Lesson Description:
Many students may already be aware that wetlands serve as homes for scores of birds, fish, and other wildlife. But wetlands’ other environmental values may be lesser known. How many students are aware that wetlands slowly filter out pollutants that dissolve into runoff from pavement, pesticide-treated farmlands, and other sources? If untreated, harmful chemicals from runoff (such as lead, chromium, and mercury) can enter streams, rivers, and groundwater. But when water filters through a marsh, many impurities settle to the bottom. Thus, the discharge that exits the wetland is often cleaner then water that entered it.

Over time, however, the volume of pollution entering marshes can overwhelm natural wetlands. the water can become toxic to fish, birds, and other aquatic creatures. The grasses and other plants in the wetlands begin to die off as their leaves and roots react to the pollution. The contaminants can be dredged out, but at the cost of impacting the wetland and destroying valuable habitat.

But there is a way to harness the pollution-removal quality of wetlands while minimizing impacts to natural habitat. Engineers create specially designed stormwater wetlands to treat runoff from housing developments, industrial complexes, and parking lots. These artificial marshes can be designed to look and function like a natural wetland. Stormwater wetlands remove pollution while providing additional habitat for fish, birds, and other water-loving creatures. and best of all, when the bottom of the stormwater wetland fills with pollution (after about 15 to 25 years), the artificial marsh can be drained, dredged, and then reconstructed.

In this project, your students will build their own model stormwater wetland and conduct experiments to see how this fascinating water-cleaning process works.

http://www.thirteen.org/edonline/wue/water3_overview.html

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Lesson Type:

• Experiment
• Project

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Sustainability Topic:

• Ecosystems
• Water

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GEF Program Category:

• Sustainable Water Challenge

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Standards Addressed:
North American Association for Environmental Education (NAAEE)
Excellence in Environmental Education: Guidelines for Learning

• Strand 1: Questioning and Analysis Skills (Guidelines a, b, c, d, e, g)
• Strand 2.2: The Living Environment (a, c, d)
• Strand 2.3: Humans and Their Societies  (c, e)
• Strand 2.4: Environment and Society (a, b)
• Strand 3.1: Skills for Analyzing and Investigating Environmental Issues (a, b, c, d)
• Strand 3.2: Decision-making and Citizenship Skills (a, b, c, d)
• Strand 4: Personal and Civic Responsibility (b, c).

Technology Foundation Standards for Students

• Standard 1: Basic Operations and Concepts
• Standard 3: Technology Productivity Tools
• Standard 4: Technology Communications Tools
• Standard 5: Technology Research Tools

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