Note: Teacher’s notes are in red

“Shedding Light on Watersheds”

Through discussion, construction of model watersheds, and online activities, students will discover the importance of watersheds and the great impact humans have had on watersheds.

Your Mission

Take care of the water that takes care of you!

One of the most vital things in the area in which you live is a shed—a watershed. The system of creeks, streams, and rivers that wander through the landscape provides drinking water, electricity, and food, to name but a few of its benefits. Your mission: Learn to take care of your watershed, because you depend on it.

Subjects: Geography, Science

Relevant U.S. National Geography Standards: 7, 14, 15, 18

Materials

Students will break into groups of three or four. Each group will need:

Bucket

Collection of large and small rocks, chunks of wood, or boxes

Markers

Plastic foam peanuts

Several sheets of aluminum foil or large plastic garbage bags

Shallow washbasin, washtub, or dishpan

Sprinkling can or spray bottle

Introduction to Watersheds

Introduce the term “watershed.” Lead a discussion about how people have used and changed watersheds.

A watershed is an area of land from which rainwater and snowmelt drain into a particular river, stream, or lake. The entire central portion of the United States is one watershed, draining into the Mississippi River. For humans, watersheds provide water for irrigation, drinking, recreation, flood control, and hydropower; for other living things, such as plants, animals, fish, aquatic insects, and waterfowl, watersheds provide habitats, or places to live.

Humans have had a huge impact on watersheds. We have built reservoirs for water supply and hydropower; straightened and channeled streams for flood protection; developed towns and cities along primary waterways; and taken water to irrigate dry farmlands. As a result, watersheds have experienced degradation of water quality from urban pollution and agriculture; reduction of streamside vegetation; and general degradation of aquatic and riparian ecosystems.

Management 101

Online, students can manage urban, suburban, and rural watersheds at “The Watershed Game,” from the the Bell Museum of Natural History, at http://www1.umn.edu/bellmuse/mnideals/watershed/. This interactive activity works best when each student has his or her own computer. After students complete the activity, hold a class discussion about what they’ve learned about watersheds.

If students can’t access a computer, print out the “Watershed Information Sheet” from PBS Online at http://www.pbs.org/kuat/grandcanyonflood/watershed
worksheet.html

If you have only one computer in the classroom, lead students in finding their watershed at the Environmental Protection Agency site (http://www.epa.gov/surf3/).

Watersheds can be complex, multifaceted systems that serve a variety of needs for thousands of people. They also can cross political boundaries, so the people who manage them must take into account a broad swath of economic, political, industrial, ecological, and cultural variables. Clean, fresh water is vital to life today, tomorrow, and 100 years from now. When you learn about the functions of a watershed and about what watersheds need to be sustainable, you begin to acquire the necessary intellectual tools to take care of fresh water.

If you’re a beginner, one way to acquire these tools is at the novice level of “The Watershed Game” at the Bell Museum of Natural History, at the University of Minnesota Web site (http://www1.umn.edu/bellmuse/mnideals/watershed/). Then go to the intermediate level and see if you can make intelligent choices to ensure a healthy watershed.

The Shape of Things to Come

To prepare students to build model watersheds, explain the physical components of watersheds and their characteristics. You may want to print out a diagram of drainage patterns (see Student Related Web Sites). Discuss

stream flow shapes, such as meandering and braided;

stream flow drainage patterns, such as dendritic, trellis, and radial;and

stream order. (A first-order stream is a headwater stream; it has no tributaries. Once this stream joins with another stream, the newly formed stream is called a second-order stream. A third-order stream is formed when another stream joins the second-order stream, and so on.)

Divide students into groups of three or four. Set out all materials students will need to build their watersheds. Students will create models of watersheds to observe how they form. Assist students as they build and experiment with their models.

You’re going to play a word association game with the following words: “braided,” “radial,” “deranged,” and “ trellis.” Did you think: “hair,” “tires,” “crazy,” and “garden”? Strangely enough, “braided” and the other words also refer to the shapes or drainage patterns of streams! Watersheds are made of many different components.

Watershed Models and Model Watersheds

Each group should have access to all instructions for building the watersheds (student activity under “Watershed Models and Model Watersheds”), so each group can work at its own pace. Print the instructions for students, write them on the blackboard, or have students refer to instructions online.

