Introduce the concept of a bay and its watershed by showing students the Xpeditions interactive
Satellite Spy Glass, which allows you to zoom in to the Chesapeake Bay area. (Note: The telescope will ultimately zoom in to an image of Washington, DC.) Begin by explaining to students that they are looking at the Earth through a special telescope mounted on the space station. Ask students to identify all physical features that they recognize (answers should include such responses as continents, countries, islands, bodies of water, etc.). Explain that as you zoom in with the telescope, they will be able to see more detail and recognize more features. Begin to zoom, and continue having students identify the physical features found in the image.
As you zoom, draw attention to the Chesapeake Bay. Explain to students that the image shows a bay, and have them identify some characteristics of the bay. Then, collectively define the term bay based on their observations (an inlet of a larger body of water that is partially surrounded by land). Continue to zoom in. Ask the students if there are any other bodies of water near the bay (rivers, tributaries, etc.). Explain to the students that these rivers and streams "feed" the bay and that the water found in them will eventually reach the bay. Ask the students where they think the water in the rivers comes from (rain, run-off, smaller streams). Explain that much of the rain that falls will eventually find its way to a stream, then a river, and ultimately to the bay. When the telescope focuses on Washington, DC, ask students if they are familiar with the place the telescope is zooming in on.
Then, have students explore the Chesapeake Bay watershed by having them visit the Chesapeake Bay Program’s watershed map. Explain to students that a watershed is the total land area from which a river system collects its water. Ask students to name the states that are part of the watershed. Direct them to a glossary if necessary. Then have students explore the slide shows available at the Chesapeake Bay Program's photo gallery.
Activity 1: A Model Watershed
Explain to students that to really understand how water raining on land can end up in a bay, they will create a watershed model. Create the model by shaping foil or other molding material, which represents land, within a large, shallow pan (metal or plastic). It should be molded so that some parts are flat while other parts have bumps and uneven parts. The foil/clay should slope downward so that there is an area at the end of the pan where water can collect. Have students take turns creating rain by gently pouring a small amount of water near the upper slope of the land. Have students watch the water make its way through the land and collect at the bottom to show how groundwater seeps down to the lowest level. If necessary, the slope of the pan can be increased by placing a book under the upper end of the pan. Demonstrate and explain to students that this is what happens in a watershed—the land is shedding the water. (Note: Keep this model intact for use later in the lesson.)
Activity 2: The Chesapeake Ecosystem
Use the Bay at a Glance picture on the Chesapeake Bay Program Web site to point out the connections between the bay and its watershed and the people, plants, and animals that live on them. Explain to the students that many people, animals, and plants call the bay their home. Remind them that each of their actions may affect life for the others who share the bay.
Have students play the Concentration Game on the EPA's site. In this game, students match pictures of "critters" to learn about life in and around the bay. After successfully matching the cards, each animal or plant featured is described below the cards on the same page. Have students use the Chesapeake Bay Program site to choose one animal or plant to write about. Have each student choose a different animal and tell the students that they will each make a page for a class book about critters and plants in and around the bay. Each child's page should feature the name of the animal or plant, a drawing using color, and three facts about it. You can compile the pages into a class book.
Students should share their pages with the class, explaining the animal or plant featured on their page. After sharing, the teacher should ask students who else lives in the Chesapeake Bay watershed. Students should respond that people do.
Activity 3: What Impact Do Humans Have on the Health of the Chesapeake Bay and Its Watershed?
Using the watershed model previously created, have students consider what happens when something bad gets into the water. If your students are not yet familiar with the word pollution, explain that it is chemicals or other usually man-made materials which spoil the environment. Ask students what would happen if some kind of pollutant got onto the land. Discuss how this might happen (keep it simple: oil leaking from a car, for instance). Tell them the food-coloring represents pollution. Place a few drops of food coloring on one spot on the "land" and ask students to guess what will happen if it rains again. Have a student pour water again so that students can watch the flow. Explain that this is called runoff (or the water that flows off of land into a body of water and may carry pollutants with it), and point out that the liquid may flow all the way to the body of water at the bottom. Ask them what they think this means happens to the pollution from all the places along the watershed, such as from the city of Washington, DC.
