In this activity, participants will interact with a watershed model built with simple materials, and see how pollution, chemicals, and runoff impact our local waterways.  They will observe how water carries materials from one place to another, and find out how runoff impacts the plants, animals, and people who live there.

This activity promotes awareness about healthy watersheds by first encouraging participants to consider how the flow of water contributes to the health of the surrounding environment, and then asking them to reflect on actions we can take to reduce pollution and runoff.

"All About Watersheds" may be paired with lessons about the water cycle and the negative effects that human development and land-use practices have had on the Chesapeake Bay.

While this resource has been designed for Elementary and Middle-School students, it can easily be adapted for older students, adults, and family audiences as well. To modify this resource for alternative formats and audiences, see our suggestions for Adaptations below.

All About Watersheds PDF - all the information on this website in a single document!

All About Watersheds Quick Guide - a PDF version you can print

Concepts to Explore:

A watershed is an area where all the rivers and streams drain to a common area.  Everyone in Maryland lives in the Chesapeake Bay Watershed, which is home to 18 million people, covers 64,000 square miles, and stretches across 6 states and the District of Columbia.

• The ratio of land to water in the Chesapeake Bay watershed is 14:1. What happens on the land affects the water.

• The difference between pervious/impervious surfaces, point/nonpoint source pollution.

• Without green areas that filter rainwater and help it slowly sink into the ground, stormwater picks up chemicals and carries pollution into the Bay.  Restoring the land by adding projects with native plants and trees can reverse the negative cycle created by human development.

• Some of the problems in the Bay may be fixed if we make simple changes to our behavior.

Move and Learn: Teach the “Watershed Dance.” (Click here for a PDF with instructions.)

Hands-On-Activity: Tell a story about the watershed using a mini watershed model you have built inside a tray with paper, rocks, foil, and sponges representing different elevations and pervious/impervious surfaces.  (Or, have your audience help build one, or let each member of the audience build their own!)  Using a spray bottle filled with water to represent rain, show how water was absorbed by the land prior to modern development.  Then, have participants remove wetlands/forests, add impervious surfaces, and introduce pollutants (colored water, cocoa, etc.) to show what has happened as more and more people have made this watershed their home.  Ask participants to share their observations and think about how development impacts the watershed.

Reflection: As a group, discuss the effect of the new landscape on all the living things who call it home, and have participants share how we might improve the health of our watershed.

Materials You Will Need *

• Paint tray (a roasting pan or a large lasagna pan will work too!)

• Aluminum foil

• Crumpled paper and/or rocks

• Bits of sponges and a leafy twig—if you can find one!

• Spray bottles to hold water for “rain”

• Squeeze bottles and powdered drink mix or food coloring to represent pollutants like fertilizer, pesticide, and oil

• Optional: Map of the Chesapeake Bay Watershed and copy of The Watershed Dance

• Optional: Map of the local watershed where your program is taking place

• Optional: A River Ran Wild: An Environmental History by Lynne Cherry.  Copies available through Marina; a 9-minute read-aloud version is available here.

* A box containing all of these materials is available for Stewards to check out.

Directions

Before your group arrives, make your model watershed.  Arrange crumpled pieces of paper and rocks in a paint tray; cover with a sheet of aluminum foil to create a landscape with varied elevation.  There should be smaller streams that combine and eventually run into the “bay” at the deep end of the tray.  Place sponges into a few crevices, and if possible, stick a leafy twig into a sponge to represent a tree with roots that absorb water.

1. Exploration: Begin by showing a map of the Chesapeake Bay, describe what a watershed is, and then have the group notice all the smaller rivers, creeks, and watersheds that are part of the Chesapeake Bay Watershed.  Ask the audience to point out the local watershed they are in, and emphasize that every drop of water from here, may eventually end up in the Bay.

Ask what river is close by.  What does the river provide?  Food?  Recreation?

2. Read Out Loud: Read A River Ran Wild by Lynne Cherry.  Cherry’s story describes a river in New Hampshire, but there are nice connections to the Chesapeake Bay Watershed.

3. Movement and Hands-On Activity: Turn to your watershed model and tell a story about what happens when a watershed gets developed by humans.   Again, define a watershed, but this time, get the audience to stand up and teach them the “Watershed Dance.”

