "first order" streams. First order streams have no tributaries.
First-order streams - small stream with no tributaries.
Second-order streams - two first-order streams meet to form a second-order stream.
Third - order streams - two second-order streams join.
Fourth - order streams - two third-order streams join...and on it goes.
What is a tributary?
A tributary is a stream or river which flows into another river or body of water. |
Our watershed is important. Our local watershed is a small part of a much bigger watershed. People like to boat, fish, and swim in water. The people and the wildlife in a watershed depend on it for food, water, and shelter. Everything that happens around a watershed impacts it. If the watershed is not healthy, then people and animals living there are at risk. Also, if the watershed is not healthy the economy suffers.
It flows and flows, but where does it go?
The Mobile River Basin - A Larger Watershed
Drawing by Sarah
Small watersheds are a part of larger watersheds. The larger watersheds are a part of even bigger watersheds. The largest are known as the major river basins. For example, the Cahaba River flows into the Alabama River which joins with the Tombigbee River and forms the Mobile and Tensaw rivers. These rivers flow into the Gulf of Mexico.
Even though Sarah, Daniel, Breanne, Jaylon, and Allie live in different parts of the United States, the streams, rivers, and bays in their watersheds flow into the Gulf of Mexico. Marek's watershed flows into the Black Sea, then to the Mediterranean Sea which flows to the Atlantic Ocean which
eventually meets the Gulf of Mexico!
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