Application efficiency of MP Rotator?

Discussion in 'Professional Discussions' started by Bluelude1, Aug 9, 2019.

  1. Bluelude1

    Bluelude1 LawnSite Member
    Messages: 125

    Programming a smart controller for a system that uses all Hunter 40PSI regulated spray bodies and MP Rotator nozzles and can't find the efficiency data for such a setup.

    Drip is ~90% efficient
    Popups default as 70% efficient

    But the wholepoint of pressure regulated spray bodies & MP rotators is they are supposed to be more efficient ... Any idea what their efficiency actually is?
     
  2. rlitman

    rlitman LawnSite Silver Member
    Messages: 2,333

    Not sure where you got 90% for drip. Drip's efficiency for turf use depends a lot on the soil type.
    MP Rotators are sold as way more efficient than spray. I'm not sure how much more efficient they are over rotors.
     
  3. TX Easymoney

    TX Easymoney LawnSite Platinum Member
    Messages: 4,324

    that 90% number is typically taught as the rough benchmark for drip- I suppose if you install in sand, things would change for turf--though netafim et. all have a chart that addresses that issue-different soil type =different spacing/flow
    but they do market it all as 90% efficiency--I've seen point source stated at 100%-slope etc are to be accounted for in the layout and choice of drip/emitter spacing/flow rate-[​IMG] upload_2019-8-9_16-5-21.png
     
  4. HunterTekGeek

    HunterTekGeek LawnSite Senior Member
    Messages: 407

  5. ArTurf

    ArTurf LawnSite Fanatic
    Male, from Ark
    Messages: 6,377

    Blue,
    What is your definition of efficiency? What is the point of determining a number? Serious questions.
     
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  6. HunterTekGeek

    HunterTekGeek LawnSite Senior Member
    Messages: 407

    If you want a really deep dive on this, go to:
    https://www.irrigation.org/IA/FileU...s/2009/RevisitingTheSchedulingCoefficient.pdf

    I am guessing at Blue's needs, but it might be that he wants to calculate a Scheduling Coefficient (SC). Let's say that we need to put down an inch of water. NET...one inch of water. In a perfect world, let's say the sprinklers in that zone could theoretically put down one inch of water in an hour. So, set the run time to 60 minutes. That SC would be....1.0

    1.0 (SC) x 60 minutes = 60 minutes
    But with various inefficiencies you could have this:
    1.3 (SC) x 60 minutes = 78 minutes

    We know that nothing has a distribution uniformity of 100%. It could be 65%. Or 50% Or MP Rotators at 75% to 85%, depending on the spacing and pressure. So we have to add more run time in order to get a NET depth of one inch of water into the soil. Other factors like wind, soil infiltration rate, slope, etc., also play into the Scheduling Coefficient.

    Sprinkler efficiency affects how we adjust our run times to achieve the net depth of irrigation required for the plant material. Hope this helps.
     
    benhargreaves, hort101 and rlitman like this.
  7. CAPT Stream Rotar

    CAPT Stream Rotar LawnSite Fanatic
    Messages: 6,431

    Sprinkler nerds unite!
     
  8. TX Easymoney

    TX Easymoney LawnSite Platinum Member
    Messages: 4,324

    I like to use the spray and pray method myself
     
    benhargreaves likes this.
  9. HunterTekGeek

    HunterTekGeek LawnSite Senior Member
    Messages: 407

  10. rlitman

    rlitman LawnSite Silver Member
    Messages: 2,333

    Yeah, I've read that too. And maybe 90% makes sense for super-surface drip where so much of the water actually makes it to my shrubs that we can just wing it by pulling a 90% number our of our asses, safely assuming that runoff and evaporation don't have a significant affect, but for sub-surface turf drip I don't buy into such an oversimplified number.

    Exactly. And here's how that relates to my problem. The graphs in your link show a water depth applied over a two dimensional surface. That makes perfect sense when you're talking about spraying water from above. The non-uniformity shows up in two dimensions, with some patches being watered more than others.

    With sub-surface drip, water leaving the emitters not only spreads horizontally, but also vertically, in particular downwards. So now you need to picture the same map of non-uniformity in three dimensions. Or to simplify it, look at a cross section.

    That's shown in page 4 here:
    https://www.netafimusa.com/wp-content/uploads/2016/09/LSUBGD2-Subsurface-Dripline-Guide-Booklet.pdf

    So the problem still exists that we will have to apply extra water in some places, so that we apply enough everywhere.

    And I also want to know how much of that water ends up delivered beneath the root zone in my sandy soil. Because I suspect that would be quite a significant loss. Now to be fair, that's not an ecological disaster, because water delivered to the sand under the root zone here just filters down to recharge the aquifer it came from, and doesn't contribute to runoff or evaporate, so it isn't "lost" completely or causing other harm, but it does still show up on my bill.
     

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