Three years and still no Gallons per Hour?

Archive
21

@Linn, my point exactly. Rachio is designed as a lawn irrigation system which it seems to do well. It is not designed to do emitters. It could, if Rachio would put the effort into it, but as of yet they seem uninterested. I am mystified why they continue to give their customers complex formulae to work out manually when they could easily put it into their software. After all, computers are build around math.

That being said, I have talked to several horticulturalists who have been unanimous that Rachio’s conversion formula is completely worthless because among other things, it includes area. To a person, that have all said that it is obvious that Rachio has a sprinkler paradigm. It is certainly not designed to work in the dryer South West regions.

22

What I mean is that all else being set properly, changing the area parameter won’t change your watering duration or frequency. That entry in the app. doesn’t factor into the water delivery equations. It only factors into the estimate of how much water that you used.

I agree with you completely. It’s why I don’t agree with the 1ft x 1ft area assumption that is often given as a workaround.

I disagree on this point. It’s not useless at all, but it does require a fairly complex set of workarounds to get set up properly. I pointed them out to you earlier in this thread. I have set my trees and shrubs based on those workarounds and I see the proper amount of water delivered, and the frequency of the associated watering changes accordingly with changes in climate. In fact, I’ve found it more stable than my lawn which I’m having more trouble dialing in. However, I do think more effort should be spent by Rachio such that those workarounds aren’t necessary. They’re quite a bit more complicated than the average user is willing to spend time on.

Maybe it’s a nomenclature thing, but I think the reality is that the system is based on commercial agricultural irrigation techniques, which includes overhead spray systems and grid-based emitters. Grid based emitter systems are much more uniform and can more easily and accurately be converted to per-inch water delivery, which is what those agricultural watering equations are based on.

Ultimately, you make great points and I think it’s important for Rachio to address, and I do wonder if they realize how much of their potential market this affects.

23

Frankly I found it to be quite the PITA to have to figure out what my emitters were putting out even though I knew they were 2 gallon emitters.

24

Could you provide some documentation that states volume is superfolous?

1 x 1 square foot is multiplied by root depth to compute volume.

Area in zone is only used for estimates.

I have been racking my brain to propes something to aid in drip irrigation but can’t come up with anything useful. Would like to hear how you think it should work…

25

I don’t think @Boris is suggesting that volume is superfluous, but rather that area is in this case. If you look at the Water It Wisely site (http://wateruseitwisely.com/100-ways-to-conserve/landscape-watering-guide/plant/) the metric used to deliver water to a shrub based on single point emitters is in gallons. For water usage we also only care about gallons. The area is then superfluous. Of course the irrigation equation uses depth, so the area is needed only as a means to get back to a volume for the usage calculation.

26

a drip system is a system that is meant to be tweaked by hardware adjustments, so by definition, you should set your drip to one/two hour(s) and augment water applied by adding/removing emitters where needed as it is a heterogeneous system.

you would do this with a fixed schedule. now if you want to use a flex schedule, aka tracking moisture loss, volume becomes an underpinning of the algorithm. without volume you have no reference point.

at risk of sounding callous, this statement is false. area is taken into account as they are very explicit as the diameter of the drip ring. its just casually mentioned as the canopy diameter. so to continue on this thread, a tree with 1 foot diameter needs 1.5 gallons an hour, this is roughly 5 square feet so that is your area to plug into the formula with 1 gallon an hour emitter, now we can compute a pr. i hope you can see how this becomes a moving target.

so ill take the pepsi challenge any day with the horticulturalist that says area is not important…they do not either understand what they are saying or have just oversimplified it in their head.

the real question that nobody answers is, what does gallons an hour mean without area? it says nothing about how spread out that water will be, thus we can make no determination as to how deep the water has traveled.

i can put a 1 gallon an hour emitter on a tree 10 feet away and run my irrigation for 10 hours. the tree is still going to burn up as the water is not being distributed evenly over the root canopy and depending on the soil, will just spread out very shallow and transpire away in a day.

its an extremely hard problem to solve and everybody keeps over simplifying the situation.

just one last example on how just gallons an hour is misleading. if i put 10 1 gallon an hour emitters in a ring that is 5 foot in diameter i will end up watering to a depth of .07 inches. if i put 2 5 gallon an hour emitters on a ring 2 foot in diameter i end up watering to a depth of .2 inches. same gallons an hour, much different depth of watering thus much quicker loss of water.

if someone wants simple, then fire up a fixed for one hour, add up all the emitters gph, divide by number of emitters, plug into pr formula, create a custom head, rinse repeat every time you change your system.

