Procedure:

1. Ask students to list the characteristics of a wetland. Record their answers on the chart paper or overhead. Ask them to respond when asked the question, "Which of these characteristics might apply to all wetlands?"
2. Show the students the overhead map of the major wetland areas of the United States.
3. Have the students color the major wetland areas using the map key.
4. Pass out the information sheets for the students to read. (For younger students, read the information or read a picture book about wetlands.)
5. Students answer questions in a small group.
6. Demonstrate making the model of a wetland:

1. Spread a layer of modeling clay in half of the roasting pan to represent land.
2. Shape the clay so that it gradually slopes down to the body of water.
3. Smooth the clay along the sides of the pan to seal the edges. You can also form meandering streams in the clay that led into the body of the water.
4. Cut a piece of indoor-outdoor carpeting to completely fill the space cross the pan along the edge of the clay. The carpeting represents the wetland buffer between dry land and open water.

7. Have the students build their own wetland model.
8. Give them a lab sheet to record the results of the functions of a wetland. Then have them perform the following activities:

1. Flood control - pour some of the water (be sure to save some) slowly on the land and describe what happens.
2. Water purification - pour the water out of the model again and replace the carpeting. Pour some of the muddy water onto the land. Ask the students to note and compare the water in the jar and the water in the model. Now remove the carpeting and repeat using the same amount of water, noting the differences.

9. Discuss the experiment with the students and discuss the other important functions of wetlands, such as habitat for wildlife and recreation sites.

Extensions:

Students can make models of various types of wetlands, substituting florists' foam for carpeting so they can poke in wildlife and vegetation models for decoration. Provide them with resources to see examples of the various types of wetlands. Visit a wetland and make tests and observations.

The water's up to your ankles and a pungent smell reaches your nose. You move along slowly, watching a great blue heron fish for its lunch. When you round a bend, you're startled by a flock of ducks as they take off from the water. A dragonfly zips past your head as you watch the ducks fly up over the trees.*****You could be in a swamp or a salt marsh or any of a number of different types of wetlands. In this chapter we'll discuss just what we mean by the word wetland- and we'll look t what makes these soggy habitats so special.

It's hard to find a lot of absolute characteristics that apply to all wetlands. That's because there are so many different kinds of bogs, marshes, swamps, and other wetlands. (For descriptions of many of the different kinds of wetlands, see the background information on pages 18-20 and 33-35.) But all wetlands share some characteristics that set them apart from other kinds of habitats.

What They Are and What They Aren't: Of course, all wetlands are wet- but so are ponds, lakes, streams, rivers, and oceans. Does that mean, then, that these particular bodies of water are wetlands too?

In general, no. Most scientists who study wetlands restrict their definition of these habitats to areas that, at least periodically, have waterlogged soils or are covered with a relatively shallow layer of water. These areas support plants and animals that are adapted to living in a watery environment. (For more about the plants and animals that live in different kinds of wetlands, see Chapters 2 and 3).

Soggy Surroundings: The reason that wetlands are wet varies. Since most wetlands are located in low-lying areas, rain and runoff help to keep the area saturated. Also, some wetlands lie in places where the groundwater is at or very near the surface of the ground, which means that they're constantly being "fed" from below. Other wetlands stay wet because they're next to rivers or other bodies of water that regularly overflow their boundaries. And along the coast, the tides keep many other wetlands saturated

Beavers and Other Builders: Some wetlands get started with a little "outside" help. Beavers, for example, are important wetland builders. The rivers and streams that they dam often flood large areas, turning meadows into marshes and parts of the forest into swampland.

People sometimes create wetlands too- both intentionally and unintentionally. For example, a state game and fish agency might flood an area so that waterfowl will have more places to breed. On the other hand, a swamp or marsh might get its start accidentally when construction blocks the natural flow of water and causes a stream to back up and overflow.

Wetlands give the world a lot of "free services." Here's a look at some of the important functions they perform.

*Flood Busters: An easy and cheap way of controlling floods is to leave wetlands in their natural state. That's because wetlands act like giant, shallow bowls. Water flowing into these "bowls" naturally loses velocity as it collects and spreads out. Wetland vegetation helps to slow down fast-moving water too. As a result, flood damage to developed areas near wetlands is often much less than damage to areas located near wetlands that have been drained and filled.

