Hi, my name is Laura Flight and I am a Hydrologic Technician in the Augusta, Maine Office.
This screencast video will show how to do a midsection discharge measurement in SWAMI
with a mechanical current meter, such as a Price AA or pygmy meter.
From the "Site Visit Tasks" screen select the "Discharge Measurement" button in the
task list.
Next select "New Channel."
Give the channel a relevant name, such as "main", or "left" or "right" by typing in
the field next to "Name."
This is especially important if you will be doing a multi-channel measurement.
From the pick-list next to "Qm Method" select "Midsection" for this midsection measurement
method.
Once the midsection method is selected, other measurement properties appear.
Under "Deployment Method", select how the midsection measurement is going to be made.
In this case, let's do a wading measurement.
Then select the "Velocity Method" from the pick-list.
In this screen cast video, we are covering AA or pygmy meters so let's choose a Price
AA velocity method.
From the next pick-list for "Meter", I will select the serial number of the AA meter I
am using.
This list comes from SiteVisit and should be specific to your Water Science Center or
Field Office.
From the "Suspension" pick-list, select "Top-setting wading rod" for the USGS top setting wading
rod.
To proceed, we must inspect our meter.
If a spin test is not done, you must indicate that you have inspected your meter by selecting
the check box next to "Meter Inspected" to continue.
Select "Measure" to start recording mid-section measurement information.
It is recommended that this not be selected until you are actually ready to measure (have
your tagline strung, meter gear assembled) as this will later be tagged as the measurement's
start time.
From the "Midsection Measurement" screen, select "New Section" in the upper right.
The next screen is where information for each individual vertical observation of this midsection
measurement will be added.
We will start with the "Distance" box, where we will enter our edge distance on the tagline
for our first section.
Enter the total depth, which often on the edge is 0.
When this is the case, the revolutions and time at the 0.6 depth will be automatically
be populated at 0 and 40.
Then select "Done" as we have finished entering information for our first vertical.
Back at the "Midsection Measurement" screen, select "New Section" to enter information
about the next vertical, starting with the distance and total depth.
The width will be calculated automatically based on the defined section distances.
After a few sections if you are doing even or patterned stationing between verticals,
SWAMI will recognize this and auto-populate the distance.
However, it can always be changed and should be if the amount of discharge being measured
in each section is changing in order to adequately profile the cross section.
In this section, we have a depth of 1.52 feet and since we are using a AA meter, the 0.6
velocity observation row in the middle of the screen is highlighted green indicating
we should take our velocity measurement at 0.6 of the total depth.
Next to the 0.6 is the "Rod Set" column; this is the position you set a USGS wading rod
using the scale on the handle so that the meter is at 0.6 of the depth.
After taking your velocity observation with the AA meter, in the 0.6 row enter the total
counts in the "Rev" box and the amount of time in the "Time" box.
Velocity information will now be populated in SWAMI.
Note: You do not need to stop on a "defined" count such as those listed on the meter rating
tables (7, 10, 15, 20 etc.); SWAMI will calculate the velocity based on the meter equation.
Hit "Done" when you have completed this measurement section or vertical.
You will notice that each time you are finished adding a section you return to the "Midsection
Measurement" screen where you can review the data you have collected so far.
I will add another section and enter the distance and total depth.
At this section our total depth is 2.65 feet, so now the 0.2 and 0.8 velocity locations
are highlighted since we are using a AA meter and the depth is greater than 2.50 feet.
Measure the velocity for the 0.2 and 0.8 depths (the order does not matter) and enter the
values after each.
You can also add a 0.6 reading if desired; SWAMI will calculate the average velocity
appropriately.
In addition, SWAMI will warn you if "an irregular velocity profile is indicated" and suggest
a 0.6 reading be obtained.
Select done when you are done with that vertical.
Let's go to the next section.
At this section we have an angle to our flow.
To add this, in the box in the upper left under "Coef/%" where it lists "1.00", enter
the angle coefficient such as 0.99.
Select done when finished.
I will again add another section.
Let's say we have finished our measurement at the opposite edge and there is vertical
wall that does not have a depth of zero.
Enter the depth, then in the "Coef/%" box, type the % of the velocity of the previous
section to be used as the velocity for this edge section.
For instance, enter 25% if the velocity at the edge section is estimated to be 25% of
the velocity measured in the previous section.
Then in the upper left under "Pier/Est" select "EstP" to estimate the velocity based on the
"P"revious section.
"EstN" would estimate based on the "N"ext section.
"EstM" is for a "M"anual estimate.
Then select done.
Overall, here are some other things to point out about the vertical or section entry form.
If you click the "Note" button near the upper right, you can add a text comment such as
"rock upstream in section" or "pivot slipped" that will be tagged with that section.
This feature currently only works on a PDA.
Above the "Note" in the upper right of this screen, SWAMI cycles through the battery status
of the device you are using (if known), the discharge calculated in the previous section
(to help you stay under 5% in each section), the number of sections you have taken so far
in the measurement, and the distance along the tagline of your previous section.
This is helpful information as you make a discharge measurement.
To insert a section or vertical, at the "Midsection Measurement" screen that lists the sections
taken, right click on a row then select "insert before" to insert a vertical prior to the
selected one, or "insert after" to insert a section subsequent to the selected one.
Then enter the distance, depth, and velocity as appropriate.
To delete a section or vertical, at the "Midsection Measurement" screen that lists the sections
taken, right click on the row to be deleted, and select "Delete."
A warning box pops up to ensure the desired action is to delete this section.
To edit a section or vertical, at the "Midsection Measurement" screen that lists the sections
taken, right click on the row to be edited, and select "Edit."
The information for that vertical is now displayed.
Type in any of the entry boxes to make an edit.
Then select "Done."
Although the time for each vertical is not displayed at the "Midsection Measurement"
screen, it is displayed when the SWAMI file is displayed with a style sheet.
An edited section will be time tagged with the time of the edit.
We have now finished taking verticals for our midsection discharge measurement.
At the "Midsection Measurement" screen, you will notice summary information here such
as the total number of sections, average velocity, total width, total area, and total discharge.
Since we are done with our measurement, I will select "Done."
A dialogue box asks you if you are sure, select Yes.
If you have questions on the process of performing a mid-section Price AA or pygmy measurement
in SWAMI, please contact the SWAMI help group at the e-mail address shown, or visit the
FCIS website at the address shown.