Advanced Zone Settings - Sprinkler Controllers

Last Update:Apr 23 2024 5:50pm • Est. Read Time:Est. Read Time: 7 MIN

Summary

This article explains how to edit Advanced Zone settings and explains each setting in detail. Advanced Zone Settings are primarily used for Rachio's Flex Daily and Flex Monthly schedules. The Advanced Zone Settings help Rachio calculate the schedule duration and frequency with the various attributes informing how much water your plants need, how much water is being put down and how that water is retained in the soil. If you want to learn how to optimize Flex schedules through these settings we han article for Flex Daily (link) and Flex Monthly (link). 


How can I edit my Advanced Zone Settings?

When you select a zone within the "Zones" tab, you'll see the Zone Details page. To edit your Advanced Zone Settings, select "Edit" and then scroll down to select "Advanced." Here, there are thousands of unique configurations possible based upon the characteristics of your lawn. After creating or updating a zone, default values will be assigned accordingly based upon the zone attributes. We recommend that only experienced Water Managers adjust these settings; however, the "RESET TO DEFAULT" button at the bottom of the page will reset the Advanced Zone Settings to those based upon the zone attributes of each zone.
 

Note

Remember to save your edits! To do so, tap on the "Done" button at the bottom of the Advanced Zones Settings page.

 


Full Breakdown of Standard and Advanced Zone Settings

Note

Changing these zone settings will not affect Fixed schedules when Seasonal Shift is disabled. If Seasonal Shift is enabled on a Fixed schedule, changing zone settings can affect the watering duration. For Flex schedules, changing zone settings can affect both watering duration and watering frequency.


Changing your zone settings has the potential to affect the watering duration of any Fixed schedules with Seasonal Shift enabled.


Zone Settings

Some zone settings directly translate to one or more advanced zone settings, and some do not:

  • Vegetation Type: Root Depth + Crop Coefficient
    • Affects both watering duration and watering frequency
  • Spray Head: Efficiency + Nozzle Inches Per Hour
    • Affects watering duration
  • Soil Type: Available Water [Capacity] (AWC)
    • Affects both watering duration and watering frequency
  • Exposure: No advanced settings correlation
    • More sun exposure increases the watering frequency
    • Less sun exposure reduces the watering frequency
  • Slope: No advanced settings correlation
    • Increasing the slope extends the soak time
    • Decreasing the slope reduces soak time

Advanced Zone Settings

  • Area: 
    • Only used to perform usage calculations; does not affect watering frequency or duration
  • Available Water:
    • Increasing this setting extends watering duration and reduces watering frequency
    • Decreasing this setting reduces watering duration and increases watering frequency
  • Root Depth: 
    • Increasing this setting extends watering duration and reduces watering frequency
    • Decreasing this setting reduces watering duration and increases watering frequency
  • Allowed Depletion: 
    • Increasing this setting extends watering duration and reduces watering frequency
    • Decreasing this setting reduces watering duration and increases watering frequency
  • Efficiency: 
    • Increasing this setting reduces the watering duration
    • Decreasing this setting increases the watering duration
  • Crop Coefficient: 
    • Increasing this setting increases the watering frequency
    • Decreasing this setting reduces the watering frequency
  • Nozzle Inches Per Hour: 
    • Increasing this setting reduces the watering duration
    • Decreasing this setting extends the watering duration

Advanced Zone Settings (detailed)

Area is the size of the chosen zone. Changing the area (square footage) of a zone simply improves the accuracy of the Rachio app's water usage calculator when the Usage Units in Account Settings is set to "Estimated Gallons" instead of "Time". Knowing the proper size of the zone, along with the precipitation rate (associated with the Spray Head type), allows the app to approximate how much water was used in a run.


Available Water  (AW) or  Available Water Capacity  (AWC) is the range of available water that can be stored in soil and be available for growing crops. The AW of soil is related to texture and structure, the spongier the soil the more water it can hold. Typical AW holding capacities represent the amount of water that can be held in an inch of soil; in short, how much water can be available for plants with the depth of the root zone is known.


Root Depth  (RZ) is the soil depth from which a plant extracts most of its water needs. The RZ is equal to effective rooting depth and is expressed in inches within the Rachio software. To determine the depth of the RZ, a soil sample containing the roots must be taken. It is recommended to use a soil probe to minimize disturbance of the soil and to obtain a good quality sample. Once the core is removed from the probe, look for the small roots to determine the number of inches from the top of the core to the deepest root near the bottom of the core. This sampling process should be done in several locations throughout the test area to determine an average depth.


Allowed Depletion  (AD) is the maximum amount of Plant Available Water (PAW) allowed to be removed (expressed as a percentage) from the soil before an irrigation refill occurs. PAW is the total amount of water held in the plant root zone based on Soil Type and Plant Root Depth. Increased surface evaporation (loss) of water and usually higher rates of transpiration are associated with frequent irrigation events; It is best to irrigate only when the root zone has reached the AD threshold.

