6
4.
Calculating Stream Cross section
•
Create a graph of stream depth
vs
. distance from the shore.
•
Integrate the data. The integral value will give you the cross-sectional area of the
stream.
5.
Determining Discharge
•
Calculate the average velocity for each site.
•
To calculate the discharge or stream flow, multiply the average stream velocity
by the cross-sectional area. Repeat for Site 2.
Additional tips
1.
The plastic risers that come with the Flow rate
sensor can be very helpful in keeping the
sensor at the same orientation while taking
measurements. When using the risers, simply
place the bottom of the sensor rod against the
stream bottom. If you are unsure which riser to
use, start with the medium riser first and gauge
the depth from there.
2.
When students are selecting sites to take flow
measurements, they should choose a site where
the stream is not split by rocks, partially
submerged obstructions, or sand bars.
3.
The impeller of the Flow rate sensor should always be pointing into the flow
when measurements are being made. Students need to stand on the shore when
taking measurements close to the shore, or stand as far downstream as possible
from the sensor when placing the sensor in deeper water.
4.
Because stream flow is easily affected by weather conditions, it is important that
good notes concerning date, time, and weather be taken whenever flow
measurements are made.
