Investigating The South Crow River: Discharge, Turbidity, Erosion, and Sediments

Gary Loontjer
Mayer Lutheran High School
305 5th St. NE
Mayer, MN 55360
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In this field investigation, small groups of students will observe and measure characteristics of the South Crow River near Mayer, Minnesota. Data collection on these characteristics will include but not be limited to: speed of current at various places in the river, the amount of sediment (carrying capacity) of the water on this particular day, depth of water at various points across river (for depth profiles), erosion patterns, and river contours. Student groups will record observations and data in journals to aid in their group presentations at the close of this activity. Because this is a guided inquiry activity, the students will not be told exactly how to perform all data collection, but a supply of materials provided by school and individuals will be available for their use. One class period will be used prior to the field activity to share needed information and several class periods will be used following the field activity for the students to prepare their presentations.

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Learning Goals

Learning Goals
1. Students will identify questions that can be answered through a field investigation and which cannot.
2. Students will distinguish between observations and inferences.
3. Students will design necessary techniques and equipment for data collection.
4. Students will present and explain their data and findings.

The design phase of this activity will involve critical thinking skills. Data analysis will be used in preparation of their presentation.
This field investigation along with pre- and post-investigation class periods will allow the students to gain practice in the following skills: making observations, journaling, experiment design, equipment design, data collection, and data analysis.
Some key vocabulary words include: velocity, turbidity, discharge, erosion, profile, meander.

Context for Use

This field investigation is designed for (24) 9th grade earth science students to put a little excitement into this aspect of the curriculum and to allow students to see earth processes in their own backyard (so to speak). Students will be placed into same sex groups of 4-5. Much of the design of the data collection techniques will be left up to the students.
This activity is planned for a 1/2 day. One class will perform this activity in the fall and the other class in the spring. Pre- and post-investigation activities will take an additional 4 days of class time.
A supply of generic measuring devices and misc. lab equipment will be available. This would include: stopwatches, metersticks, tape measures, ping pong balls, wood matches, weights, rope, and other material students bring from home. Special core sampling tubes will be available for students to collect core samples at various points along the river.
Day 1 Introduce activity, explain the characteristics that we want to measure, allow time for student group work to plan how they will perform the activity.
Day 2 Do the field investigation
Day 3 Group work for presentation
Day 4 More group work time or early presentations
Day 5 Begin class presentations of data

This field investigation will follow class presentations on weathering, specifically that of moving water. Other topics covered prior to the investigation will include the formation of sediments and their possible sources. Most of the measuring skills should have been mastered prior to this activity.

Subject: Geoscience:Hydrology:Surface Water
Resource Type: Activities:Classroom Activity, Virtual Field Trip, Field Activity, Lab Activity
Special Interest: Field-Based Teaching and Learning
Grade Level: High School (9-12)
Theme: Teach the Earth:Enhancing your Teaching:Teaching in the Field, Teach the Earth:Course Topics:Hydrology/Hydrogeology, Teach the Earth:Teaching Topics:Water

Description and Teaching Materials

On the day(s) prior to the field investigation I will have instructed the students as to the characteristics of the South Crow River that we want to observe and measure. These characteristics would include: water velocity, water depth, discharge rate, amount of sediment in the water, the profile of the river at the point of observation, types of sediment layers present at the river.

The class would then be divided into the study groups and each group will be told to devise a method of measuring the data for each characteristic.

As mentioned earlier, there will be a supply of miscellaneous equipment available for the students to examine, adapt, and use on the day of the investigation. They may also bring supplies from home. Tubes for collecting sediment cores will be provided each group.

Students will also be instucted on the safety measures that will be taken while at the river and to bring a second set of clothes in case of "accidents". Proper footwear will be stressed.

Upon return to the classroom following the investigation, a place will be made available for core samples and water samples for sediment studies.

The following days will allow students to draw profiles of the river using depth measurement and to draw profiles of the sediment core samples. They will evaporate water from containers to determine amount of sediment in water. Given class data they will graph amount of sediment and stream velocity vs depth.

Student presentations will include pictures of the area (digital cameras), explanations about stream velocity vs depth, sediment carrying capacity of the river on the date of observations, water depth, discharge rate, etc.

The data collected in the fall will be compared to that collected in the spring by the second group.

Teaching Notes and Tips

This activity has never been done at this school. I am somewhat concerned about the safety aspects of this investigation because some of our measurements will be done from a bridge over the river. It will be interesting to see how 9th graders react to this. I hope that the second set of clothes is not necessary but wet feet will be a necessity. Most of our clean-up will have to take place before returning on the bus since the bus needs to be returned clean. I am sure there will be changes prior to the spring trip. I may have planned more activities than we can get accomplished in the 1/2 day.


The students will be told the required items for their group presentation to the class (profiles, charts, graphs, pictures, calculations). Since some of this will be using class data, there will be some redundancy but this is not a concern of mine. All need to complete the activities. A group score will be given on the completeness and creativity of the presentation. I would like them to be multimedia (Powerpoint). Vocabulary and important concepts will be assessed via a written test at the end of the unit of study.


9-12.I.B.1 Scientific Inquiry
9-12.I.B.3 Data Analysis
9-12.I.B.4 Experimental Error
9-12.III.A.5 Earth Structure and Processes
9-12.III.B.2 Wave/Water energy

References and Resources