Watershed in a Pan

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WATERSHED IN A PAN

While doing research for your environmental impact portfolio on the Chesapeake Bay, you have come across the term watershed several times. What exactly is a watershed? To understand how the Chesapeake Bay watershed works, you need to know a little bit about drainage. All of the water in the rivers and streams within the five states that surround the Bay, eventually drains into the Bay. The land which drains into the Chesapeake Bay is known as its watershed. In this investigation, you will analyze a watershed model in order to explain how human activities impact the quality of a watershed ecosystem.

Objective: When you have completed this investigation, you should be able to analyze a watershed model in order to explain how human activities impact the quality of a watershed ecosystem.

Procedure: Activity 1: Identifying a Watershed

1. Read the passage, “What is a Watershed,” in order to describe watersheds.

What is a Watershed?

A watershed is an area of land from which rainwater and snowmelt drain into a particular body of water. Watersheds may be small areas of land that drain water into streams or rivers or huge areas of land that drain into larger rivers, estuaries or deltas. Within each watershed, there are many smaller watersheds or subwatersheds. A watershed is usually named after the stream or river it drains into. By defining the boundary of a watershed, people can determine what type of pollution affects a body of water and the source of the pollution. Adapted from Chesapeake Bay: Watershed Activity Guide

1. Reread the passage and highlight the definition of a watershed and subwatershed.

1. Explain the significance of defining the area of a particular watershed. Use evidence from the passage to support your response.

Activity 2: The Chesapeake Bay Watershed

Now that you are familiar with what a watershed is, let’s look for watersheds closer to home.

1. Observe the map of the Chesapeake Bay Watershed on the Student Resource Sheet.
2. Identify and list with a partner the six states that make up the Chesapeake Bay Watershed.

1. Locate the Susquehanna River on the Chesapeake Bay Watershed map.

The Susquehanna River flows southward through New York, Pennsylvania, and Maryland to empty into the Chesapeake Bay. It provides over half of the freshwater that drains into the Bay. Today, the Susquehanna is severely degraded by nitrogen and phosphorous pollution and other contaminants. Excess animal manure, agricultural runoff, improperly treated sewage discharges, and urban stormwater drainage all end up in the Susquehanna River.

1. Describe how the Susquehanna River in New York and Pennsylvania impacts the quality of the Chesapeake Bay in Maryland.

Activity 3: A Watershed Model

Now that you are more familiar with what exactly a watershed is, let’s investigate further by making a model to illustrate how pollution and other substances get distributed in a watershed.

Materials

shallow baking pan soil

aluminum foil small cups or blocks

powdered drink mix watering can or spray

bottle

1. Read the procedures, “Making a Watershed Model.”

Making a Watershed Model

1. Obtain the materials for your group from your teacher.
2. Place small cups or blocks in one end of the shallow baking pan.
3. Prop the end with the cups or blocks using a book. See watershed model below.

1. Tear off a piece of aluminum foil the size of the pan.
2. Crinkle the foil and then cover the blocks or cups with the foil. This higher end of the model represents land with higher elevation or mountains within the watershed.
3. Make a basin or flat area in the foil at the end oppose the cups or blocks. This basin represents the large body of water into which the rivers and streams flow.
4. Spray water over the model watershed using a watering can.
5. Observe the movement of the water and record your observation in Chart 1, “Watershed Model Observations.”
6. Sprinkle the powdered drink mix on the higher elevation or mountains of the watershed model. The powdered drink mix represents pesticides used on a farmer’s field.
7. Spray water over the watershed and record the movement of the water and drink mix in Chart 1.
8. Sprinkle the soil on the higher elevation or mountains of the watershed. This represents soil that has been loosened due to construction for housing developments.
9. Spray water over the watershed and record the movement of the water and the soil in Chart 1.
10. Discard the materials as directed by your teacher.

1. Reread the procedures and determine what the crinkles in the foil represents in your watershed model.

1. Conduct the investigation.

CHART 1: WATERSHED MODEL OBSERVATIONS

1. Describe what happened to all of the substances (rain, fertilizer, soil) that were added to the watershed model. Use evidence from the investigation to support your response.

Class Discussion

Brainstorm with a group all the different human activities that may impact the Chesapeake watershed. Put a check next to those activities that you or your family do.

Analysis

1. Describe how the watershed model illustrates how human activities on the land impact watershed ecosystems. Use evidence from the investigation to support your response.

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1. Explain why it is important that all six states that make-up the Chesapeake Bay watershed work together to make and enforce laws to protect the Bay ecosystem. Use evidence from the investigation to support your response.

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THE CHESAPEAKE BAY WATERSHED