Watersheds
Where does your drinking water come from? Is it treated before it comes into your home? If so, where is it treated, and how? Clean water is essential to life, but many people are unfamiliar with the answers to these and related questions. By encouraging students to do authentic scientific research on the watersheds in their communities, EI facilitates a better understanding of water resources and the scientific process.

What is a watershed?
A watershed is the area of land that drains into a stream, river, lake, or other body of water. Watersheds can be both large and small. For example, a small stream in a rural neighborhood may have a tiny watershed. In contrast, the Mississippi River's watershed covers almost two-thirds of North America!

Consider a small stream high in the mountains. Its watershed consists of the few underground springs and precipitation runoff from the land just above it. As the stream flows downhill, it enters successively larger bodies of water, including a bigger stream, a river, perhaps a lake, and eventually the ocean - all of which have correspondingly larger watersheds. Watersheds of all sizes have complex processes affecting the quality of the water draining out of them.

Of course, humans use water for drinking, cleaning, cooking, and carrying away waste. To obtain water for these uses, we have built pipes, dams, water treatment plants (both for treating water before it enters our homes and after it leaves them), and other structures for transporting water. Because we depend on water that is free of pollutants and as clean as possible, it is often necessary to responsibly manage the watersheds that provide the water we use. Indeed, many towns and cities have watershed management plans to ensure the quality - and quantity - of their water sources.

As watersheds become developed, stormwater runs off from roads, fields, parking lots, and buildings. Roadside ditches are designed and managed to prevent flooding of these structures by providing rapid flow of runoff water. However, impacts on quantity and quality of water in streams and lakes typically is not considered when ditches are designed, built, and maintained. Through investigations of roadside ditches, students can learn about surface water runoff and its impact on downstream waters.

Student investigations of stormwater runoff in roadside ditches

Cornell Scientific Inquiry Series
Watershed Dynamics, the fourth book in the Cornell Environmental Inquiry Series, is a comprehensive guide to student watershed research. Learn more Watershed Dynamics and download related files.

Other Ideas for Student Water Quality Experiments (PDF files):

• Acid Rain Experiments
• Eutrophication Experiments
• Diurnal Cycling Experiments

Watershed Links

GIS links
Watershed resource links
EI's Engineering Design Challenges