In the mid-1900s two man-made dams were constructed along the Colorado River to form reservoirs (Lake Powell and Lake Mead) that could store water and provide power for the growing population in the western United States. As recently as the year 2000, these reservoirs were full of water. However, over the past two decades the water levels in both reservoirs have dropped significantly leaving “bathtub rings” behind on the surrounding bedrock - a sign of what used to be. After analyzing temperature and precipitation data, students identify the root cause of the megadrought in the Colorado River Basin and discuss strategies to reverse/reduce drought in the region.
Context for Use
What Students Will Do
- Analyze and interpret data to evaluate the cause of a decades-long drought (megadrought) across the Colorado RIver Basin.
- Construct conceptual models to explain the cause of megadrought conditions across the Colorado River Basin.
Part 1 (20 minutes) Eliciting Students' Ideas
- Students document noticings/wonderings about drought-related images and then reflect on their own experiences with drought.
Part 2 (40 minutes) Identifying Important Science Ideas
- Students engage with an interactive reading to 1) identify similarities between the opening scenario prompt and the work of Seth Arens, a hydrologist who studies the connections between climate change and drought, and 2) make predictions as it relates to Seth's research question, "What is causing the megadrought in the Colorado River Basin?"
Part 3 (30 minutes) Supporting Ongoing Changes in Thinking
- Students test their prediction about what is causing the megadrought in the Colorado River Basin by analyzing regional temperature and precipitation data over time.
Part 4 (30 minutes) Constructing Evidence-Based Explanations
- Students reflect on evidence gathered during parts 1-3 and construct a final explanatory model for the question, "What is causing the megadrought in the Colorado River Basin?"