Again, using the Satellite Spy Glass interactive, focus students' attention on the image of Washington, DC. Point out the Potomac River on the southwest side of the city. Have students look at the image of the city, and ask them what might happen if it rained in the city and the water "cleaned the streets" and then ran into the river (pollutants would run into the river). Then, start to zoom out from the city while having the students track the progression of the pollutants from the city to the bay. Ask them to describe what effects there would be if pollution from the city ran into the bay.
Use the Bay at a Glance picture on the Chesapeake Bay Program Web site to remind students of all the living things that rely on the bay. Ask students what they think will happen to all those living things when pollution enters the water. Help students realize that because all animals, plants, and people living in the bay share its resources, pollution entering the bay will likely affect all of them. Ask students to describe what would happen if a certain type of pollutant, which kills a certain kind of fish, entered the bay. Who would be affected? Explain that even though the fish would be directly affected, the people or animals who eat the fish would also be affected.
Explain that while people share the bay, they have also affected its health over time. Have students explore National Geographic's Exploring the Chesapeake: Then and Now site and follow the "now" map tour to find examples of animals and plants that are found in the Chesapeake Bay watershed. Then, have students identify ways in which those plants and animals have been affected by changes to the environment, as well as what could be causing those changes. Answers should include the following:
- (Stop #1) Marine grasses are affected by pollutants running to the Susquehanna River (which secondarily affect migrating waterfowl).
- (Stop #3) Powerboats are polluting the bay and affecting wildlife there.
- (Stop #5) Agricultural run-off is creating algae blooms which creates "dead zones" in the bay.
- (Stop #9) Urban sprawl in Richmond is polluting the James River.
- (Stop #11) Norfolk, while trying to create bird habitats, reestablish wetlands and provide forest buffers, still hosts the "Ghost Fleet" of rusting ships which pollutes the bay.
- (Stop #12) Pollution around Smith Island has affected the sea grasses, which affects the blue crab.
- (Stop #15) Oysters are affected by the low salt concentration of the bay.
Allow students to share their answers in group discussion, and point out that science and geography are important in identifying, understanding, and managing these issues.
Activity 4: Sources of Pollution
Ask students to describe some of the activities in which people in the Chesapeake Bay watershed might participate that can hurt the bay (creating pollutants, overbuilding, recreational activities, etc.). As a prompt, you could use the Bay at a Glance picture, this time pointing out the factory and farm in the background. Describe how each of the activities they list would negatively affect the bay.
Ask students to describe ways in which people use the bay (boating, fishing, swimming, etc.) and how people may affect the health of the bay. Also, discuss how students know if they are sick—what signs do they look for? Ask students how scientists know whether the bay is sick. What might be a sign that the bay’s health is poor? Ask students to define "pollution" and to name types or examples of pollution they have seen or know about.
To illustrate human impact on the bay (or other body of water), complete the "Who Polluted the Potomac?" activity on the Population Education site. This interactive story can easily be adapted for studying the Chesapeake Bay or any other body of water. The teacher tells a story and each student plays a role in the story, adding the contents of a container (previously filled by the teacher) to the water, which represents river water. This activity connects science with social studies, as students explore how our local waters are affected by growing population and our behaviors. This activity requires advance preparation by the teacher to fill small canisters/vials with items to simulate pollutants (example: vegetable oil can be used to represent motor oil, flour or salt to simulate fertilizer, etc.).
Following the story, make a list of all of the ways in which the bay was affected, such as plastic wrappers entering the water from a beach party, detergent washing into the bay from storm drains, etc. Then have students write a summary of what happened to the river/bay and how people's actions could impact the health of the bay.
Presentations should reflect an understanding of the role storm drains play in the health of local waters and, ultimately, the entire watershed.
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