Well, all those values sound reasonable, so let’s put a bit of math to it:
Total irrigation water at once = 0.17 x 25.59 x 0.5 = 2.175"
Divide inches of water by Nozzle Inches per Hour = 2.175 / 0.5 = 4.35 hours.
90% Efficiency will increase this by 1 / (0.4 + 0.6 x 0.9) = 1.063, so 1.063 x 4.35 = 4.63 hours = 4 hours 38 minutes (close to the listed 4:23, but no cigar). Still, close.
The only things possibly in doubt would be root depth (can vary with size of trees), and Nozzle Inches per Hour (I’ll let tmcgahey comment on that).
Boy, if you are truly only putting down 2 gph on a tree, that run time is WAAAAAAAAY low. I have most of my trees with anywhere from 4-8 2gph emitters (8-16 gallons total per hour), and my zones run for over 4h.
Depending on the canopy size of the tree, you should be putting down 20+ gallons just to wet the root zone. That would mean you should be running that zone for 10 hours. Might need to do a bit more investigating on what you have so that we can better dial things in.
They are smaller trees - like 4 or 5 ft canopy (20 gal). And I might be way off on the guess for # of emitters since they are drip-lines. Let’s say the trees each get 4 gph from the emitters, so maybe the 4:38 in the schedule is not that far off from the target of 5 hrs. If I want to get a bit more watering time, what would I change? Reduce the Nozzle Inches per Hour I assume…
It seems overly complicated for drip setup — “Tree”, the table above plus the emitter gph should be all that is needed (besides soil type). Why do they make me look at this in inches/hour and square feet?
A just read that a small tree requires about 20 gallons of water per 1" of trunk per week. So that would give you your 4 gph x 5 hours. As you say, seems about right. And trees can be watered once a week, or even less, without a problem.
Yes, lowering the Nozzle Inches per Hour increases watering time.
IMHO, way too complex. But the alternative, asking you how many trees, what size emitter and how many on each and every tree, etc. is even more complex. tmcgahey will recommend a spreadsheet to give the proper values, but I found the spreadsheet more complex than my own calculations (of course I’m an engineer, so love calculations /and/ spreadsheets), so I made up my own.
In your case, if you like the 5 hour figure, I would either 1) Play with the Nozzle In/hr figure until you get 5 hours with Flex Daily, or 2) Use a Fixed schedule for watering once a week, set it for 5 hours, and turn on Seasonal Shift. That will give you more water in warm weather, less in cooler weather.
Square feet isn’t needed for this purpose. Leave it blank if you want. Like I said, all that does is calculate the water uses/saved in gallons if you choose to have Rachio show you that on the home page.
There is an excel file created by a member that really makes it stupid simple to calculate. At one point, Rachio was going to use it in their documentation. To help you calculate it, all I need is the number from the moisture chart showing how much water Rachio wants to put down, in inches for that tree zone.
Thanks to both of you @tmcgahey, @rraisley and @Alturia for the great help. I/we still don’t know how Rachio got all confused on this, but I am good now with a fresh schedule.
Here is the details of the excel file that a member made. This is just an example using my flex daily watering requirements, along with your GPH per plant (4 gph) and average canopy size (requiring 22 gallons per watering). If you can get me the value from your system on what that zone wants to water on a given cycle, you can plug that adjust the custom nozzle PR. For this example, you would want to set your nozzle inches per hour to .37". While not required, you could calculate your area from this chart also…
