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Activity S-2: Use Your Head, Protect Your Watershed!
This youth activity is one in a series of two activities that can be used to introduce watershed concepts.  This activity is best suited for youth in grades 3-12.  The younger audiences will enjoy exploring different classes of watersheds and pollution while integrating information about geography and economy.  Older audiences will find interest in graphing and integrating math and chemistry into this project.

To describe and identify the land use activities within a watershed by analyzing its water quality.
(This information was taken in part from CLEAN WATER in YOUR WATERSHED: A Citizens Guide to Watershed Protection by the Terrene Institute, Washington, D.C. 1993.)
A watershed is an area of land from which all the water drains to the same location such as a stream, pond, lake, river, wetland, or estuary.  A watershed can be large, like the Mississippi River drainage basin, or very small, such as the 40 acres that drain to a farm pond.  Large watersheds are often called basins and contain many smaller watersheds.

Nonpoint source pollution has many different sources, usually associated with rainfall and snowmelt runoff moving over and through the ground, carrying natural and human-made pollutants into lakes, rivers, streams, wetlands, estuaries, and underground water.  Pollutants accumulate in watersheds as a result of various practices and natural events.  These pollutants, while sometimes inevitable, drastically alter the state of the ecosystem.  If we can determine the type of pollutant, then we can not only classify the source of the pollutant, but take preventative measures to alleviate any further contamination.

* candy (i.e., Skittles ,M+Ms )
* plastic baggies (1 per student or per group of students; snack or sandwich size)
* graph paper (1 sheet per student or per group of students)
* colored pencils (1 set per student or per group of students)
  1. Divide the candy amongst the baggies.  You may either have 1 baggie per student or 1 baggie per group of students.  You should have about 30 pieces of candy per baggie.  Each baggie represents a watershed.

  2. Use the table at the end of this section to initiate a discussion about the pollution that can come from different land use activities.

  3. Have the class assign a pollutant (or group of pollutants) to each color of candy.  For example, brown=sediment, red=pesticides, green=fertilizers or nitrogen.  There is chart at end of this section which gives an example of a color/contaminant chart.

  4. Distribute graph paper to each student (or group).  Have the students draw a bar graph of the pollutants in their watershed.  Label the x-axis with the names of the candy colors or pollutants and the y-axis with numbers.

  5. Give each group a baggie with candy.  Have the students separate and count the number of each color and graph them on the paper.  The students can use colored pencils to draw in the bars.  Have the students try to determine what land use activities are occurring in their watershed by the pollutant profile.


Discuss how each watershed is different and while some watersheds might contain an abundance of one certain type of pollutant, that almost all forms of pollutants can be found (even in small amounts).  Can they classify their watershed, i.e., agricultural, industrial, urban, forest?

This activity was developed by Dr. Kitt Farrell-Poe, September 1997.

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Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director, Cooperative Extension, College of Agriculture, The University of Arizona. The University of Arizona College of Agriculture is an Equal Opportunity employer, authorized to provide research, educational information, and other services only to individuals and institutions that function without regard to sex, race, religion, color, national origin, age, Viet Nam Era Veteran's status, or disability.

For problems or questions regarding this web contact Dr. Kitt Farrell-Poe.
This document was last modified: 31-Aug-2005 .

Land use, their associated activities, and resulting pollutants.
Land Use
Pollution Problems
Agriculture tillage, cultivation, pest control, fertilization, animal waste management sediment, nitrate, ammonia, phosphate, pesticides, bacteria
Construction land clearing and grading sediment
Forestry timber harvesting, road construction, fire control, weed control sediment, pesticides
Wastewater Disposal septic systems bacteria, nitrate, phosphate
Surface Mining dirt, gravel, mineral excavation sediment, heavy metals, acid drainage, nutrients
Urban Storm Runoff automobile maintenance, lawn and garden care, painting oil, gas, antifreeze, nutrients, pesticides, paint

Color Contaminant
Dark Brown:
Light Brown: