Session 2: Water On the Move

Session 2: Water on the Move

Homeward Bound, Care For a Lift?
After it rains or snows, water trickles or roars across the land towards rivers, lakes, and eventually the oceans. Before the water gets to these places, it has to pass over and through some land. This land is called a watershed. A watershed acts like a giant funnel, directing water downhill in a specific direction. As water runs through a watershed, it picks up all kinds of materials in its path.

Try This!

Clean Water Moves, Dirty Water Moves
Quiz Yourself

Clean Water Moves, Dirty Water Moves

Read to Learn:
Now that you understand the water cycle, it’s time to get your heads out of the clouds and look at the land for awhile. Let’s pay attention to surface waters that run off land in rivers, streams, and creeks, and eventually reach the oceans.

The phase of the water cycle when water flows across the land and forms streams and rivers is called runoff. Runoff occurs when the rainfall rate exceeds the soil’s saturation rate. Most of the water eventually flows into the oceans. At any point, the water may heat up and evaporate back into the atmosphere. (See Session 1, Activity 3)

Do to Learn: Classroom
Investigate a Model Watershed.
You can see how water moves through a watershed by making a model in the classroom. To make the model, follow these steps:

Crumple two sheets of newspaper and place them in the bottom of a box or pan.

Cover the crumpled newspaper with a large sheet of aluminum foil or plastic wrap. Arrange the foil or plastic wrap between the two sheets of newspaper to form a valley, and shape hills over the high places.

Fold up the outside edges of the foil or plastic wrap to stop water from overflowing.

Now you have a model of two hills with a valley between them. By spraying water on the hills, you can see how water drains from land into a stream. You now have a model watershed. In a real watershed, water doesn’t just travel on top of the land, it also gets soaked up by the land and travels under it. Try spraying your model from different directions. Where do you think is the best place to spray the water to see how it drains?

To see how water gets polluted, soak a bit of a paper towel in food coloring. Wad up this paper towel, and place it in the watershed. The paper towel represents a polluted area. Make it “rain” again, by spraying water on the model. Watch how the water running through the watershed picks up the color from the paper towel as it moves toward the valley. This is the same way that water might pick up pollutants and bring them to a stream.

As you investigate the model, think about the following questions:

Where is the water flowing from, and where is it going?
Does all the water flow in the same direction?
How do materials in a watershed get carried to streams, lakes, and oceans?
What is a watershed?

Quiz Yourself

Look to Learn

Take a quiz that can help you explore watersheds at www.ctic.purdue.edu/cgi-bin/KYWQuiz.exe.

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