So you have two pipes carrying storm water and they feed into a third pipe. You have instruments recording the flow in the third pipe and one of the feed pipes (we’ll say pipe 1). For the moment we will ignore gains and losses, as these are outside the arena of this demonstration.
Thus we will proceed on the assumption that the “sum” of the two pipes feeding the third is the resulting flow from the two source pipes. We have instruments watching the “third” pipe and one of the two “source” pipes (Pipe 1). Given all of the assumptions we’ve stated, the difference between the sum (flow in Pipe 3) and that coming in via Pipe 1, has to be flow of Pipe 2. Trivial until someone actually wants a report printed, or even worse, a graph that includes the sum and both of the sources. Now you are going to have to fire up a spreadsheet, import some numbers, and figure out how to plot it all.
Or you can quickly take advantage of FlowWorks Advanced Calculation Engine’s (FACE) ability to work with multiple sites.
Log into FlowWorks. Click (or hover over) the management button in the FlowWorks menu bar and click on “FACE: Configure Sites” in the list of options that will appear. Click on the dropdown arrow in the select site box and scroll to one of the two sites at which you have instruments… we’ll say the “Pipe 3” Site.
Click on the “Create New Channel” command. We’ll name this channel something that indicates the storm facility, we’ll call it “Pipe 2” and give it your standard flow units. Leave the channel type “Calculated” and leave the check mark in the “Visible” box because we want to see and plot the virtual data with which we will “fill” this channel. Click “Save” and we’re done here.
FlowWorks will take us back to the site’s channel screen and we will click the drop down arrow in the select calculated channel box and scroll until we can select the calculated channel we’ve named “Pipe 2”. Then click “View Calculation.”
Since no calculation has been created, we are prompted to create one. Click “Create”.
Let’s call this calculation the name of the phantom site we’re creating – “Pipe 2” and in the description we’ll put “Computing the flow contributed to Pipe 3 by Pipe 2.” Leave “Formula” in the calculation type and ignore the start and end date options because we want this channel to be filled with data points for the entire data stream we have available.
So now we’re at the calculation source selections…
Source 1 is going to be the site we’re calling “Pipe 3”, click the dropdown arrow in the site box and scroll to and click on that site. Next, click on the dropdown arrow in the channel box and select the flow channel for that site. We could leave the variable name as “A”, but let’s think of this as the flow from Pipe 1 (A) plus the flow from Pipe 2 (B) equals the SUM (in Pipe 3), so click on the dropdown arrow in the variable box and then click on the “S”.
You will then click the “Add” button as we need a second source.
In Source 2, we are going to use site 1 (Pipe 1), so click on the dropdown arrow in the site box and click on Site 1 (Pipe 1). In the Channel box, click on the dropdown arrow and then click on the flow channel for that site. In the variable name box, select “B”.
If S = A + B, then B (the flow from the phantom site) will be equal to S – A.
We are creating the calculation that will produce the data points to fill the flow channel for this phantom site, and we do this by going to the equation box and entering in… S – A.
You can now go to graphing and select Site 1’s flow channel. Then select site 3’s phantom channel (Pipe 2) and site 3’s flow channel. Plot those for any time period you desire (you might have to play around a bit with the scaling) and you will see that you have two sources and one sum.
While trivial (as we warned you), this demonstrates how you can use FACE with measurements from more than one site. You can hand off this report or graph without the need to explain yet again how come you have measurements from Pipe 1 and Pipe 3 but not Pipe 2. We won’t tell them how you did it if you don’t.