Watershed Detectives

    Watershed Detectives

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    To describe and identify the link between land use activities and water quality.


    In this lesson, students will analyze water samples from different fictional watersheds. Students are given a description of each watershed, including their unique land uses, along with spiked water samples. Students test the water samples for turbidity, pH, and nitrates. Information about the temperature and dissolved oxygen levels are given. Students interpret the water quality data and land use clues to match the water samples to the watersheds. They also discuss approaches to improving or protecting water quality in different settings.

    See the background section for some general background information as well as how to prepare the water samples. Also, see discussion questions for some leading questions to help guide discussions.

    This lesson is designed in three parts:

    1. A classroom activity that helps students analyze water samples and determine their source.
    2.  Follow up STEM activities where students apply their knowledge of water quality.
    3.  And watershed connections.

    Materials Needed:


    *Click here for information on purchasing equipment or supplies or creating your own equipment. Contact USU Water Quality Extension (waterquality@usu.edu or 435-797-2580) for information on borrowing equipment.

    Classroom Activity:

    Before you begin, review the background section and prepare the water samples.

    1. Discuss with your students what a watershed is and the different types of land uses that can occur in a watershed.  (Be sure you cover each land use shown in the watershed sketches).
    2. Explain to your students that each of these land uses impact the quality of the water in various ways and that during this lesson they will be learning about those impacts. 
    3. Show students the watershed sketches and talk about the land uses in each watershed.  Have them speculate what type of impacts each use might have on the quality of the water
    4. Explain to your students how turbidity, nitrates, pH, dissolved oxygen and temperature are affected by different land uses and natural and human activities.  As you go through each one, demonstrate how to do the measurement.  Sampling instructions: turbidity, nitrates, and pH (dissolved oxygen and temperature are given).
      1. Discuss natural and human activities that will raise or lower water temperature. Examples: Natural – elevation, riparian vegetation, and source.  Human – loss of riparian vegetation, climate change, discharge from industrial and urban areas. 
      2. Discuss natural and human activities that will change turbidity. Examples:  natural – geology (a good example is the difference between a stream in the Uintas (where the geology is primarily granite and other material that does not erode easily) and the Colorado River (where the geology is primarily sandstone and other material that does erode easily).  Human – phytoplankton, agricultural runoff, runoff from construction areas, stormwater runoff.
      3. Discuss the pH scale. Discuss natural and human activities that will alter pH.  Examples: Natural – geology, acid rain, pine forests.  Human – mine drainage.  Mention that most streams in Utah are basic (limestone, calcium carbonate in bedrock buffers acid snow melt). 
      4. Discuss natural and human activities that are a source of nitrates.  Example: Human – fertilizers (agriculture, urban lawns and gardens), animal waste (livestock and pets).
      5. Discuss dissolved oxygen and the natural and human activities that influence the amount of dissolved oxygen. Discuss what will influence the amount of dissolved oxygen in a water body (temperature, turbulence, and salinity).
    5. Show the students the water samples and explain that they will measure turbidity, pH and nitrates for each sample.  Dissolved oxygen and temperature will be given to them. They will then use that information to determine which watershed each sample came from.
    6. Divide the students into groups and give each group a water sample and the sampling equipment. 
    7. Have each group report their results and the watershed they think their samples came from. 
    8. Write the results for all groups on a whiteboard. Discuss which watershed each sample came from and have the students tell you why. Discuss the land use activities that changed each chemical measurement (see Table 1). Have the students compare the parameters of each watershed with the Utah's Requirements Sheet. Review with the class each watershed, the land uses occurring there and reveal which samples came from which watershed. Also, see discussion questions for some leading questions to help guide discussions.


    STEM Activity:


    1.  Use your data to create graphs and comparisons. You can view examples of some graphed data here.

    2.  Have students learn about the "beneficial use designations" of streams. Discuss whether or not each water sample would meet each beneficial use.

    3. Compare your results with results collected from actual rivers and lakes.

    4. Research best management practices (BMP's) that could reduce pollution in each of the fictional watersheds.

    5. Have students interpret maps with water quality data. These maps were created by teachers involved in CMaP. Students could also monitor water quality data and use GPS to create their own maps.


    Watershed Connections

    Watersheds are natural outdoor laboratories. Use the map below to find the watershed you teach in. Use the watershed connections in the Stream Side Science lessons to learn how you can use specific stream locations, local data sources, local contact and other information in your area to make the Stream Side Science experience more relevant to your students.   
    What watershed do you live in?
    If you live in Utah, the map below shows all of the watersheds that either drain into or out of Utah.
    OR go to Surf Your Watershed to locate you watershed anywhere in the U.S. 

    Utah Watersheds


    Curriculum and Teacher Materials 

    Core Alignments by Grade:

    6th Grade:

    • No Alignment

    7th Grade:

    • No Alignment

    8th Grade:

    High School: