Examining topography and stream discharge at Sherburne National Wildlife Refuge

Todd Koenig
Zimmerman High School
ISD 728
Zimmerman, MN
I will be using a modified concept of the contour mapping exercise we did at St. Thomas and the Hydrology flow lab we preformed at Coon Creek.

Summary

In this inquiry based geologic field lab students will be estimating and measuring stream flow. Students will be collecting data from an existing small stream or river (shallow water no higher than knee level) they will be visually estimating this flow as well as performing the orange test to collect this data. Students will write a lab report and calculate the data to document their results. Students will also need to make careful observations of the stream so they can hypothesis the discharge of the dry streambed. At the dry streambed students will use their already honed topography skills to map out one foot topography lines in a 100 foot section of the dry streambed to help them estimate flow discharge. Students will then enter their hypothesis into their lab report with evidence to that backs up their observations.

Used this activity? Share your experiences and modifications

Learning Goals

Goals: Students will work in groups to problem solve stream discharge by both estimating and measuring and collecting data.

Students will graph actual contour lines and using these measurements to hypothesis stream discharge and sediment load from a restored wetland (impoundment) using a dry stream bed.

Vocabulary Words: Contour Line, Hydrology, Watershed, Sediment, Stream Flow, and Velocity

Context for Use

This project is designed for a high school class but with direction middle school students could perform this activity as well. I will be doing this with approximately 80 students and about 4 additional adults to help supervise. This activity is set up as inquiry based field exercise/lab. I will be taking about a day but there will be additional tours of the Refuge and headquarters as well as occupational discussions with refuge staff.
To do the topography activity you will need the following materials:
1 per group -Jacob's staff (red and white survey staff) or a 6-8 foot ¾ inch dowel marked off in one foot intervals.
-A simple small carpenter's sighting level this looks like a small scope with a level built into it. (Found at a hardware store)
-Survey/marking tape (3-4 colors) (Found at a hardware store)

To do the stream flow activity you will need the following materials:
1 per group
-Oranges (the fruit)
-Stopwatch
-Meter stick or roll up waterproof tape
-Calculator

Students will have done simple topography mapping in the school yard previous to mapping out the dry steam bed. This could be modified to any moving body of water and if there is access to some sort of dry river/stream system this could be done it would be best if they are in close proximity to one another.

Description and Teaching Materials

The students will first have to estimate the flow discharge of the stream by some means that they decide as a group meter sticks and waterproof tapes will be available for measurement purposes (width and depth of the stream). They will have to come up with some method to measure flow (this could be sunflower seeds, a stick, or aquatic weeds most likely will be used by students). They will then calculate the discharge by measuring the depth of the stream and multiplying by the width of the stream and multiplying by the velocity at that point (this is measured in meters per second). They will then use oranges as a float, they are very close to neutral buoyancy so they will not be affected by wind (these were and are used still in some places verses the expensive mechanical flow meters). Now for a few tips, you will have to instruct students when using the oranges if you want your students to collect accurate data. The oranges need to be placed in the water not dropped which will cause them to bounce down stream. Impact with the ground will reduce your actual measured stream velocity. Also make sure that you don't place the orange directly at the one meter mark and measure downstream the orange will not immediately reach the current stream velocity. It would be best to place the orange 2 meters upstream and measure only the last meter of travel to ensure much more accurate results.

Example below:

EXAMPLE: Morgan, Tyler, Abby, and Joe measure stream width, depth, and velocity for Mink Creek. Mink Creek is 4.3 meters wide.


(meters) Stream Depth Stream Velocity (meters/seconds)
Spot 1 0.18m 1 meter/7 seconds (0.143)
Spot 2 0.34m 1 meter/4 seconds (0.25)
Spot 3 0.56m 1 meter/3 seconds (0.33)
Spot 4 0.35m 1 meter/6 seconds (0.17)

Total Flow = (1 m * 0.18 m * 0.143 m/s) + (1 m * 0.34 m * 0.25 m/s) + (1 m * 0.56 m * 0.33 m/s) + (1 m * 0.35 m * 0.17 m/s) = 0.36 m3/second

When plotting the elevation on the dry streambed students will use the Jacob's staff or a dowel marked of in 1 foot increments. This will involve teamwork to perform the live topography map. Each group will be assigned an elevation and they will use the simple carpenters sighting level to direct the other students where to mark flags and tie on the survey tape they will continue through the dry stream bed for a bout 100 feet. When finished there should be 4 minimum lines that the class can use as an actual live topography map. They can then use these lines to estimate and calculate a mock flow discharge of the dry streambed. For a greater affect you could mark every 6 inches vs. 1 foot. One or both sides of the dry streambed could be mapped. This will give a very interactive live model to use. Questions and Lab Sheet (Microsoft Word 31kB Aug3 09)

Teaching Notes and Tips

Make sure you find a hard bottomed stream that students can spread out in so they do not stir up excessive sediment for those downstream. Try to find a stream that remains relatively shallow ~ 2 feet maximum. There must be one chaperone on the stream bank with a cell phone for emergencies. The remaining chaperones should be in the water with the students. Shoes must remain on at all times and a first aid kit is a must.

Assessment

I will have the student's use the lab sheet provided to use as a reference and individual students will be entering their information into their journals that I will be checking at a later date. I will also be asking questions of all the groups as they are working on their tests to ensure they are on track. I will be also collecting the data on the stream bank and we will be discussing the data together as a class. This is an easy method to check to ensure groups were in the ball park for the activity.

Standards

6-12 Minnesota Earth Science Standards 2009

9.3.4.1.1 Land use and engineering mitigation 9.3.4.1.2 Human activity altering natural process

6-12 Minnesota Nature of Science and Engineering Standards 2009

9.1.3.1.1 Describing a system and its subsystems 9.1.3.1.2 Identify properties and interaction of its parts
9.1.3.2.2 Possible careers in science and engineering 9.1.3.4.3 Select and use appropriate numeric representations to communicate results 9.1.3.4.6 Analyze strengths and limitations of models

References and Resources