Silt Trappers: When flood waters are slowed by wetlands, the silt and other sediments they carry settle out among the roots and stems of wetland plants. This helps to protect streams, lakes, and other bodies of water downstream from a build-up of sediment that could otherwise clog aquatic animals' gills and bury their eggs. It also helps protect water supplies from pollutants and other impurities. That's because wetland plants can take up and use nutrients and chemicals that the silt may contain. If it weren't for wetlands, these impurities might eventually contaminate rivers, lakes, groundwater, and other water supplies-some of which are used as sources of drinking water. (For more about how wetlands can offset the effects of pollution, see "Don't Touch That Wetland" on page 48.)

Storm Breakers: Farms, forest, and buildings that are located behind wetlands along the seashore and large lakes often fare much better during storms than those that aren't. Wetlands serve as buffers between the winds and waves of storms and the areas beyond. But "taking the punishment" isn't all wetlands do during storms. They also bind soil and help to keep it from eroding. Mangrove swamps are particularly good at this. In fact, certain islands cleared of their mangrove swamps have become so severely eroded that they're no longer visible above the ocean's surface. (For more about mangrove swamps, see the background information on page 20.)

Acre for acre, there's more life in a healthy wetland than there is in almost any other kind of habitat. These productive places can support huge numbers of insects, fish, birds, and other animals. Below is a rundown of some of the ways wildlife uses wetlands.

Migration Vacations: If you visited a wetland in fall or spring, chances are you'd see many kinds of migrant birds. And depending on exactly where you were, you could see hundreds or even thousands of them: ducks and geese, herons and egrets, sandpipers and plovers; maybe even eagles and ospreys. These and other birds converge on wetlands en route to their winter or summer homes. Here they "refuel" on the rich food supply before getting on with their journeys. (Many birds’ nest and winter in wetland too- but the bird population of most wetlands goes way up during migration.)

Natural Nurseries: There’s another segment of wetland society for which wetlands are vitally important temporary homes. These are the young of certain fish, crabs, and other creatures that spend their earliest days in wetlands before moving on to open waters. The thick vegetation of a wetland is a good place to hide, and the rich food supply gets growing animals off to a healthy start.

Havens for Rare Ones: Wood storks, snail kites, whooping cranes, and American crocodiles are all endangered species-and they all live in wetlands. In fact, about 35 percent of all the animals and plants listed as threatened or endangered in the United States either live in wetlands or depend on them in some way. That means that more than a third of the nation's rare animals and plants are inseparably linked to areas that, altogether, make up only about five percent of the total land area in the lower 48 states. This fact doesn't seem to leave room for much optimism-especially since wetlands are still being dredged, drained, and filled in for farms, houses, and other developments. But wetlands are getting some protection.

To find out more about how people are helping to preserve wetlands, see "Taking Care of Wetlands" on page 48.

The New York State Freshwater Wetlands Act defines "freshwater wetlands" as lands and waters of the state which support aquatic or semi-aquatic vegetation of the following types:

1. Wetland Trees
2. Wetland Shrubs.
3 Emergent Vegetation
4. Rooted, Floating-leaved Vegetation
5. Free-floating
6. Wet Meadow
7. Bog Mat Vegetation
8. Submergent Vegetation

The nature of a wetland site, including the amount of water present, determines the type of vegetation found. All types of wetland vegetation grow either in the water or in places where the water table, i.e. the level beneath which the soil is saturated with water, is relatively near the surface. The roots of wetland trees, for example, have to extend down only a short distance below the soil surface to find ground water.

The Typical Marsh Cross Section (Figure l) and the Typical Bog Cross Section (Figure 2) show where the various types of vegetation are commonly located. In the marsh, water milfoil is representative of plants that grow underwater. Bulrushes are emergent plants; the roots are anchored in soil beneath the shallow water and the rest of the plant grows up into the air. Sedges are found in wet meadow areas and may reach a height of 4 feet. Alder, a wetland shrub, grows to approximately 15 feet while mature red maples grow taller.

The bog cross section shows that wetland trees and shrubs grow where the water table is near the surface. It also depicts the bog mat plants cranberry and leatherleaf growing on a floating mat composed primarily of an accumulation of dead sphagnum moss, called peat.