Grade Levels

4 - 9

Objectives

    Students will investigate interrelationships between flowing water and topography within a watershed by:

• interpreting and using    maps of the area;
• modeling    a watershed
• comparing    modeled and actual events;
• predicting    path of runoff;
• communicating    water quality information.

Standards of Learning

Science:

• Grade Four: 4.1, 4.8
• Grade Five: 5.1, 5.7
• Grade Six: 6.1, 6.2, 6.11
• Earth Science: ES.1, ES.2, ES.3, ES.8, ES.9

History and Social Science:

• Grade Four: 4.2
• Grade Five: 5.3

Background

    This vast Bay watershed encompasses many different land features: mountans, forests, fields, wetlands, farms and cities. As rainwater falls on teh watershed, it nourishes plants quenches the thirst of man and other living creatures, soaks into the ground, or runs off the land to join streams and rivers. Along the way, it picks up an assortment of substances: soil particles eroded from bare ground; decaying organic matter from pastures and forest; oil from city streets; and fertiliczers and pesticides from lawns and fields. Some of these substances benefit Bay life, some are detrimental even in small quantities, and most are harmful in large doses. Unfortunately, many human activities on land do result in excessive loads of substances being washed into the Bay.

    People can reduce their impact on the Bay and its tributaries through careful planning and conservative living. Understanding the watershed concept and how pollution enters the waterways are the first steps to solving the problem.

Materials

Per group:

• aluminum foil
• shallow baking pans or aluminum foil roasting pans (one per group)
• packets of brightly colored powdered drink mix
• food coloring
• paper cups (two per group, one with holes punched in bottom)
• bucket and several liters of water
• two clear plastic cups
• map of the Bay watershed
• VA state map
• topographic map of the watershed of the area around the park (optional)

Resources:

Aquatic Project WILD. 1987.

"Watershed;" "Where Does Water Go After School?" Western Regional Environmental Education Councel. Write: VA Dept. Game and Inland Fisheries, 4010 W. Broad St., Richmond, VA 23230 (804) 367-1000

NatureScope: Geology, The Active Earth. 1987.

"Shaping the Landscape." National Wildlife Federation, Washington, DC. Silver Burdett Science Series (5th grade science text).

Slattery, B. 1989

"Bay B C's." U.S. Fish and Wildlife Service.

The Class Project, 1989.

"The Earth's Sponge." National Wildlife Federation, Washington, DC.

Procedure

Before the Trip:

1. Introduce the idea of a watershed. Explain that each river, creek, and stream have their own watersheds and that smaller watersheds join to make larger watersheds. Review the principles of the water cycle. How are rain, streams, rivers, the Bay, and the watershed connected or related to one another?

2. Using a map of Virginia or the central Atlantic states, students locte the rivers flowing into the Chesapeake Bay and determine the limits of the Bay's watershed. Locate the park to be visited on the map.

3. Divide the class into teams of about four students each.

4. Each team makes a model of a waterwhed: Use a piece of foil in an aluminum baking pan to make a topographic representation of a watershed. Crinkle the foil to make mountains, hills, and valleys, and form a basin or bay at the end opposite the mountains.

5. Explain that there are two types of pollution, point source and nonpoint source. Point source pollution has an identifiable source, such as waste discharging from a pipe. Nonpoint source pollution cannot be strictly identified as to its source because it originates over a large area. Nonpoint pollution includes stormwater runoff, atmospheric deposition (airborne pollutants such as sulfur, lead, and nitrogen emitted from cars and smokestacks), failing septic systems, and contaminated groundwater..

6. Sprinkle some powdered drink mix over an area of the watershed to represent a nonpoint source pollutant. Make it "rain" on the watershed using a paper cup with holes punched in the bottom and observe the way the rain moves the pollutant.

7. Repeat using food coloring (point source pollution) placed in a small spot. Make it "rain" again, and observe the movement of the pollutant.

8. Discuss more specific examples of runoff and how these affect the water. How is this model similar to a real watershed? How is it different?

At the Park:

1. Find two small areas (approximately 10 square feet or so) close together, one vegetated and one base, with similar slopes. Stdents describe the features of these portions of the watershed - slope, plants, etc.

2. With a bucket or sprinkling can, make it "rain" at the highest points in the two areas. Continue poyuring until it becomes evident that different things are happening on the two plots. Students should describe what they observe.
   
   • What happens to the water?
   • What happens to the soil?
   • Where there is little grass in the plot, the water may carve its own "river" - is this how some rivers could be formed????

3. With clear cups, collect a little runoff from both areas. Where was water easier to collect? Why? Does the water in the two cups look different?

4. Lead the class to a point of relatively high elevationl P{osition the students a few feet from each other and have the students pretend they are raindrops that just hit the ground.

5. The students then walk the path that they think the rain would take if it were running over the land without soaking in or being taken up by plants. While walking, they record or discuss features that might affect the rain or that the rain might pickup as it makes its way downhill -- soil particles, leaves, rocks, chemicals, litter, etc., and note any signs of erosion. If possible, walk all the way to a body of water, such as a stream or river. Advanced students can try tracing their paths on topographic maps.

6. Once the water is reached, use a map or maps to trace the rest of the path to the Bay and to the Atlantic Ocean. Discuss:
   
   • Are there other land features, including man-made, that the water flows past that would affect its quality (cities, farms, factories, etc.)?
   • Would the rain or river water change any of the land? List the things that the water might pick up as it flows to the ocean.
   • How could people in the watershed help keep pollutants out of the water?

Where in the Park?

When

    These activities can be done at any time, but after a recent rain it may be easier to observe the effect of water poured on the land.

Variations

1. In small groups, students adjust the topography of their aluminum foil watersheds so that several tributary watersheds are produced. Prepare original topographic maps, noting each watershed on the map.

2. Make posters illustrating the effects of pollutants entering a watershed and the waterways.

   Gifted/Advanced:

       Before the field trip, students could read "Odyssey" by Aldo Leopold, which describes the adventures of atom "X" as it makes its way from the mountains to the sea. During the trip, as they walk the path of a raindrop to the water, students make notes on the possible adventures which might befall a molecule of water here, as it cycles its way to the Bay. After returning to school, students use these notes to write essays. require that a minimum of six adventures be described. (Leopold, A. Reprinted 1966. "Odyssey." A Sand County Almanac. Oxford University Press.)

Top of Lesson