Part 1: Straws in the Colorado River: Will We Run Out of Water?

In Part 1 of this lab, students take a journey down the Colorado River to give them perspective on the scope of the watershed and how various stakeholders have siphoned the water from the river to serve seven western states' needs. Then they collect data concerning where the water comes from, who is using the water and how much they are using, and what the future may hold for the people living in the basin.

Part 2: Explore the Colorado River Basin

In Part 2 of this lab, students explore aspects of the Colorado River Basin using a a video, interactives and tools such as Google Maps.

Part 3: Understanding Long-term Stream Flow Using Tree-ring Science

In Part 3, students work in teams and use a quantitative method to measure the width of tree rings (using ImageJ) to produce a graph of the climate record in the Colorado River basin over the past 120 years. Then they compare their results with stream flow data to determine how good a proxy tree rings are for measuring changes in the flow volume of the Colorado River.

To download one of the PDF or Word files below, right-click (control-click on a Mac) the link and choose "Save File As" or "Save Link As."

• Student Activity Sheet for Lab 4 (PDF (Acrobat (PDF) 232kB Mar14 19))(Word (Microsoft Word 2007 (.docx) 68kB Mar14 19));
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  • To add a hands-on component, consider purchasing a core apparatus (about $240) Forestry Suppliers. Visit The Ultimate Tree-Ring Webpages for tips, advice on cleaning kits for your core apparatus, and more information.
  • Have ImageJ (more info) downloaded on all student computers or give them the link to download it themselves.
  • If you would like students to learn the rudiments of ImageJ on an individual basis have them go through the ImageJ Beginner's Tutorial.
  • Go through each section of the lab. Download and print the student worksheets unless students are going to print themselves at home.
  • Go through each section of this part of the lab. Students may need help interpreting some of the graphs and figures.
  • You can choose to do this part of the lab as homework or have students complete each section in turn and go over the questions addressed by each one in a class discussion.
  • Read the Overpeck paper .
  • For the second part of Part 2 and for Part 3, students will work in small groups. Divide the students into groups of 4 four or five. Each group will be assigned one of the three study sites to focus on. When they are in their groups, they should elect a member to act as the "PI" (principle investigator) of their research group. The PI will organize and guide the completion of your final report. Then group members should decide who will act as:
  • Data crunchers - the member(s) who will use ImageJ to measure and record the data from two core samples taken from a single tree on your study site.
  • Tech person - the member who will be responsible for producing the graphs of the data in Excel or similar program and will procure the necessary images for the report.
  • co-PI - the member who will assemble the various parts of the presentation with the PI and produce the Powerpoint of the group's results and final report.
  • Familiarize yourself with the Colorado River Basin Interactive Map.
  • If students have never used Google Earth before, take them through a short tutorial of how to navigate in the program and how to type a location in the Search Box to go to a specific location.Or, point students to a 7 minute Google Earth Tutorial for Beginners tutorial.
  • If students are not familiar with measuring on images with ImageJ, have them review the ImageJ tutorial found here.
  • If you are not familiar with measuring on images with ImageJ, review the ImageJ tutorial found here.
  • Decide how you want to divide the dataset, the number of decades of tree ring data that your students will measure using ImageJ. You can have students select their own interval of rings or you can assign them. Keep in mind that either the students or you will need to assemble all the parts of the data and create a graph for the class to analyze and discuss.
  • Bring up the image and go through how to set scale and take a sample measurement if possible.
    • Climate Fluctuations, Drought, and Flow of the Colorado River (2004) Webb, R., Hereford, R., McCabe, R. USGS Factsheet https://pubs.usgs.gov/fs/2004/3062/
    • Climate Change Impacts on Hydropower in the Colorado River Basin (2012) Thiel, Aaron/Center For Water Policy/University of Wisconsin-Milwaukee
    • Gray, S. T., J. J. Lukas, and C. A. Woodhouse (2011), Millennial-length records of streamflow from three major Upper Colorado River Tributaries 1, J. Am. Water Resour. Assoc., 47(4), 702"712.
    • Jacoby, G. C., and C. W. Stockton (1976 ), Long-term surface-water supply and streamflow trends in the Upper Colorado River basin based on tree-ring analyses, Natl. Sci. Found. Lake Powell Res. Proj. Bull., 18, 70.
    • Meko, D. M., C. A. Woodhouse, C. A. Baisan, T. Knight, J. J. Lukas, M. K. Hughes, and M. W. Salzer (2007), Medieval drought in the upper Colorado River Basin, Geophys. Res. Lett., 34, L10705, doi:10.1029/2007GL029988.
    • Woodhouse, C. A., and J. J. Lukas (2006), Drought, tree rings and water resource management in Colorado, Can. Water Resour. J., 31(4),297"310.
    • Woodhouse, C. A., S. T. Gray, and D. M. Meko (2006), Updated streamflow reconstructions for the Upper Colorado River Basin, Water Resour. Res., 42, W05415, doi:10.1029/2005WR004455
    • Drying of the West, National Geographic. February 2008. By Robert Kunzig, Photographed by Vincent Laforet http://ngm.nationalgeographic.com/2008/02/drying-west/kunzig-text
    • TreeFlow (a comprehensive web resource for tree-ring reconstructions of streamflow and climate, providing easy access to reconstruction data as well as information about how the data were developed and can be used): http://www.treeflow.info
    • TreeFlow: Colorado River Streamflow: A Paleo Perspective http://www.treeflow.info/perspective
    • IPCC Report, Chapter 2 - Future Climate Changes, Risks, and Impacts