Educator Guide Lab 4: Sharing a River: The Colorado River Story
NOTE: To get access to the Answer Keys for the TREX labs, you will need to 'Request Instructor Access' using the the tab in the navigation menu on the left side of this page. This is to ensure that students are not simply downloading answer keys. Once you get notification that you have been approved, come back to this site and click on the guide that you want. You will enter your email and the guide will automatically be sent to you. You can do this for each of the five labs. Please allow at least 48 hours for approval.
Summary and Learning Objectives
In Lab 4, students take a journey to the Colorado River Basin near Lees Ferry. They explore aspects of the Colorado River Basin using a variety of resources, interactive maps, and tools such as Google Maps. This journey 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. In the final part of the lab, students use a quantitative method to measure the rings (using ImageJ) to produce a graph, a tree-ring chronology and use it to determine how water levels in the Colorado River Basin have varied over the past 200 years. They use the similar procedure followed by dendrochronologists to build a record that can be used to identify climate anomalies such as droughts. Then they compare their tree-ring width graph to published stream-flow data to determine how reliable a proxy tree rings are for measuring changes in the flow volume of the Colorado River.
Note: Please download the Student Activity Sheet (pdf or Word version) found in the Printable Materials section of this document if you wish to have students respond to Stop and Think questions as they go through the lab.
After completing this lab, students will be able to:
- describe how tree rings can be used to determine past stream flow and hydrological conditions in the Colorado River Basin.
- explain how proxy data, such as measurements of annual growth rings in trees, reveal the nature, scale, and duration of past climate events like droughts.
- explain how tree-ring data can leads to a deeper understanding of the challenges we face as a society and to helps to guide our decision making.
Activity Overview and Teaching Materials
Detailed overview of what students will do in each part of the lab and how long it will take.
Download and print files needed for each part of the lab, including student handouts and answer keys.