Stream Discharge – Activity Mr. Distasio
Name ______per ______
Problem
A stream-gauging station measures the volume of water flowing past a certain location each second. A rain gauge provides data on the number of centimeters of rain falling per hour. Data for a sample 12-hour period is shown in the table on the back of this sheet.
What is the relationship between the amount of rainfall and stream discharge?
Materials
· 2 pencils of different colors
Hypothesis
Just by looking briefly at the data in the table and using any prior knowledge you may have, complete the following statement/hypothesis.
If the amount of rainfall during a specific period of time increases, then the volume of stream discharge will also ______during that same time period.
Procedure
1. On the attached graph, construct a line graph that compares the rainfall and stream discharge data. Notice that graph has two vertical axes and one horizontal axis. The rainfall in cm/h is on the left vertical axis and stream discharge in m3/s is on the right vertical axis. The horizontal axis shows the time.
2. Plot the data points for rainfall. Connect the points to produce a curve showing the amount of rainfall over time.
3. Use the other pencil to plot the data points for stream discharge. Connect the points to produce a second curve showing stream discharge over time.
Analysis
1. How much time passed between the heaviest rainfall and the greatest stream
discharge? ______
How do you explain the time difference? ______
______
2. How do the two curves compare in height? ______
Give reasons for the difference. ______
______
3. How do the curves compare in shape and steepness? ______
Give reasons for the differences. ______
4. Predict what the volume of stream discharge will be at 1:00 AM the following morning.
Explain your prediction. ______
______
Conclusion
What is the relationship between rainfall and steam discharge? ______
______
Data Table
Time / Rainfall(cm/h) / Stream
Discharge
(m3/s) / Time / Rainfall
(cm/h) / Stream
Discharge
(m3/s)
12:00 noon / 0 / 220 / 6:00 PM / 0.3 / 3400
1:00 PM / 2.0 / 290 / 7:00 PM / 0 / 2285
2:00 PM / 5.9 / 440 / 8:00 PM / 0 / 1420
3:00 PM / 6.2 / 830 / 9:00 PM / 0 / 1000
4:00 PM / 3.2 / 1400 / 10:00 PM / 0 / 950
5:00 PM / 1.0 / 2000 / 11:00 PM / 4.0 / 950
Graph Example
Time
Rainfall in cm/h
Stream discharge in m3/s