27

@plainsane. I see some of your points, but at least it out here in the desert there are some realities that make the current implementation less practical than it should be. I’ve lived out here for 22 years and have yet to see a true drip ring. I have multiple emitters on my tree spaced roughly evenly apart, but it’s by no means heterogeneous. I’ve had 5 irrigation “remodels”, and none of the companies put in rings. Now that I know better I would ask for them, but I’m sure over 90% of the market doesn’t have them and likely won’t for decades to come.

Everyone out here understand GPH heads. They have no clue how to translate to in/hr when they reach the nozzle page. Giving them an option for GPH gets them way closer to something they can work with when they download the app. Don’t get me wrong, I see your points about the area mattering as one should have a proper drip ring, making in/hr more meaningful. Given that they don’t it gets even more confusing to have to translate to another number. Even if they did it is an extra and not so obvious step to translate to in/hr. The Water It Wisely approach has worked for myself and others it here, so it can’t be all that bad (again, I agree that there are some assumptions to the simplified approach!)

Saying that a fixed schedule should be set assumes that those users don’t need the benefit of the evapotranspiration throttling. I have my non-heterogeneous drips on Flex and absolutely loved seeing the frequency drop from 8 days to 5 when temps shot up from 85F to 118F.

Ultimately, as you point out, it’s a difficult problem. I think it then becomes a discussion of what’s easier for the majority of end users facing that problem.

Thanks for the interchange and value added points…

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28

@plainsane, I think you are ignoring the basic point that I and others have been trying to make. and that is that in the calculation that Rachio uses, the surface area factor is completely superfluous for a single point emitter system. Volume UNDERGROUND is not the same a surface area, as you point out later.

I think that you have unintentionally highlighted the ridiculousness of the Rachio expecting it’s customers to be experts in both botany and mathematics. While you may be trying to water an oak tree with a drip system (not terribly efficient, I think) most of us are watering single shrubs or small bushes, flowering annuals and that sort. Why would I put a drip ring on a yarrow or a rock rose? A single pressure compensating emitter should do just fine. I do appreciate your example but it really underscores how completely lacking in support for single point emitter systems Rachio’s software is. An inch/hour calculation would not change the situation.

Your last point hit mine on the head - Why spend $250 on Rachio’s broken promises and deaf ears when you could get a much less expensive system with actual support that works better and does what we want? I would hope that SOMEONE at Rachio is listening but I’m not holding my breath.

And just for the record, two of the gentlemen I talked to had doctorates - one in Horticultural Engineering - so I do trust what they say when it comes to plants and numbers. And I actually do like Pepsi much better than Coke. : )

29

can i ask a question? what value would you put in for gallons per hour?

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I understand ppl think in gallons per hour. The only point I’m trying to make is that is half the picture. If you are planning a for trip, who cares if you car gets 20 miles to the gallon. That tells half the story, you also need to know how many gallons you have left. Thus 3 dimensional volume.

But I’ll ask you, what value would you put in the gallons per hour setting for one of your zones.

31

@plainsane I have 1GPH heads for my shrubs and 2GPH heads for my trees. I have three 2 GPH heads per tree and would therefore set 6 GPH for trees. Shrubs are all single point with 1-GPH heads so that would be my entry.

The Water It Wisely site recommendation is 8 gallons for my shrubs and 30 for my trees. I their have 8 hr watering times for my shrubs and 5 hours for my trees, respectively. My shrubs water about every 5 days now. They had been going 1 day longer but were showing signs of distress on that final day so I notched up the crop coefficient.

When you tell me what I’m doing wrong adding heads to 30+ sights in 112F weather isn’t on the table. :wink:

32

I have been reading this thread with great interest. There have been a lot of good points made by everyone.

I had not read the Water It Wisely document as I originally thought it just pertained to the desert environment. After reading it, it is one of the best write ups I have seen for using drip emitters. And it turns out that I had kind of stumbled on the settings they recommend. Just by watching my annuals/perennials, I had discovered that I need to run my system about an hour a day during the really hot nasty days for them to look healthy. When it hasn’t run, I had a couple of new plantings reach the permanent wilt point. (IMHO, Rachio should point to this link in their support doc as it is such a good article to help us regular homeowners figure things out AND clarify that it is good info no matter where you live to get you going).

I also don’t want to use a fixed schedule, because I just strongly feel that using flex daily makes more sense, allowing the system to not have to water every day once the weather conditions get a little cooler.

Having done computer programming at one time in my career, I don’t see why the custom nozzle portion of the Rachio code couldn’t be front ended with a little code that lets you either choose GPH or inches/hour. It’s a relatively simple math equation that would make things simpler for users. The back end of the code could remain the same,

33

@Linn, agreed, this is a great resource and we’ll add it to the support doc for drip emitters.

