TEACHERHANDOUTWATERSHEDWISDOM

Funding and support for the All About Watersheds Lesson provided by

EXPLORE BENEATH THE SURFACE Summary: In this activity, students will explore the movement of water across pervious and impervious surfaces and consider the function of soil in a watershed. Learning Objectives: After this activity, students will be able to:

- Define and provide examples of pervious and impervious surfaces. - Explain how pervious and impervious surfaces impact watershed health. - Describe the function and purpose of rain gardens and the ways in which healthy plants and

animals support watershed health.

Materials Needed: - Five clear plastic cups (that students can easily see through), approx. 8 oz. each - 8 oz. gravel/stones - 8 oz. garden soil - 8 oz. clay soil (or mulch if clay soil is inaccessible) - 8 oz. sand - Aluminum foil or plastic wrap - Rubber band - A cup, pitcher, or watering can filled with water

Procedure: Teacher Narrative: “Today we are going to investigate the different types of land that make up a watershed. When we made our crumpled paper watersheds, we learned that rainwater takes a journey from its cloud to the ocean, passing through different kinds of land, traveling across diverse surfaces, and joining a few bodies of water before it reaches its destination. Now, we will explore what happens to water beneath the surface of five types of land.”

1. Place 5 plastic cups side-by-side in a place where students can circle around and see them. 4 should be filled with gravel/stones, garden soil, clay soil, and sand (one material per cup). The 5th should be empty but covered with aluminum foil or plastic wrap secured by a rubber band.

2. Predict. Ask students to think/write/talk about their predictions regarding how water will soak into each surface. What will happen in each cup during a “rainstorm”? What will happen after the rainstorm has ended? In what ways will each cup be different? Will any cups have similarities? What kind of land might the foil/plastic wrap represent? What kind of land might the packed clay soil represent?

TEACHERHANDOUTWATERSHEDWISDOM

Funding and support for the All About Watersheds Lesson provided by

3. After students reach their hypotheses, create a rainstorm using a pitcher, cup, or watering can

filled with water. Pour the same amount of water into each cup, one at a time, pausing for a moment to have students observe, discuss, and/or take notes about what happens to the water when it interacts with the contents.

4. Reflect & Discuss. Were students’ hypotheses correct? Why or why not? What were students surprised by? What challenged their thinking? What does this activity teach us about land in our watershed? What kind of land does water move across easily? On what kind of land does water get “stuck”?

5. Introduce the terms “impervious surface” and “pervious surface” to students:

Impervious Surface: Land or another surface that does not allow water to soak into it (ex: pavement, brick, concrete sidewalks, etc.). Connect this term to students’ initial predictions about what the foil/plastic wrap might represent. Pervious Surface: Land or another surface that does allow water to soak into it.

Ask students to imagine some of the benefits and disadvantages of using pervious vs. impervious materials in our landscape. Guide students toward the understanding that impervious surfaces facilitate water pollution (ask: “What might water ‘pick up’ on its path across impervious surfaces?”), whereas pervious surfaces act like filters, removing toxins like fertilizers and insecticides, oil, trash, etc.

6. Vote. Raise each cup, one at a time, and ask for a show of hands as to whether students would like to label its contents “pervious” or “impervious” (hint: all materials should be pervious except for the plastic wrap/foil)

7. Circulate printed pictures/articles about rain gardens in North Carolina (see final page of this activity for links to examples).

Optional Technology Integration: Ask students to research rain gardens in North Carolina, individually or in teams, and present their findings to the class.

8. Discuss: What are rain gardens? What purpose do they serve? What are they made of? Who

makes them? Where can they be found? Based on your observations during the activity, what do you think are the best kinds of materials to use in a rain garden? Helpful Hints: Rain gardens are planted shallow depressions that capture and soak in rainwater before it enters

TEACHERHANDOUTWATERSHEDWISDOM

Funding and support for the All About Watersheds Lesson provided by

a water way or a storm drain. Just like sliding down a waterslide and splashing into a pool, so will rainwater travel into the garden, which is filled with shrubs, perennial plants, and grasses that can withstand dry conditions and don’t mind having “wet feet,” as many rain gardeners say, meaning a very wet root system. They will trap and filter rain water, clearing 90% of chemicals and 80% of sediment (www.groundwater.org), draining within one to two days and absorbing 30% more than a traditional grassy lawn. Rain gardens improve the health of the watershed ecosystem by attracting bees, butterflies, birds, and other animals. And they improve our health, too, by cleaning—not only the water that funnels into rivers, lakes, and the ocean—but the water that travels to aquifers, where we obtain drinking water (www.watereducation.org). Rain gardens mimic a natural or undisturbed vegetated ecosystem like a forest or a prairie. Clay soil infiltrates very slowly, and when packed by construction vehicles during development it becomes close to impervious, so lawns may be close to impervious, and therefore do not have the same “filtering” effect as rain gardens. Example Articles and Pictures of Rain Gardens in NC: Durham, NC Rain Gardens https://durhamnc.gov/787/Rain-Gardens NC Backyard Rain Garden Design http://www.ncagr.gov/SWC/costshareprograms/CCAP/documents/Chapter5-BackyardRainGardenDesign.pdf NC State University Rain Garden Manual https://www.townofchapelhill.org/home/showdocument?id=17409 NC Coastal Fed https://www.nccoast.org/project/school-rain-gardens/

9. Using students’ knowledge of their school grounds, ask them to consider the best placement of a rain garden at school. Are there grassy areas that water travels across on its way downhill? Where have you noticed water after a rainstorm? How does water move across our playground? Are there areas that would look more pleasant with shrubs and flowers? Optional Extension Activity: Use printed maps or diagrams of your school grounds during this activity. Have students draw the placement of their rain garden on the map and write one or two sentences describing their reasoning for that placement. Optional Technology Integration: Invite students to research, individually or in teams, plants in their region that can withstand “wet feet.” What plants would be best suited for a school-ground rain garden, and why? Have each student or team research 2-3 plants and present their findings to the class.