This lesson plan was created by after being a part of the Arctic Glacial Lakes PolarTREC Expedition. I was inspired by the massive amount of data collected over the course of the research project and the complexity of hydrology in glaciated and non-glaciated basins in the Brooks Range of Alaska. Students will work together to make hypotheses about patterns in an actual data set and will attempt to understand the variables that influence discharge and sediment load of an Arctic creek.
- Students practice manipulating and searching for patterns in large data sets
- Students understand that sediment load is determined by the discharge of a stream
- Students understand that discharge is influenced by temperature and precipitation, and those influences are affected by whether a basin is glaciated or not
- Students understand that Arctic hydrology is complex and that sediments are important to fluvial systems and ecosystems
- Teacher should use the graphs on the original spreadsheet to familiarize themselves with the graphs that students will produce and the patterns they will see.
- Teacher should familiarize themselves with the location using the photos provided
- Students should have access to computers (at least one per group) and graphing software: either google sheets or excel.
It will benefit students and teachers to read the journal posts from the Arctic Glacial Lakes expedition that detail the science of the expedition. These posts are labeled “The Science.” The following journals will be the most helpful for this lesson.
The Science: Arctic Glacial Lakes details the data collection, models, and goals of the Arctic Glacial Lakes project.
The Science: Why Study Mud? discusses the importance of studying sediments, which will help students understand the purpose of this activity.
The Science: Glaciers
will help students understand the importance of glaciers on hydrology and sedimentology.
Students should also have a good understanding of discharge, suspended sediment, and turbidity.
Discharge is the volume of water traveling in a waterway in a given amount of time.
Suspended sediment concentration is the amount of sediment of all grain sizes carried in the water, as measured by a certain mass of sediments in a certain volume of water. Generally, the higher the discharge, the greater the energy in the water, and thus more and larger sediments will be carried.
Turbidity is cloudiness of the water, and is determined by the amount of fine sediments, like fine silt, clay, and organic matter, that is in the water.
Students should also understand that Julian date is a count of days in the year, which allows us to easily graph a continuous passage of time. Decimals in the Julian data give the time of the day.
- Find Lake Peters on Google Earth, then find Carnivore Creek, Chamberlin Creek, NG1 and Chamberlin glacier. It may be helpful to have students trace the drainage basins for each of the creeks and look for key features (glaciers, multiple tributaries, etc). Pictures have been included in this lesson to help identify these locations.
- As a class, make predictions about how Carnivore Creek and NG-1 may differ. What variables (glaciers, size, precipitation, temperature, etc) may impact their discharge the most?
Divide students into small groups. Each group should graph one of the variables on the dataset over time. They should answer the following questions:
a. What patterns do you see in the data?
b. What might explain these patterns?
c. Make several hypotheses about how your variable might interact with the other variables.
d. Predict what trends you might see in the other groups’ graphs.
When students are ready, they should share their graph with the class a give a short informal presentation on their data. As students present, the other groups should check their predictions against the new data provided for them. This part could also be done as a jigsaw, creating new groups made of one student expert from each of the other groups.
- The lesson should end with a whole group discussion where students test their hypotheses against the new data, and look for trends across the data.
- Pressure is a very rough proxy for discharge. More pressure = more discharge. For better analyses, this measure would need to be calibrated with measurements from the field.
- NG 1 is not glaciated and has a small watershed, Carnivore Creek has many glaciated tributaries.
- Discharge of glaciated tributaries are likely to be more influence by temperature than non-glaciated
- Look for time lags in the larger tributary.
- Trends will be coarse. The intention of this exercise is to provoke thought and searching for patterns, NOT to come to conclusions based on statistically significant trends.
Data Set: Carnivore Creek and NG1 Data 2017
Photos from Google Earth
Students should be assessed in their presentations and in the final class discussion. Students may be formally assessed by a written paragraph, in which they make a claim about Arctic hydrological systems or sediments, and back that claim up with specific evidence from the data they saw in class or from the journal entries.
Rebecca Harris created this lesson. Please email her at the.rebecca.harris [at] gmail.com if you have any questions, comments, or feedback. I would love to hear from you! Data was organized by PolarTREC researcher Ellie Broadman, and provided by the Arctic Glacial Lakes Project. All data is preliminary, and some may have been adapted slightly to be more clear and concise for students, but to maintain the general trends. Special thanks Darrell Kaufman, Nicholas McKay, Lorna Thurston, David Fortin, Erik Schiefer, and the many other students and field assistants who generously provided the data.
HS ESS2-5, ESS2C
Utah Earth Science Standards
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