While this feature request is still in our backlog, we have a new support tool (compliments of @lucasc) to help with calculating precip rate using GPH. To use, visit the link above, then follow these steps: Select US/Imperial units > Select Turf or Drip > Select Meter Measurement if Turf > Skim the meter instructions overview, select Continue > in the available fields, enter the following: GPH = Gallons Measured, 60 = Minutes Tested, and Square Footage of Zone = Area (you should see the screen below) if you’re entering GPH for drip emitters, use the value “1” for area

Let me know if this tool helps. We can refine it if there’s any confusion.

Best, Emil

1 Like
34

@emil It’s great to see that you guys are moving forward on these types of calculators to get people going! I have a couple of questions.

1 - I don’t see the Area when I get to the same screen that you show. What might I be doing differently ?

2 - Would you mind commenting on this post as related to the 1ft x 1ft area assumption ? Had I done that for my case I would have ended up with a PR much higher than necessary to get the recommended deep desert watering that is common here, and recommended by our local resources. It seems that the 1ft x 1ft assumption is good for heterogeneous systems with emitter grids and/or rings, but I don’t see the same application for single point shrubs, etc.

Thanks again, this work is great to see !!!

35

Hi @azdavidr,

I really appreciate your feedback. With drip lines - area is set to 1 for the calculation because drip lines have a higher pressure than your typical rotor/fixed spray head and do not cover much ground. Hence why this goes straight to a meter measurement test.

If there is a better way that you, @emil, and I can get together, I am happy to get make the changes needed.

36

@lucasc I see, the turf option has the area but drip doesn’t. That makes sense! As a side note, the drip calculation when choosing US measurements puts out PR in cm/in. I’m not sure that’s what you intend?

37

@Linn, the wizard and the custom nozzle articles are now linked together. See this article now

@azdavidr Good catch! It’s fixed now :cheers:

38

I’m not saying you are doing anything wrong. I’m just going through the thought expirement.

So if you had the gph box you would enter?

I’m assuming you would make multiple entries for a single zone and the software does its intergalactic business and computes a mythical number (you didn’t provide enough info) of 60 gallons an hour.

Are saying that you would want to configure flex to apply 120 gallons of water this a 2 hour run time?

39

Here is my exact process from Water Use It Wisely. The steps below correspond to the same steps in the website.

Step 1: I picked the following average canopy sizes for my larger shrubs and trees, and found the appropriate gallon recommendation

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Step 2: Take note of my GPH per shrub and tree as directed by the site. In my case it was one, 1 GPH emitter per shrub, and three 2 GPH emitters per tree. Here’s what they state for step 2.

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Step 3a: Use the information from steps #1 & #2 for the entries in the calculator they have in this step. Hit ‘Calculate’, and see the recommended run time.

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Step 3b: Hit ‘Next’. They list a table for Phoenix that suggests watering frequency and root depth. I used these to approximate a root depth. Since I had decent values in place for AWC, and with Rachio’s magic, I automatically got the intervals they suggest. Check!

Pasted image1172×711 132 KB

Step 4: I went into the Rachio settings for nozzles, and adjusted the PR down until I got to the suggested 8 hr times for shrubs, and 4.5 hours for trees.

Done.

Coudn’t Step 4 be easily spit out by a Rachio calculator once it has the information from step 3 so I didn’t have to make the empirical adjustment to PR? As you well noted, there are comments in the Water it Wisely site about moving the heads out to the canopy circumference and adding heads as the vegetation grows. In my case I haven’t had to add heads beyond the three per tree. Perhaps I got lucky because of the development stage of my vegetation. Our yards also tend to be reasonably dense in terms of the trees/shrubs, so I also think there’s some amount of H2O stealing from one plant to another for those that have longer roots. Don’t tell my neighbor, but I’m pretty sure my large Ficus is drinking up his water too. It’s not ideal, but if Rachio had this type of calculator built into their site I think it would get people a lot closer to a decent starting point, and would minimize the frustration highlighted by this thread. A single-point-emitter Rachio setup calculator like this could (and probably should) have a bunch of disclaimers on it that state the recommended uniformity and placement of emitters. That way people would know that this is an approximation, and the further they deviate from the assumptions the worse their estimate will be.

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40

Glad you posted that–I was just about to. You did a great job with the pics and your explanation!
One final step I took was to use a soil probe to confirm watering depth.

I’ve been thinking about this “gallon per hour” thread and like you, I found the flex daily for the lawn easier than the drip system. Besides, St. Augustine grass is tough and very forgiving, but the drip on the veggies took a lot of “tweaking” to set up so the tomatoes didn’t split and the cucumbers didn’t fry in the blazing afternoon sun.

Funny comment about the ficus. :smile:
My neighbor’s Indian Fig sent huge roots under the fence to my lawn. Now that thing is getting close to 10 ft. tall and the pads on it are over a foot wide.

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