Measuring Discharge and Flow in the Rum River

Sarah Haberman, Fred Moore Middle School, Anoka, MN
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Summary

In this field lab, students will travel to a small stream, in order to predict, measure, and compare and contrast velocity at the point bar and cut bank. Students will also gather data at different locations to determine the total discharge. Students will present their findings to the class, and make conclusions about how velocity affects erosion and discharge.

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Learning Goals

Goals:
1. Students will make predictions regarding stream discharge and velocity at different points in a stream.
2. Students will compare, contrast, and make conclusions about water velocity of different places on a stream and how the velocity affects erosion.
3. Students will determine how to use and use materials to calculate discharge of a stream
Higher-order thinking skills: critical thinking, data analysis, experiment development.
Other skills: Observation, field techniques, concluding, questioning, predicting.
Key Concepts
1. Water velocity is at a cut bank is faster than at a point bar.
2. A stream's discharge is consistent throughout the stream.
Vocabulary:
Stream discharge, velocity, point bar, cut bank

Context for Use

A group of 30 students at a time will be taken to a small, nearby stream over a period of two days. Day one will have the students measure the velocity of a stream at the point bar and cut bank. Day two will be measuring the stream's discharge. The students will summarize and present their results in the classroom on the third day. The periods will each be 55 minutes. The stream is within walking distance from the school. Prior to this activity students will need to have an idea of velocity and general measurement in order to complete the measurements. During the activity, the vocabulary terms point bar, cut bank, and discharge will also need to be introduced. This fits into curriculum during weather and erosion, specifically with water.

Description and Teaching Materials

In this field lab, students will travel to the Rum River in Anoka in order to compare and contrast water flow velocity on opposite points of a stream, conclude how velocity affects erosion, and calculate the total discharge for the stream. First, students will make general observations of the speed of the river in different areas and make predictions based on their observations. Next, the students will develop a method to test the velocity using oranges, metes sticks, and stopwatches. Students will use the materials to determine the velocity at both the point bar and the cut bank and compare their results. As a group students will discuss the differences, both in point bar, cut bank, and other points on the stream, how that affects erosion, and whether or not that will affect the total discharge of the stream. The students will then test and calculate the total discharge of the stream and compare their findings with their predictions, as well as other groups. Finally, the students will put together a summary of stream velocity, erosion, and discharge, which they will present to the rest of the groups. Finally, the all of the groups will discuss the total discharge on different areas on stream, and whether or not it is affected by differing velocities.

Teaching Notes and Tips

Students should be divided into groups of 4 in order to ensure everyone is active and involved. As a management technique, it is important to pick specific locations on the stream to keep groups separated and confided, but it also ensures that every aspect of the stream is represented.

Assessment

Students will be turning in a results packet including their original observations and predictions of the stream, their gathered data including measurements of velocity and total discharge, and their final summary of their findings. Throughout the field study, it is important to visit with each group to ensure they are on a correct path; this would be the time to remind the students of the essential vocabulary.

Standards

7.1.1.2.1 – Scientific Inquiry, generate questions
7.1.1.2.2- Scientific Inquiry, plan and conduct and controlled experiment
7.1.1.2.3 – Scientific Inquiry, generate a conclusion
7.1.1.2.4 – Scientific Inquiry, evaluate explanations
8.1.1.2.1 – Scientific Inquiry, develop predictions and explanations
8.3.1.2.2 – Weathering and erosion

References and Resources