This is the raw data we got from the river:
The mins it took the tongue depressor to float from point a to b and the depth of the river on those days.
Using area x velocity, I need to calculate the discharge results for the following dates:
April 4 2:52 mins 1.55 meters
April 5 2:40 minutes 1.63meters
April 6 2:06minutes 1.7meters
April 11 1:17minutes 1.86meters
April 12 :59minutes 1.82meters
April 13 1:10minutes 1.8meters
How do I determine discharge?
Ms. Sue,
I coverted the minutes into seconds and here is what I got:
April 4 172
April 5 160
April 6 126
April 11 77
April 12 59
April 13 70
1.55/172 = 0.009 meters per second
To determine the discharge, you need to multiply the cross-sectional area of the river by the velocity. In this case, you have the velocity of the river (given by the time it took the tongue depressor to float from point A to point B) and the depth of the river for each date.
To calculate the area, you will need to measure the width of the river at point A and point B. You can average the width measurements to get a representative value for the cross-sectional width of the river. Then, multiply this width by the depth of the river to get the cross-sectional area (Width x Depth).
Next, you need to convert the minutes into hours for the velocity calculation. Divide the time in minutes by 60 to get the time in hours. Then, divide the cross-sectional area by the time in hours to calculate the discharge.
Let's calculate the discharge for one of the dates as an example. We'll use April 4th:
April 4th:
Time: 2 minutes and 52 seconds = 2.87 minutes = 2.87/60 = 0.048 hours (approximately)
Depth: 1.55 meters
Now, let's assume the width of the river at point A and point B is 5 meters. So, the average width is 5 meters.
Cross-sectional area (A) = Width x Depth = 5 meters x 1.55 meters = 7.75 square meters
Discharge (Q) = Area x Velocity = 7.75 square meters x 0.048 hours = 0.372 cubic meters per hour
Repeat the same calculations for the remaining dates to determine their respective discharges.