Look under Extension Activities for additional questions to ask students as they’re building their models.

With a group of classmates, you’re going to create models that will demonstrate some of the variety found in watersheds. To build your first watershed, each of you in the group will have a task:

one person should collect the materials from the materials table,

one person should read the instructions aloud,

one person can be “foreperson” in charge of building the first model, and

one person can “make it rain.”

In a shallow basin, arrange rocks, wood, or boxes higher on one end of the basin than the other. Cover the rocks with aluminum foil or plastic bags. Press and mold the foil around the rocks to create a miniature landscape. Make sure the edges of the foil or bags remain inside the tub—or else you’ll create a waterfall! Your model will look as though you’ve filled the basin to the rim or higher with lumpy mashed potatoes, then shoved half the potatoes to one end into a lumpy mountain.

Use the marker to draw the place where you believe the main rivers will flow. Then use a spray bottle to make it “rain” over the land. What happens to the water? Do streams form? How many? Where do they form? Count the number of small watersheds that drain into the main river you drew with the marker. Notice how all the water flows towards one end of the tub. Remove the foil from the rocks, remove the rocks from the tub, and empty the “rainwater” into a bucket.

After students have made their “double watershed” models, point out how water runs down one side or the other of the ridges and forms rivers in the valleys. All the area drained by a river system is that river’s watershed. Ridges divide individual watersheds. Explain that each small stream is formed by its own watershed. As streams join together, their combined watersheds and stream flow form larger watersheds and rivers.

Switch tasks within your group and make another watershed model. This time, rearrange the rocks in the tub to try to create a model that illustrates two different watersheds. Both watersheds should drain into a lake at the lower end of the container.

Have each student place two of the foam peanuts on flat locations in the watershed. The peanuts will represent houses. Have one student rapidly spray nine pumps of water on the upper portion of the watershed. Explain that rapidly spraying a large amount of water creates a flood in the watershed. Observe the houses during the “rainstorm.” Ask questions such as:

Did the flood cause different amounts of damage to the houses (such as causing them to move) based on the location of the houses in the watershed?

Were any houses washed away by the flood?

Where would you want to build your own house?

How many watersheds are above the lake that forms at the bottom of the model?

What happens to the size of the streams as the watersheds get larger?

Your watershed looks like a nice place to live. Why not build some houses there? Team members should switch tasks again. Then place two foam peanuts (your “houses”) on flat locations in the watershed. The “rainmaking” student should rapidly spray nine pumps of water on the upper portion of the watershed. Observe the houses.

Where, Oh Where Is My Watershed?

Lead a class discussion about the watershed in the students’ area. Where does the watershed begin? Where does it end? Are students aware of any issues surrounding the watershed—pollution, overdevelopment, rechanneling of its waters?

Local, state, and national organizations work to preserve large rivers, reservoirs, and aquifers. They have their work cut out for them, for humans have impacted watersheds in many negative ways. But individuals can have a positive impact on watersheds too, particularly on their own, local watershed. Speaking of which, where’s your “shed”? And what does it need to stay healthy?

Taking Action: Make Yours a “Model” Watershed!

The good news is that everyone can help restore or protect a nearby creek or stream. If you monitor your local streams, you can learn about upstream activities in your watershed. Remember: It’s crucial to keep the watershed clean for the people who live downstream!

Join the “Global Water Sampling Project.” Work with other students online to test fresh water throughout the globe (http://k12science.org/curriculum/waterproj/)!

Your class can “adopt” a local stream. Learn the “Five Steps to Stream Adoption” at the Adopt-a-Stream Foundation Web site (http://www.streamkeeper.org/tools/steps.htm).

You can also “Adopt Your Watershed” through an Environmental Protection Agency campaign (http://www.epa.gov/adopt/). The EPA began this campaign in 1997, 25 years after enactment of the Clean Water Act, to encourage citizens and organizations to become stewards of the nation’s rivers, streams, wetlands, lakes, groundwater, and estuaries.

Adapted with permission from BELL LIVE! 1998: Aquatic Adventures, from the Bell Museum of Natural History, University of Minnesota

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