Handling of super saturated soil

As you probably know, we got quite a bit of rain last week here in Southern California. The golf course nearby has been closed until yesterday because of the wetness. Now it is open, but no electric carts are allowed–still quite wet ground.

So imagine my surprise when my garden began watering this morning! I cancelled it, of course, it is quite saturated still. But the moisture calculations seemed not to agree with reality. They showed it time to add water. I can only presume that the super-saturated condition is not being properly dealt with. I did a manual fill of the zones today, but they still think they will need watering on Sunday, two days from now. I seriously doubt the zone will be dried out by then, so I will monitor it and manually fill it again. (I had manually filled it a day or so after the last heavy rain, but forgot to monitor the situation since there was a light rain few days ago.

The moisture level seems to max out at 108%. I’m guessing it is about 150% or so right now. Maybe more. Is there a rationale for the apparent limit?

The current limit is 110%. We used to have a much more sophisticated algorithm based somewhat on this article (http://www.irrisoft.net/news/Quantifying_Effective_Rain_in_Landscape_Irrigation_Water_Management_IA_%20Technical_%20Conference_2009_%20Steven_Moore.pdf). The overwhelming feedback was that saturation limits were too high (sometimes up to 160%). We settled on something that seemed a little more realistic based on the fact that saturation is complex to measure. Did you receive 2 inches of rain in one hour, or 2 inches of rain in 24 hours? In our backlog we will revisit this and be able to use more granular hourly data to help dynamically adjust saturation levels, but this will take some time to build.


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The two inches was over 24 hours. But it had been raining basically all week and the garden was already saturated. For instance there are spots on our golf course that still have not dried out enough to allow electric carts. (But that should soon change, we have Santa Ana winds for this week which will dry everything out quickly.)

I looked at the article you cite. I think the situation in my case it that the excess water would count as “runoff” in the article. But unfortunately it does not run off as it is trapped by a wood grass barrier on the down slope side and the slope is almost negligible. I guess I need to keep watch and fill the zone until there is no more visible water. Maybe even a few days past that.

I’m also in Southern CA (Orange County) and have the same issue after, the significant for our area, rain. I hadn’t thought about adjusting the moisture level but I just did and that bought me a few additional days before the next planned watering. I guess I’ll just have to keep an eye on this for now.

Along the same lines, I’ve also had to water manually during Santa Ana wind events as the affect of the Santa Anas doesn’t seem to be completely accounted for by the Rachio model.


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Hi Franz - I’m a big fan but new user. I live in Northern CA where three years of drought were eliminated in about one month… everything is beyond saturated. I turned on my controller and just set up the daily flex schedule… it tried to water every station for about an hour each. At this point I have all stations turned off as I can’t seem to trust it to know that nothing needs any water. I’ve never watered anything that long in my entire life and in CA there are rules about excessive run-off. Is there any way to maybe set up intervals that I know work for my area and just have Rachio dial it up in the summer when it’s hot and dial it down in the winter / skip rain days? Thanks!

There are a few things you should do to start:

1 “Fill” your zones since they are most likely full and the Iro does not have the history to know so.
2. Be sure that the water output of your sprinkler heads predicted “reasonably.” Best way to do this is with catch cups, but given the current rain predictions that may not be feasible until summer. My experience is that the standard types do not match what actually is happening.
3. Be sure that the “root depth” for your zones is correct. I just fixed one of my zones (that I had not paid attention to) and it changed the next watering from Wednesday to a week from tomorrow.
4. You can always play with the zone factors until you get a watering time on the same order as what you were doing before the Iro. But remember that the Iro strategy is to promote root growth. That means deeper but less frequent waterings.
5. See also http://support.rachio.com/article/545-my-watering-times-are-too-high-too-low


What I like about the Daily Flex schedules is that you can “trust, but verify” the data that goes into the calculations.

sbillard’s advice is great. Use the web or smartphone app to drill into a zone and see what its moisture level currently is. With a new install, your zones are probably set to empty. Use the Details button to view the “behind the scenes” math.


