Classroom activities: Watersheds

This material is based on an article by Bureau of Land Management staff that appeared in Science and Children magazine, March 1998, published by the National Science Teachers Association. More information can be found on BLM's national environmental education webpages at Rivers Run Through It.

(1) Watersheds all around

(Example: Columbia River Basin) Generally, watersheds are described as the land that drains water from an area into its waterways such as streams and rivers. Watersheds are important physical features of the Interior Columbia Basin. The Scientific Analysis identified 2,500 watersheds in the basin. Watersheds can be large or small, draining a single valley or the entire basin. In this activity, students explore what a watershed is and how it works.

Materials: For this activity, you will need various sizes of rocks, a shallow plastic wash basin or tub (about 30x45 cm and 25 cm deep), heavy paper or a plastic tarp, a permanent marker, and a sprinkling can or spray bottle (to simulate rain).

Procedure: Place some rocks in the wash basin to build mountains and valleys. Cover with heavy paper or a plastic tarp. Ask the students to guess the route "rainwater" (from the sprinkling can or spray bottle) will take and where it will pool and be stored. Mark the predicted route with a permanent marker. Then test the students' predictions by spraying or sprinkling the area and observing the path of the water.

Watersheds are divided by areas of high elevation. When rain lands on the ground, it travels downhill to be drained. If water hit a mountaintop or ridgetop in the model and traveled in more than one direction, it is likely that there was more than one watershed. Most aquatic species, such as fish, do not cross watershed divides. How many watersheds did the students find in the model?

A healthy watershed not only stores but also filters water for a river or stream. When water hits the Earth and percolates through the soil into the water table, soil, rocks, and sand filter out many of the impurities carried by the water. To see how this might work, try the following activity.

Materials: You will need a flower pot with a drainage hole; a few cotton balls; some sand, soil, and gravel; and some muddy water.

Procedure: Plug the hole in the flower pot with cotton balls to represent subsoil, and fill the pot with a mixture of the sand, soil, and gravel. Slowly pour some muddy water into the pot and observe. The water running out of the drainage hole will be relatively clean.

(2) Watershed Scavenger Hunt

After discussing watersheds in the classroom, take students outdoors to see if they can spot signs of watersheds on the school grounds or in a nearby park. Begin by asking students where they think water will drain on the school grounds. Ask what clues they think they will find to help them identify a watershed.

Divide the class into groups of three, and send them outside to find the following items: a damp spot that might collect water; a stream of water and its tributaries; a gully created by water; a sign of erosion; a structure that would block or change the flow of water; and a place where water might be filtered. Back in the classroom, compare results and draw a map of the watersheds the students observed.

BLM California Earth Day resources/Environmental Education

BLM California News.bytes, issue 274

More about water and watersheds:

"Drinking Water & Ground Water Kids' Stuff" (U.S. Environmental Protection Agency)
 activities for kids and teachers, grades K-12

"Watersheds" (U.S. Environmental Protection Agency)
Answers to watershed questions, find your own watershed and more.

"Science in Your Watershed" (U.S. Geological Survey)
"These 'Information Discovery' pages are designed to help you find links to research, planning, management, and development activities at the watershed level." This page includes many links to other resources.

 "The Watershed Game" (University of Minnesota's Bell Museum of Natural History)
This "watershed-planning game" requires Apple's Quicktime plug-in for games above the novice level. Note: the "log-in" is actually just a box to type in your name that will appear on subsequent pages.)