Click here to Return to Culutres and CyclesClick here to Return to Science

Beyond the Tap
Original lesson by
BELL LIVE! 1998: Aquatic Adventures, from the Bell Museum of Natural History, University of Minnesota
Modified and adapted by
Karen Munroe & Rachel Hughes
Edited By Stephanie Nardei, MLS
Click here for Print Lesson
Click here for Lesson Feedback

Time: 4 class periods
Prep Time: 1 hour
Materials: Relief and topographical maps of your local area where watersheds are evident.
Topographic Maps on Wikipedia
Bucket, some 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, 1 sprinkling can or spray bottle per group and internet access.


Watersheds are complex, multifaceted systems that serve a variety of needs for humans, plants, animals, and invertebrates including providing fresh clean drinking water and habitats. Humans can and do have numerous effects on watersheds by changing water flow patterns and introducing pollution. Through discussion and creation of a model watershed, students will understand how watersheds function. Students will also explore their local sources for water by reviewing local watersheds using a variety of maps and learn about the importance of watersheds and the impacts humans have on them.

Students will:
1. Explain the basic properties of a watershed including how water flows from higher to lower elevations and how watersheds are interconnected.
2. Understand how the placement of buildings, roads and parking lots can be important to watershed runoff.
3. Understand how careless use and disposal of harmful contaminants can have a serious effect on downstream watersheds and their inhabitants.

National Science Education Standards
Content Standard D
Earth and Space Science
In grades 9-12, students review the water cycle as a carrier of material, and deepen their understanding of this key cycle to see that it is also an important agent for energy transfer.

Teacher Background
EA watershed is an area of land that catches precipitation that drains or seeps into a marsh, stream, river, lake or groundwater. Watersheds are habitats for living things, such as plants, animals, fish, waterfowl, aquatic insects, and invertebrates.

The runoff of small watersheds joins together and their combined areas become a new, larger watershed. Large watersheds, such as the Mississippi Basin and the Chesapeake Bay drain into large bodies of water, and cover immense land areas. Despite their differences in sizes, all watersheds share common properties. They all perform the same function of transporting water over the earth’s surface. The watersheds encompass suburban lawns, parking lots and city streets. Water seeps down through the soil to aquifers, which are underground formations in rocks and soils that contain enough groundwater to supply wells and springs.

It is clear that humans have a close relationship with watersheds. We have built reservoirs for water supplies, hydropower and recreation, straightened and channeled streams for flood protection, developed towns and cities along primary waterways, routed water to irrigate dry farmlands, fertilize agricultural crop fields and also inadvertently fertilize harmful microorganisms in rivers and lakes through runoff and improperly disposed of household and industrial chemicals into watersheds. As a result, watersheds have experienced a degradation of water quality, reduction of streamside vegetation and a general degradation of aquatic and riparian ecosystems.

Watersheds can also have an effect on humans. Floods are one of the major events in a watershed. Homes built on flood plains, low lying areas adjacent to rivers, are susceptible to flooding conditions when heavy precipitation exceeds the watershed’s capacity to absorb water. Rivers, streams, and lakes overflow, threaten human lives, and damage or destroy roads, buildings, and flood control measures. Watersheds can also become dry, causing water shortages for those who depend on their lakes and rivers for drinking water. Water treatment prepares this water for human consumption, but if the water is laden with chemicals and microorganisms, it can be difficult to treat effectively.

Watersheds can be complex, multifaceted systems that serve a variety of needs for thousands of people. Watersheds also cross political boundaries; therefore the people who manage them must take a broad swath of economic, political, industrial, ecological, and cultural variables into consideration. Clean, fresh water is essential 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.

Related and Resource Websites
EPA Build Your Own Watershed

National Geographic on Conservation & Watersheds http://www.nationalgeographic.com/gaw/frwater/frwater_912_teacher.html
City of Tucson 2006 Water Harvesting Guide Adobe Icon

Drainage Basin on Wikipedia http://en.wikipedia.org/wiki/Drainage_basin

Image of a Water Shed


Days 1- 2
1. Have a large topographic or relief map of your local area placed in a position so that students are able to easily see it. If possible, have a map for each group of four students. Having aerial maps of your area that show watersheds would also be powerful. Google Earth, among other online programs, makes these easily available. As students come in ask them to look over the maps and aerial photographs and in pairs come up with a definition of the term ‘watershed’ using examples or descriptions from their local area. Ask them to write this down before sharing as a class. Students should be familiar with the term, but focusing them on watersheds in relation to their own environment may help to solidify this concept. Lead a discussion about how people have used and changed watersheds. Explain that students will be creating their own watersheds and exploring their local watershed(s).

2. 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 are formed. Assist students as they build and experiment with their models.

3. 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 with lumpy mashed potatoes, and then shoved half the potatoes to one end to form a lumpy mountain.

4. 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.

5. 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.

6. Your watershed looks like a nice place to live. Why not build some houses there? Team members should switch tasks again. Place two foam peanuts (your “houses”) on flat locations in the watershed. The “rainmaking” student should rapidly spray water on the upper portion of the watershed. Observe the houses. Explain that rapidly spraying a large amount of water creates a flood in the watershed. Observe the houses during the “rainstorm.” Did the flood cause different amounts of damage to the houses (such as causing them to move) based on their location 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?

Days 3- 4
1. Go to the website: http://cfpub.epa.gov/surf/county.cfm?fips_code=04019. This website has generalized maps for all 14 watersheds located in Pima county.

2. Have students locate their local watershed(s) and any associated watersheds, particularly those downstream.

3. The United States Geological Survey is currently researching the Upper Santa Cruz watershed (which encompasses the city of Tucson; http://minerals.cr.usgs.gov/projects/santacruz/index.htm). However there is substantial information on the San Pedro watershed, which is east of Tucson. Use the following website to help answer the following questions: http://www.srnr.arizona.edu/nemo/index.php?page=characterization

a. What are the major rivers, streams, creeks and lakes? Draw and label these on your map.
b. Where does the watershed begin and end? Label these on your map.
c. What types of geology exist in this watershed? Describe the geology.
d. What possible sources of contamination and pollution exist in this watershed (i.e. cities, mine sites)? Label these on your map.

1. Arrange a field trip to the community’s water treatment facilities.

2. While students are making their model watersheds, you can encourage them to identify first-order tributaries, second-order tributaries and have them research stream shapes and drainage patterns. Ask them to try to create models that simulate the different patterns.

3. Have students download clip art of aquatic flora and fauna at the Environmental Protection Agency site (http://www.mnsinc.com/eightbal/watershed/outreach/activitypixnonjs.html) and use it to illustrate the impact watersheds have on our environment. The art and icons at this site would be useful if you have your students create displays or make posters for Geography Awareness Week. Students could create bookmarks and hand them out during the week or at a science or geography fair.

4. Have students write a short essay discussing what they learned about watersheds and floods. As part of the essay, have them draw a picture of a watershed, including a stream and associated floodplains. Students should also write about the best place to build homes to avoid flooding within their watershed.

Embedded Assessment

Students demonstrate their ability to identify and describe watersheds with a labeled map of a local watershed, which includes potential sources of pollution and contamination. The discussion at the beginning of the lesson serves as a way to assess prior knowledge.

PULSE is a project of the Community Outreach and Education Program of the Southwest Environmental Health Sciences Center and is funded by:

NIH/NCRR award #16260-01A1
The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award


Supported by NIEHS grant # ES06694

1996-2007, The University of Arizona
Last update: November 10, 2009
  Page Content: Rachel Hughes
Web Master: Travis Biazo