Materials:
CBL system
TI-83 Plus graphing calculator
CHEMBIO program
Calculator-to-CBL link cable
Texas Instruments AC 9201 adapter (or use batteries)
Vernier Flow Rate Sensor
Measuring tape (15 meter or 50 feet)
Meter stick
Testing Procedure:
1. Within a 50-meter stretch of the stream, pick 2 sites that are far apart
as possible and are representative of the stream as a whole.
Avoid sites with bends or breaks in the stream caused by rocks or sandbars.
Try to choose a site where some flow can be observed
It is not necessary for both sites to be the same.
One site can have a swift flow similar to that found near a riffle.
The second site can have a moderate or slow flow like that found after a pool
2. At each site, take a cross-section of the stream and measure its width (meters).
3. Divide the total width into 6 equally spaced sections.
4. Measure the depth (meters) at each of the 7 dividing sections starting from
either end of the shore where the initial and final depth = 0 meters.
5. Record the measurements.
6. Measure the distance out from the shore of each of the 7 dividing sections
starting from either end of the shore where the initial distance = 0 meters.
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SITE #1
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DISTANCE (m)
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DEPTH (m)
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1
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0
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0
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2
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|
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3
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|
|
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4
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|
|
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5
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|
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6
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|
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7
|
|
0
|
|
SITE #2
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DISTANCE (m)
|
DEPTH (m)
|
|
1
|
0
|
0
|
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2
|
|
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3
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|
|
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4
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5
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6
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7
|
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0
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7. Use the link cable to connect the CBL System to the TI Graphing Calculator.
8. Connect the Flow Rate Sensor to Channel 1 of the CBL System.
9. Turn on the CBL unit and the calculator.
10. Press APPS and select CHEMBIO program.
11. Select SET UP PROBES from the MAIN MENU.
12. Enter "1" as the number of probes.
13. Select FLOW RATE from the SELECT PROBE menu (this will require selecting
MORE PROBES several times first).
14. Enter "1" as the channel number.
15. Select M/S from the FLOW RATE UNITS menu.
16. Select COLLECT DATA from the MAIN MENU.
17. Select SINGLE POINT from the DATA COLLECTION menu.
18. Place the Flow Rate Sensor at the same points the depth measurements were
made.
Since points 1 and 7 are on the shore edge where there is no flow, skip these
points and perform flow measurements at the remaining five points.
19. Submerge the impeller of the Flow Rate Sensor to about 40% of the depth
measured at each section.
If the section is shallow enough, use the plastic risers that are included with
the flow rate sensor to support the sensor on the stream bed. The risers make
it easier to keep the impeller of the sensor in the same spot and oriented in
the same direction.
20. Point the impeller of the sensor upstream and directly into the flow.
21. Press ENTER to begin sampling. Hold the sensor in place for 25 seconds while
data are being collected.
22. Once data collection is finished, the flow rate will be displayed on the
calculator screen. Record the reading on the Data & Calculations sheet.
23. Press ENTER and select YES from the REPEAT MENU.
24. Move the Flow Rate Sensor to the next section of the stream.
25. Repeat Step 18-24 for each of the remaining four sections.
26. When the flow velocity at all five sections has been measured, select NO
from the REPEAT MENU.
27. Exit the CHEMBIO program by selecting QUIT from the MAIN MENU.
28. Repeat Steps 1 – 27 for the cross section at Site 2.
29. To view the data lists, press STAT to display the EDIT menu, and select
Edit.
30. Clear any previous data from lists L1 and L 2 — move the cursor to
the L1 heading and press CLEAR, then ENTER. Do the same for the L 2 list.
31. Enter the distance measurements from the Data & Calculations sheet into
list L1.
32. Enter the corresponding depth measurements from the Data & Calculations
sheet into list L2.
33. Run the CMBINTEG program to calculate the cross-sectional area of Site 1.
Record the calculated area on the Data & Calculations sheet.
34. Repeat Steps 29 – 33 for Site 2.
