LESSON 3	Activity 5

Grades:

4th - 12th

Objective:

Students learn interrelationships between precipitation, runoff, and wetlands. Students will relate the importance of wetland functions to their own needs and daily lives. Students will be able to discuss practical, everyday issues concerning the beneficial functions of wetlands.

Method:

Students simulate a wetland (or watch as the teacher simulates one) using a clay model, and they test the functions of the wetland by mimicking a stormwater event.

Materials:

Modeling clay, long shallow pan (9 x 13" metal or glass baking pan or a paint rolling pan) scraps of indoor-outdoor carpeting, florist's "oasis" foam or sponges, watering can or similar device, cup of soil, jar of muddy water.

Time:

Class Time: 90 minutes if students make model, 30 to 40 minutes for demonstration only.

Procedure:

Preparation:

• Spread a layer of modeling clay in half of the baking pan to represent land. Leave the other half of the pan empty to represent a lake, river, or ocean.

• Shape the clay so that it gradually slopes down to the 'water'. Smooth the clay along the sides of the pan to seal the edges. You can also form meandering streams in the clay that lead into the body of water.

• Cut a piece of carpeting to completely fill the space across the pan along the edge of the clay. This represents a wetland buffer between dry land and open water. Make sure the wetland fits well. The model won't work if there are large spaces under the wetland or between the wetland and the sides of the pan.

Intro: Review what students have learned about wetlands and their functional values. Show pictures of different types of wetlands including freshwater and salt marshes, swamps, and bogs. Have the students think about the animals and plants that might live in each kind of wetland.

Activity:

1. Present the wetland model and point out its features. Explain that wetlands, like all habitats, are very complicated natural systems. They perform very important functions such as filtering pollutants, reducing flood damage, and preventing soil erosion. Some wetlands, at times, recharge underground water supplies. Explain that the model will show this in a very simplified way. Ask students: If I make it "rain" on the model, what will happen to the rain water?

2. Fit the piece of carpeting or sponge into the wetland area, slowly sprinkle some "rain" on land, and let the students observe and describe what is happening. Some of the water is stored by the wetland (carpeting). The excess slowly flows into the body of water. Point out, if the students do not, that the wetland absorbed some of the water (pick up the wetland and squeeze some water out to prove it).

3. Ask: What do you think will happen if the wetland is removed? (The water will not be absorbed; it will flow more quickly into the body of water.) Remove the carpeting and water. Pour the same amount of water on the model at the same spot and rate as before. Have the students note any differences. The water will fill the body of water much more quickly and may eventually overflow and flood the land. That's because it is no longer buffered by the wetland.

   Explain that most wetlands are shallow basins that collect water, slow its rate of flow, and also retain water for a time. This slowing process helps reduce flooding and also helps prevent soil erosion.

   Ask: If a wetland is destroyed and houses are built there, what might happen to the houses during a severe rainstorm? Why? (They might be flooded because the wetland will not be there to absorb and slow the rush of water from higher ground.) In many areas, wetlands are drained and filled in, and houses are built right along the water. Without a wetland buffer, these developed areas, particularly in flood plains, are subjected to severe flooding and erosion, especially during violent storms.

4. Pour the water from the last demonstration out of the model and put back the carpeting. Explain that this demonstration will be just like the first, except that soil will cover the clay. Ask: What do you think will happen to the bare soil when it rains? (The rain should pick up and carry some sediment over the land and into the body of water.)

5. Spread soil over the clay and make it rain, or pour muddy water from the jar over the soil. Explain that this water represents pollution runoff. Ask the students to compare the water that ends up in the body of water with the water in the jar. Explain that the soil particles were trapped by the carpeting, making the water in the body of water much clearer. The "uphill" side of the wetland should be coated with trapped sediment.

6. Remove the carpeting, pour out the water, and try the experiment again. What happens without the wetland in place? Ask the kids why all the dirt particles end up in the body of water this time. The thick mat of plant roots in a wetland help trap silt and some types of pollutants much as the carpet did in the model. Without a wetland, excessive amounts of silt and pollutants can end up in lakes, rivers, and other bodies of water.

7. Ask students:

   • How might muddy water affect fish? (Makes it harder for them to see, irritates their gills so they can't breathe easily, and could lead to their death.)
     

   • How might other animals and plants be affected by the muddy water? (Sediment smothers oysters; plants do not get enough sunlight; birds and other animals may have trouble seeing food in the muddy water, or food sources may die; etc.)
     
   • How might boats and ships be affected by muddy water? (The mud settles out and sediment eventually fills channels needed for navigation.)
     
   • How might drinking water supplies be affected by muddy water? (The mud settles out and eventually fills in water supply reservoirs. Sediment particles can also harbor bacteria or other pathogens.)
     
   • How might you be affected? (Loss of natural resources and food sources; decline in quality of drinking water; loss of recreational activities such as swimming and fishing.)
     
   • How can we prevent these undesirable effects? (We can protect wetlands and help make their benefits known!)
     

Extension:

Students, individually or as small groups, can make their own, more detailed wetland models using small aluminum foil pans, clay, and florist's foam. Then students can draw plants and animals and attach them to the model with toothpicks. Students can use an assortment of materials, including natural ones they collect, to decorate their models. They can make a freshwater or salt marsh, freshwater or mangrove swamp, or bog. Provide reference books with pictures of different types of wetlands.

Note: Another activity dedicated to wetlands, A Walk Upstream (by Mohonk Preserve) is a useful activity that will allow students to identify what kinds of things they may find in a wetland, and how wetlands function.

Assessment:

1. How do wetlands function to reduce flooding and retain sediments?

2. What would happen to water, sediment, homes, and wildlife if wetlands were destroyed?
   

NYS Learning Standards:

Arts
Standard 1 - Creating, Performing, and Participating in the Arts: Visual Arts

Math, Science, and Technology
Standard 1 - Analysis, Inquiry, and Design: Scientific Inquiry 1
Standard 4 - Science: Physical Setting 2; The Living Environment 7
Standard 5 - Technology: Tools, Resources, and Technological Processes
Standard 6 - Interconnectedness: Models
Standard 7 - Interdisciplinary Problem Solving: Connections

Source: This activity was adapted with permission from the activity "Wetland in a Pan," published in WOW!: The Wonders of Wetlands, 1995. Published by Environmental Concern Inc., St. Michaels, MD, (410) 745-9620, and The Watercourse, Bozeman, MT, (506) 994-1917.