Small Scale Watershed - Schoolyard

Jason Cervenec

Byrd Polar and Climate Research Center

This activity was developed for an introductory geosciences class at the high school level. It has also been successfully used at the middle school, advanced high school, and university levels.

Students must understand the concept of a watershed and be able to measure lengths and calculate areas and volumes.

This activity is part of a sequence of activities (third of five activities).

• For convenience, measurements of volume rather than mass are often used by Earth scientists to monitor quantities of water in natural systems. (For this unit, we will ignore volume changes that occur due to changes in temperature.)
• Volumes of water added to a system or removed from a system are calculated by measuring and multiplying the length, width, and depth of water (volume = length x width x depth). A rain gauge provides a measure of depth (of precipitation that falls into the rain gauge), but the length and width of an area must also be measured. In a lake or reservoir, the volume of water can be calculated by the width and length of the water body multiplied by its average depth.
• In a soil and water system, where soil particles are assumed to be fixed, measuring the volume of water added to a system and the volume of water that leaves a system provides a way to estimate the volume of water that remains within a system.
• While water particles are most commonly added to a soil-water system via rain, they can be removed via evaporation, uptake by plants, surface runoff, and subsurface runoff. Water particles can also be stored in the system.
• Humans can alter evaporation, uptake by plants, surface runoff, and subsurface runoff through land use patterns (paving surfaces, re-grading slopes, or changing vegetation cover, for instance).
• Water naturally drains downhill (from a higher elevation to a lower elevation) due to gravity.
• A watershed is a region from which water drains to a common location.
• Scientists can create complex mathematical models that allow them to adjust many factors and predict the effect on storage, surface runoff, and subsurface runoff.
• Computers allow scientists to design more complex models and use the models over larger geographic areas or longer time scales than would otherwise be possible.
• As scientists collect additional data and improve their understanding of the Earth System, mathematical models are improved and more accurate predictions are made.
• Geoscientists are working on topics that have applications in everyday life.
• Geoscientists need to apply their content knowledge in innovative ways while working with a diverse range of partners to solve complex problems.

A deliberate effort has been made to use best practices in science education when designing this activity. The activity is based around the 5E Learning Cycle and each investigation is an exercise in guided inquiry. Topics are introduced conceptually in qualitative ways before engaging in extensive quantitative measurements and calculations. While lectures can be used to quickly communicate the information contained in the activity, an explicit goal is to provide ways for major objectives to be "uncovered" and discussed in context of content-rich learning experiences. Hopefully, this will engage students, link content with real-world situations, and support deep understanding and long-term retention of knowledge. This activity is best delivered with a connection to one or two local watersheds. Many online resources referenced in this activity allow teachers to tailor instruction to their local environment and identify local professional who can offer instructional support and serve as guest speakers or site visit coordinators.

During this third activity, students are taken to an area of the schoolyard that is readily seen from one location. The surface area and slope are measured, the land use is noted, and students estimate the volume of water that would fall during a rainfall event. Using a highly relevant question about flooding, students begin to understand the complexity of water flow within a watershed and benefits of utilizing computer models. The web application, titled Simple Storm Runoff Model for Geosciences Education, is introduced to allow students to use computer models to examine impacts of various storm events and land use changes to the schoolyard watershed. Free, online tools, such as Google Earth Pro, Google Maps, and various sites from the U.S. Geological Survey and National Weather Service are also introduced so that students can expand their geographic scope without needing to personally collect every measurement.

Byrd Polar and Climate Research Center: Water Cycles and Watersheds

Other Activities in this Series:

• Soup Can Water Budget
• Geo Sandbox Water Budget
• Large Scale Watershed - Battelle Darby Creek
• Land Use Change - Hellbranch Run