Another thing you can do is set the freeze delay all the way up. It only goes to 45 degrees though. Here in so Cal that is basically zero evaporation or need for water. I use ifttt to trigger a one day rain delay at 50 degrees. It just hasn’t been warm enough to dry things out from the rains.


@sbillard, yes we would consider water over the saturation limit runoff. Sounds like the wood grass barrier is causing the water to pool. Is this installed for construction purposes?

@danckert, just curious, how long did you water before installing your Rachio? Are you attempting to water grass? Trees? etc?

Great tip!

@aristobrat, another great tip! Here’s a support article to learn more about moisture levels/graphs.

@Lars, what schedule type are you using? Flex daily schedules will have all weather intelligence features (including freeze delay) enabled.

The wood barrier is to make edging easier. But it would not really matter, without the barrier the water would still pool up and not runoff because there is no slope and a grass edge followed by a driveway. There is a similar situation for the back garden–that is a raised bed. But there the soil is sandy loam (because we had to fill the raised bed with something, might as well be good soil.) For the back garden, so far, the water does soak in. Still super saturated, but not so much a problem as the front.

I’m watering a variety of things… almost everything except grass. Established, native trees, fruit trees, schrubs, small plants, etc. I’m in northern CA - the last month has eliminated three years of drought in one month and it’s still raining so I’ve got plenty of time to figure it out. I can’t seem to find the saturation of each zone to “fill it” anywhere in the app. Thanks for all the tips!

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The ability to empty/fill is found on each individual zone’s moisture graph.

Hope this helps.



I can’t seem to locate the graph in the app…

Aww…it appears for any zones in a flex daily schedule :wink:


An update:

Yesterday we got 1.1 inches of rain according to the moisture graph so I am now at 110% moisture content. Forecast for today is .3 inches net of evaporation. So the 110% cap means that .3 inches of moisture is in the soil (no standing water) but not accounted for. Average evaporation for the week is about 0.04 inches so it will be a while before things catch up. Rain is forecast again for Friday, so no Manual Fill is needed yet.


sbillard, how exactly did you figure out root depth for each zone? My garden is mostly young trees and shrubs (mostly xeriscape plants, tore out the grass lawn). Just made a guesstimate?

You can actually dig down and find the extent, at least for grass. The size of the rootball of recently planted items would be a good start for an estimate.


During our epic California rains I had to use every trick to keep the rachio from watering. Flex daily schedules are not allowed in most so cal cities. You get certain days or day. The weather station delays helped a bit. Probably the biggest saver is the rain sensor I kept from my dumb controller. Even that would close after a few days so I added an ifttt to set a one day rain delay if the temp was 50 or less. The rachio wanted to water even though the plants were already drowning.

All this talk about filling in moisture graphs is silly. Less work to just adjust a dumb controller budget and be done.

So as we enter the warm season, I’m hoping the rachio will be smart enough to keep things alive. So far it is adjusting nicely to the warming trend.

@Lars, out of curiosity, do you recall what your crop coefficients were? Interested to know what settings you changed and what schedule types you were using. If I’m understanding correctly, you were not using Flex Daily schedules?

What type of controller were you using prior to installing your Rachio? I assume you were using the seasonal adjustment % as a global change to the durations of all active schedules?

Glad to hear! Please remember that the controller relies on the data reported to it and settings for each zone to make it’s decisions.

I didn’t adjust the coefficients. I simply programmed the crop, watering method etc. The only thing I changed in the advanced was the area. There is no way to determine what the coefficient should be other than trial and error. I guess you could just adjust the water time as well.

The previous controller simply had a budget to adjust all stations by a percentage to “fix” the season.

We had some rain the other day and the rain sensor activated for a day, though no watering was scheduled. Today the Rachio skipped the watering schedule due to “soil and temperature conditions.” So it looks like it is doing a better job accounting for rain and our ground is still damp. That’s great and it has been adjusting upwards in warmer weather as well to compensate.

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