Title: Stream Profiles and Their Relationship to Meanders

Title: Stream Profiles and their Relationship to Meanders

Class: Environmental Biology

Grade: 11-12

Timeframe: 1-2 days

Knowledge Gap Topic / Direction of stream flow from smaller tributaries into larger ones, stream order and streams becoming more meandering as their gradient decreases.
Subject Matter/
Key Vocabulary / stream flow, elevation, stream profiles, stream gradients, drainage patterns
Essential Question/
Over-Arching Concept/
Key Understanding / How does topography/elevation/gravity determine the flow/direction of stream?
Curriculum Connections
·  OGT standards
·  Local standards / Earth Science 9-10: B, E; 11-12: B, C
Instructional Objectives / O1) Students will use Google Earth maps to calculate stream profiles and meanders of several different rivers to derive the basic relationship between profile, number of meanders, and approximate age of river
O2) Students will relate meandering to stream flow, showing that healthy rivers tend to be steep at the beginning, then gradually having more and more turns/meanders as it approaches its mouth. O3) This relationship will be related to urban areas straightening streams and its effects on riparian zones and stream health.
O4) Students will also be able to realize that small tributaries flow into larger sections of rivers and that direction of stream flow can be determined by analyzing the shape of the rivers and its tributaries
Materials / 1) Computer(s) with Google Earth and knowledge of tools to find elevation and waypoints
2) Stream Characteristic Worksheet
3) Excel (or other spreadsheet) to do calculations of stream gradients
Introduction
·  focus event
·  varies with teacher / Set up two different river pictures from Google Earth; one a fairly young, straight stream with lots of rapids and white water, and another with many meanders and slower moving. Ask students to identify the observed differences. Demonstrate how much the river drops using Google Earth. Then we start the lab.
Development
·  major parts of unit/ lesson / 1) Examine 6-8 streams from around the world on Google Earth for elevations at various points and distances.
2) Calculate both stream gradients and count numbers of meanders
3) Graph numbers of meanders vs. gradients to discover relationship between the two
Rigor/Relevance Quadrant(s)
·  link to rigor/relevance document / A: Must use terms correctly … source, headwaters, mouth, watershed, sedimentation, meander, tributary, gradient, profile.
B: Correctly calculate gradients of various streams
C: Plot gradients vs. meanders to establish relationship
D: Students establish relationships between steepness of streams and meanders and come up with a general rule regarding age of streams based on meandering
Product/Artifacts/Student Evidence of Understanding / Students produce spreadsheet and graphs relating gradients of streams and meanders.
Students generate a general rule regarding age of streams vs. meandering.
Accommodations
·  plan B
·  differentiated instruction / You may have to divide teams up so that at least one member is comfortable with math. Some students just “freaked out” when they had to calculate a profile … they weren’t hard, but students were fearful. Those who were better at math seemed to have an easier time making the connections from the map and meanders to the math.
Formative Assessment/Feedback
·  measure of progress / Have students check initial gradients calculated to be sure they are correct.
Check graphs of gradients vs. meanders to be sure students are graphing correctly
Final Evaluation
·  project rubric
·  oral or paper quiz/test
·  portfolio / Give students two new streams where they calculate gradients and meanders. Estimate the age of the stream based on their collected data and previous data from the lab
Teacher Reflection
·  complete after lesson / My kids really “plugged” away at this lab … because it was using Google maps, it was engaging, but it was very challenging for most students. I think an easy profile based on some simple data and a graph might be needed first before this activity.

Designers/Email: ()

Additional Comments: An activity to provide a practical use of graphing to come up with a general rule. This lab helps students relate gradients and meanders, thus showing them that as a stream erodes over time, meanders increase, giving a general way to determine age of streams.

This lab is very challenging for the average environmental botany student. Good students find it challenging, poor students must be given help. However, it is good to stretch them.

Stream Characteristics

Name______

Date______

Part 1: Using Google Earth, find the following rivers. To determine the distance, go to tools > measure > path. Follow a path along the river are carefully as you can. After noting the distance, clear the path and make a line directly from the beginning to the end to determine the straight line distance.

1.  Mississippi River (30o 26’N, 91o 11’W), from the bridge in Baton Rouge (elevation 10 ft) south to the island across from a pier at (30o 18’N, 91o 13’W) (elevation 3 ft)

1. River distance _____miles
2. Straight line distance ______miles
3. Describe the river as one of the following:
4. Fairly straight
5. Contains some meanders
6. Has many meanders

2.  Delaware River from the Delaware Water Gap (40o 58’N, 75o O8’W), (295 ft) South to the bridge at Phillipsburg (40o 41’N, 75o 12’W)

1. Distance of river ______
2. Elevation at Phillipsburg bridge______
3. Straight line distance ______
4. Description of river
5. Fairly straight
6. Some meanders
7. Many meanders

3.  San Juan River near Shiprock- Go from Farmington, (36o 44’N, 108o 15’W ), (elevation 5211 ft.) to Shiprock, NM (36o 46’N, 108o 41’W), (elevation 4892 ft) to

1. Distance of river ______
2. Straight line distance ______
3. Description of river
4. Fairly straight
5. Some meanders
6. Many meanders

Part 2:

1. The straightness of a river is called its sinuosity. It can be calculated by dividing the length of the channel in a section of a river with the straight-line distance of the same section of the river (as the crow flies). Access the spreadsheet called River Characteristics Exercise from the Honors Geology Website or course materials. Notice that it contains data from other rivers as well.
2. Write in your descriptions of the shape of the river in column D.
3. Put the formula (=F3/G3) in row I3 to obtain the sinuosity of the rivers. A meandering stream would have a sinuosity of 1.5 or greater. Is the Platte River a meandering stream?______Fill in the rest of the column by highlighting cell I3, dragging the cursor down to the bottom of the column and hitting control d. (fill down command).
4. Did the sinuosity numbers agree with your description of the shape of the rivers?

1. Gradient is change in elevation per mile of distance (literally the rise over run). Calculate the elevation change for each river by putting the formula =B3-C3 into column E and fill the formula down as before.

1. Make a graph (x-y scatter graph) of the relationship between sinuosity of a river and its gradient . Which is the independent variable?

1. Describe in words the result of the graph. Be specific. Is the relationship linear?

1. Print the graph and add a trendline by hand.

Part 3: Testing your hypothesis

1. Now that you have created a graph that predicts the relationship between gradient and sinuosity, find out if it can predict the sinuosity of another river. Go to Buellton, CA. Find the Santa Ynez River (34o 36’N, 120o 11’W) and follow it to the ocean. Note the elevation______, river distance______, straight line distance______.
2. Calculate the gradient of the Santa Ynez River from Buellton to the ocean ______ft/mile
3. Using the graph that you created, predict the sinuosity of the Santa Ynez River______
4. Calculate the sinuosity by measuring the distance and the straight line distance and add them to your spreadsheet. ______By hand, plot and label the data point. Was your prediction correct? Explain why or why not.

1. Go to Mexican Hat, AZ. Go northwest and follow 316 to the end. Start just West of the end of 316 on the San Juan River (elevation 3951 ft) (37o 10’ 23”N, 109o 55’, 53”W) . Follow the river to the far side of the Mendenhall Loop (37o 10’ 54”N, 109o 53’, 15”W) (elevation 4025). Determine the gradient and sinuosity and add it to your spreadsheet. Plot the data point. Does the San Juan River data fit the graph?______Explain what is unusual about this section of the San Juan River.

Hand in your data and your graph with this worksheet.

Designing Watershed-based Education and Extension Efforts through a Mental Models Research Approach

USDA-CSREES National Integrated Water Quality Program