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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.
PROCEDURE
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?
EVALUATION
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.
EXTENSIONS
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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