Duration: 30 – 40 minutes
Vocabulary: watershed, Chesapeake Bay, pollution
Summary: Students create a min-watershed by crumpling up paper, drawing towns, and then watching where the marker runs-off when water is sprayed on the drawing.
Objectives: Students will gain a deeper understanding of what a watershed is, where water goes when it rains, and how the things we do might affect rivers, wetlands, and other parts of our watershed.
Materials: thick paper, blue and green permanent markers, other color water-based markers, spray bottles filled with water
A watershed is defined as an area where all of the water (whether it is from rain, snow, or peoples’ sprinklers) all drains into the same area. Think of it as a funnel—all of the water on the sides of the funnel goes downhill into the same place because of gravity. Watersheds are the same! Watersheds can occur on different scales, though. For example, someone might live in the Penns Creek watershed, where all of the water in that area drains into Penns Creek, but that person is also in the Chesapeake Bay watershed, because the water in Penns Creek goes to the Chesapeake Bay. The Chesapeake Bay is the biggest watershed we belong to—this basin includes six states (Pennsylvania, New York, Delaware, Maryland, West Virginia, Virginia) and has over 150 rivers draining into it.
The things we do in our houses and towns matter because when it rains all of the chemicals, litter, or loose soil we leave behind gets washed into our streams. This can affect us on a local level, because our own drinking water or fishing spots might get ruined. This also affects people on a larger level, because we share the same watershed with all of the other people living in six states. Things that wash into our local creeks eventually wash into bigger rivers out to the Chesapeake Bay and finally to the Atlantic Ocean! For this reason it is very important that we take good care of our local streams and watersheds.
Pollution can be thought of like a dye—chemicals left behind in fertilizers, for example, start in one place, but when it rains they are carried into streams. We can’t always see it, but the chemicals spread out there like food coloring does in water, polluting many different areas.
Ask students if they know what watershed they belong to. Then, ask them for names of their local creeks. Ask them to explain why it is important for them to take care of these creeks and rivers. What would happen to the ocean if all of the little streams were polluted?
Have students work in groups of 2 or 3. Hand out supplies, and instruct students to crumple up their paper. Then, have them uncrumple it—the creases that stand up will be like hills, mountains, and ridges, and the lower areas will be the valleys. Have students trace the ridge tops with green permanent markers, and draw where they think the water would go (between the ridges in the valleys) with blue permanent markers. Next, have students “build” a town by drawing houses, farms, amusement parks, their school, golf courses, etc. on the model with water-based markers. They can design a new town or draw their own.
Once each group has its town drawn, have students describe places in their town that might produce pollution. For example, the factories and farms might use chemicals or fertilizers, or cars could leak oil onto roads. Next, explain to students that now it is going to rain. Pass out spray bottles and instruct students to spray the models. Have them watch where the water goes and see if their predictions are right. Have them also watch what happens to their town—the colors running off represents the pollution from these areas.
Have students discuss in their groups what happened to the water and if it seems like water that is healthy to drink. Where will this water go eventually? Have them brainstorm ways that they could try to reduce the amount of pollution in their town.
Ask students to explain what a watershed is.
Ask students what happens to all of the chemicals, litter, etc., humans have spread around when it rains. Ask students where water goes, and why the things we do in one place can affect people in another.
Ask students to name some of the main sources of pollution they noticed in their town.
Have students make posters informing people that we all share a watershed, or informing people of ways they can reduce pollution.
Have students go out just after a rainstorm and see how water is moving across school grounds.