As you tell your story, highlight different features of your watershed model.  You may find it helpful to touch on the following points:

• The foil is impermeable representing impervious surfaces, like buildings and roads. 

• The sponges represent permeable material, pervious parts of the landscape that help soak up water, like wetlands and tree roots.

• Participants can help spray water onto the model, showing how it flows to the Bay.

• Participants can sprinkle colored drink powder and cocoa powder to simulate sources of pollution and eroded soil; they can spray colored water representing fertilizer, motor oil, and other pollutants; they can drop small amounts of food coloring directly onto the model to represent point source pollution.

• What happens to the water flowing to the bay as more and more pollutants are added to the model?

• Notice when sponges are able to absorb runoff, when they become overwhelmed, and how observing the flow of water can help us predict an ideal spot to put a restoration project.

4. Continued Exploration Outside (optional): Go for a walk outside. Notice anything in the landscape that might be creating runoff for the Bay.  What can be done in this community to prevent runoff carrying pollution and soil from reaching the Bay?

5. Reflection: Get the audience thinking about what they've learned and how they can take action:

• What are some actions that contributed to the pollution of the Bay? 

• Where in your community is there bare ground and how does it affect the Bay?

• What effect would planting along the sides of a stream have on the Bay?

• Now that the Bay is in this condition, what can be done to ameliorate the situation? (Replant along shoreline. / Use permeable surfaces when possible. / Cover bare ground. / Dispose of toxins properly and reduce their use when possible.)

Suggested Reflection Prompts for Different Age Groups

• Grades K-2: Where does all the water eventually go no matter where it fell? What happens to the water along the way?  In what direction does water flow?  If something is upstream, where will it go?

• Grades 3-5: How does someone upriver affect the people down river? Where do you think runoff around here picks up pollutants? We can’t change how we got here, but how can we change for the future?  How can we get more runoff to soak in?  If people cut across off the sidewalk and create bare ground, what happens to that dirt when it rains?  What would keep it from eroding?

• Middle and High School: What are practices farmers and construction sites can perform to improve the Bay? How do wetlands, trees, and other plantings help the Bay?  What can you do to help prevent erosion?  What are some activities you could get involved in to help our watershed?

• Bonus High School/Adults: Some watersheds drain to the ocean, others drain to the Great Lakes. The watersheds of the Great Lakes Basin include land in the United States and Canada. What kind of challenges do you think might arise when a watershed is located in two different countries? What kind of cooperation might be needed to ensure the health of that watershed and how do you think this is similar or different to what happens in the Chesapeake Bay Watershed?

• Mixed Age / Families: As a family, what is something we are doing that adversely affects the Bay?  What is an action we as a family can take? We recommend drawing questions from our K-5 examples so that everyone will be able to participate.

Sample Lesson Plan

All About Watersheds Sample Lesson - click the link for a PDF of a sample lesson by Watershed Steward Nan Henry.

Many environmental organizations have designed activities for teachers and students to build their own watershed models.  Here are a few nice examples:

Project Wet - Seeing Watersheds

Michigan Sea Grant - DIY Watershed

EPA - Build Your Own Watershed

Sea Coast Science Center - Build Your Own Watershed

General Suggestions

* It’s so much fun when every participant in your program gets to build and play with their own watershed model!  For a great example of how this can work, see Watershed Steward Kate Vogel's Lesson Plan for her educational program "What is a Watershed?"  Kate debuted this program in Spring 2021 with the Crofton Library's Nature Explorers' Club and was able to keep all of the participating families safe and socially distanced throughout the entire session.

* Rather than building their own models for this lesson, Stewards can borrow WSA’s Watershed Model.  Check out our companion lesson, The Watershed Model.

* Oysters are a vital element in a healthy Chesapeake Bay, but are not a part of this model.  How might they be included?  Tiny sponges could be sprinkled in the basin to demonstrate how oysters filter the water, and then they could be removed to represent over harvesting.  Then, consider replacing them to show the impact of restoration and oyster farming.

Adaptations for Different Audiences

* Suggestions for Engaging Audiences in the following Age Groups:

• Grades K-2: The concept of a watershed and the fact that what happens on land affects the water is a good take away for this age.

• Grades 3-8: The lesson as written will demonstrate the concept of a watershed, types of pollution, and human impact in positive and negative ways.