  • For most landscape purposes, 50% AD represents a reasonable overall value for the typical soils and plants used in landscapes. 50% AD is the Water Manger's choice to irrigate when the soil moisture level is half depleted.
  • For sensitive, shallow-rooted plants (where little reserve water is available), or very heavy compacted soils, a smaller depletion should be considered (i.e. 30-50%)
  • For stress-tolerant plants, such as desert plants, deep root zones, or lighter soils, a larger depletion can be used (i.e. 50-70%)

AD represents a management decision to use the water that is most readily available to the plant. While plants can still extract water from the less available water reserves, the plant will begin to show signs of stress or wilt.

In short, AD is the quantity of water that is easily used by the plants from soil moisture without withdrawing all of the water prior to refilling the soil profile. Additionally, by allowing the soil to dry down, it draws air into the root zone. Roots use this air to breathe & grow; having the appropriate amount of water and air in the soil allows the microorganisms to flourish, enabling the plant (& soil) to be healthy.

 

Efficiency (DU),  also referred to as Application Efficiency or Distribution Uniformity (DU), tells us how efficiently the water is being distributed by the sprinklers. The lower the DU, the higher the run time needs to be to deliver enough water to the area with the weakest coverage.


  • DU is a factor used to adjust the run time to account for non-uniform distribution of irrigation water
  • DU is be measured by conducting a  catch cup or catch can audit

If the E/DU is below 0.40, then time and effort should be spent identifying what needs to be done to assure the system is operating optimally. This may include recommendations for improving maintenance or to seek the services of a certified Water Manager to identify the factors that are causing such poor performance. When the uniformity is low, it is hard to justify the amount of additional water needed to minimize stressed areas and achieve an acceptable appearance. When additional minutes of run time become excessive, runoff potential increases, and it becomes more difficult to do proper maintenance if the sprinkler system is operating beyond its desired or designated water window

  • Factors that contribute to water waste (and poor DU):
    • Pressure. In irrigation, there are two kinds of pressure, static and dynamic. Static pressure is the pressure of non-flowing water at the point of connection. Dynamic pressure is the pressure at a sprinkler head when the system is on. Static pressure determines pipe sizing and size of sprinkler zones, whereas dynamic pressure determines head performance. Both pressures are commonly misunderstood and can have a significant impact on the efficiency of a sprinkler system.
    • Different types of sprinklers are designed to operate at different dynamic pressures. Typically, spray head nozzles are designed to perform best at 30 psi, while rotor nozzles are designed to perform best at 45-65 psi. It is important to pay close attention to the nozzle pressure specification because certain dynamic pressures are required to obtain the desired coverage and radius of throw. Under pressurized nozzles typically produce dry rings around the heads, leading to overwatering in an effort to compensate for poor coverage. Over pressurized nozzles produce misting and small water droplets that are lost to wind and evaporation. Over pressurized nozzles also use 20-40% more water than properly pressurized nozzles, resulting in excessive, unnecessary water use.
    • Head spacing. Head spacing refers to the distance between heads, ultimately dictating nozzle size. Typically spray heads are used when spacing is in the 5 – 15-foot range; rotors are used for radii of 20 feet or more. All sprinkler types perform best when head to head coverage is achieved. Obviously, using 12’ nozzles on heads that are spaced 15’ apart is going to result in coverage issues. Again, it is critical to refer to the manufacturer’s specification to determine the correct nozzle size for the desired radius for the pressure available.
    • Nozzle selection. Nozzles for different sprinklers apply water at different rates. Spray nozzles typically apply water at 1.5” – 2.0” / hour; rotor nozzles are usually in the range of .5” - 1” / hour. The rate at which the nozzle applies the water is also a determining factor when scheduling the controller. A nozzle with a lower application rate, theoretically, will have to run longer in order to apply the desired amount of water.
    • Nozzle size can also significantly affect the hydraulics of a sprinkler system. Nozzles are not only rated for a radius of throw, but they are also rated for flow, referred to as gallons per minute (GPM) and or gallons per hour (GPH) for drip or micro-spray nozzles. A common mistake when visually evaluating rotor heads that are under pressurized, and not achieving head to head coverage, is to use a larger size nozzle that is rated for more distance. Under pressurization is more of a GPM issue than an actual pressure issue, i.e., too much water is flowing through the sprinklers than the supply can provide, by increasing the nozzle size the GPM is increased, exacerbating the problem. Decreasing the flow of a zone by using nozzles with lower GPM is the best way to resolve pressure issues if a booster pump is not an option.


Crop Coefficient (CC) Crop coefficients are properties of plants used in predicting evapotranspiration (ET). The coefficient is the ratio of ET observed for the crop. If ET is our zone checkbook debit, the crop coefficient will offset ET slightly and not remove as much from our account. Increasing crop coefficient increases watering frequency, and decreasing crop coefficient decreases watering frequency.


Nozzle Inches Per Hour is a measurement of how much water your sprinklers are applying to your zone. This rate is expressed in inches per hour, so is directly comparable to natural rain and evapotranspiration. Rachio has set up your zone with a default rate based on manufacturers' averages for the type of sprinkler head you selected for the zone.

Fixed Schedule Tips

If you're using Fixed Schedules, please note they are static and do not automatically update as Flex schedules do. As such, if you make adjustments to any of the Advanced Zones Settings, remember to recreate your watering times for the inputs to be properly calculated.

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