January 18 , 2005

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Classroom Activities




The student will be able to:

  1. Describe a wetland.
  2. Identify how wetland components can remove contaminants.
  3. Describe limitations to wetlands' cleaning ability.


Students simulate water moving through a wetland and wetland components that remove contaminants


  • large play area (see diagram)

  • 3 green and 3 brown ribbons or labels, either tape, stick-on labels, or pieces of cloth

  • red and blue ribbons, enough for all students to have 3 red and 6 blue

  • boundary markers

  • signs to mark the "inlet" and "outlet"of the wetland


Science, Earth Science



at least 20 students

indoor or outdoor

Wildlife and Ecological Systems
VII. Wildlife, Ecological Systems, and Responsible Human Actions

KEY VOCABULARY contaminant, fertilizer, runoff, sediment, wetland



You could think of a wetland as a passive washing machine, with its plants and soil acting as the soap. Together these elements clean up water that flows into a wetland. The first step is to slow down the water (as described in activity, "Hold the Load").

As water moves through the vegetation, sediments settle out and bacteria and other microorganisms in the wetland soil go to work, "scrubbing" out the pollutants (neutralizing them through chemical reactions). Wetland plants absorb other contaminants, using some — such as nitrogen — as nutrients.

In the Intermountain West, irrigation waters can send large amounts of fertilizer and pesticides into waterways. Wetlands can help clean up some of this contamination, but not all.

Idaho Fish and Game LogoIdaho Fish & Game Project Wild Logo


That's why state and federal government agencies are working together with the agriculture industry to reduce the use of fertilizers and pesticides, or to apply them more effectively so less run off into our waterways.

All wetlands have some sort of inlet and outlet, although these aren't always obvious. You can see the inlets and outlets for wetlands along streams, rivers, and around lakes. But bogs, playas, and other isolated wetlands have more subtle exchanges of water. Water flows in from surrounding upland, and usually remains in the wetland until the water seeps into the ground or evaporates.


1. Discuss with students how water enters a wetland and the components of a wetland.

2. Set up a large play area as a wetland: Mark its boundaries, and also its inlet and outlet.

3. Explain the roles available for this activity:

A) PLANTS of the wetland (3 students). These students wear a green ribbon and will remove fertilizer from the water.

B) SOIL of the wetland (3 students). These students wear a brown ribbon and will remove sediments and contaminants (such as metal) from the water.

C. WATER (the remaining students). Each person wears 2-3 pieces of red tape and of blue tape. (Blue tape represents fertilizer; red tape represents sediments and contaminants.) They will move through the "wetland."

4. Pick students to fulfill these roles or ask for volunteers. Make sure the students understand their roles.

5. Position the water students at the inlet of the wetland, and the plant and soil students inside the wetland.

6. Give the students these instructions:

A. The water students wait at the inlet until you give them the cue to proceed through the wetland. Then they walk through the wetland, allowing the plant and soil students to remove their ribbons.

B. The plant and soil students move among the water students, removing ribbons. They attach each ribbon to themselves.

C. When you give the cue to exit the wetland, all the water students move through the outlet.

7. Have the water students stand together so that everyone can see how many ribbons remain on them. Then discuss how many ribbons are now on the plant and soil students.

A. Compare the distribution of ribbons now to the beginning of the activity.

B. Discuss how and why the ribbons have been rearranged as they are. How does this compare to the way that a wetland really works? Why do they think wetlands behave this way?

C. Discuss how many ribbons remain on the water students. Where will the remaining contaminants go? What will happen to them?

8. Conduct this activity again, explaining that this time the wetland is downstream from a farm. Runoff from irrigation and rain carry fertilizers into the stream. Ask the water students how many more blue ribbons they should wear (double). Repeat Steps 6 and 7; in the discussion, be sure to compare the results between the two runs of the activity. In addition, ask the following:

A. Are there more contaminants leaving the wetland outlet? If yes, how would this affect the water downstream? Would it harm aquatic animals? Terrestrial animals? How might it affect humans?

B. How could these extra contaminants be controlled at the farm, in the stream, in the wetland, and after leaving the wetland?

Explore students' understanding of this activity by discussing or acting out additional alterations to a wetland, such as:

1. A developer dredges the wetland and removes all the plants.
2. A storm dumps a huge amount of water in your area.
3. You have a wetter than normal summer or a drier than normal summer.
4. A mudslide buries the wetland.
5. A fire burns the trees and vegetation of a wetland.
6. Boaters want to be able to motor through the wetland.
7. Anglers want to be able to fish in the wetland.
8. A rare plant or bird is discovered in the wetland.
9. A non-native plant is discovered in the wetland.

1. Divide the students into three small groups: water, plants, soil. Ask each group to develop a poster that illustrates a real wetland and how their component contributes to filtering out pollutants. Display the posters where other students can view them.

2. Ask the students to choose a wetland in your community. Explain that they are to investigate this wetland: discover its hydrology, its plant and animal community, and what pollutants may flow into it and out of it. They can choose the format of their investigation and report, but it should be a group effort.

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