• High School: More complex solutions to solve the problems of the Bay could include changes in zoning and other laws, better agricultural practices, advocating change through government.

• Mixed Age / Families: As a family, decide on behaviors that you are willing to do to improve the Bay. We recommend drawing questions from our K-5 examples so that everyone will be able to participate. 

Adaptations for Different Formats

This activity can be used in a variety of settings and contexts:

• Indoor Classroom Setting: Be sure to have towels or a means to clean up any spills from the model.

• Outdoor Classroom Setting: There might be an opportunity to create a model using rocks, moss, soil, and plants.  A mega watershed can be built using a tarp or shower curtain.  Rocks, sticks, or logs can create the elevations underneath.

• Program for a Medium or Large Audience: If there are enough materials, students may work in small groups to create their own models. Instructor should circulate to ensure the objectives are being met.  Come back together after modelling to discuss as large group.

• Table at a Community Event or Festival: If the audience is passing by and not staying for a whole presentation, have one model set up as a “pristine” bay and two others with pollution.  Demonstrate with the “rain” bottle the effect of runoff on each, and work to affect positive changes on the 2nd polluted model

• Steward Capstone Project: take the model to the locale where rainscaping will occur.  Model what the project is trying to  change, and point out in the real landscape where this takes place.

Key Terms

Watershed – an area where all the rivers and stream drain to a common area.

Runoff – water that flows downhill to a stream or other body of water.

Pervious – a material that allows water to pass through it.

Impervious – a material that does not allow water to pass through it.

Point Source Pollution – pollution that comes from a source we can easily identify, including pipes, sewers, channels, and ditches.

Nonpoint Source Pollution – pollution that does not come from one specific location; instead, it is runoff that collects and deposits pollution over a wide area.

Fun Facts

• The Bay holds about 18 trillion gallons of water. That amount of water would fill more than fifty billion bathtubs to the brim.

• Only about half of the water in the Bay comes from the ocean. The rest comes from the 64,000 square mile watershed, which extends approximately 524 miles from Cooperstown, New York to Norfolk, Virginia.

• Roughly 51 billion gallons of water enter the Bay each day from the 100,000 streams, creeks, and rivers that feed it.

• Every year, new parking lots, driveways, roofs, and other hardened surfaces from development convert land in the Chesapeake Bay region from great green filters to hard grey funnels. Every four years, an area of land the size of Washington, D.C. is lost.

• The Bay's fishing industry used to harvest tens of millions of bushels of oysters. Today, harvests have fallen to less than one percent of historic levels.

More Information

From The Changing Chesapeake: an introduction to the natural history and cultural history of the Chesapeake Bay by Valerie Chase

A good description of how water reaches the Bay:

Two things may happen to the rain and snow that falls on the Chesapeake Bay watershed, the land that drains into the Bay.  Some of the water runs over the land directly into streams and rivers and is called runoff.  The rest of the water soaks into the soil and moves down through soil and rock until it reaches the groundwaters where the spaces in the rock layers are full of water.  When the groundwater meets the surface of the earth, the water runs out as springs which also flow into screams and eventually into the Bay.  People tap into the groundwater when they dig a well.

From The Chesapeake Bay Foundation, “Polluted Stormwater Runoff: A Growing Threat”

The causes and effects of runoff:

Runoff pollution is increasing because the amount of land covered by parking lots, roads, roofs, and driveways, continues to grow. Meanwhile, forests, meadows, and other natural filters are disappearing, and manmade filtration systems to control runoff have not compensated for the loss.

With climate change potentially increasing the amount of precipitation, localized flooding can result as once designated "100-year storms" occur with greater frequency.

Only 10 to 20 percent of rain that falls in forests, fields, and other natural areas runs off, with the rest absorbed by soil and plants. By contrast, close to 100 percent of the rain that falls on concrete and other hard surface produces runoff. An inch of rain falling on an acre of hardened surface produces 27,000 gallons of runoff.

The Chesapeake Bay Foundation - The Chesapeake Bay Watershed 

The Chesapeake Bay Program – Modeling and the Chesapeake Bay

Caring for Our Watersheds – Watershed Information: Chesapeake Bay Watershed

USGS EarthWord - Watershed