Does this look good for MPR?

Discussion in 'Irrigation' started by CRUZMISL, Sep 11, 2005.

  1. CRUZMISL

    CRUZMISL LawnSite Member
    from zone 6
    Posts: 186

  2. Critical Care

    Critical Care LawnSite Bronze Member
    Posts: 1,654

    It almost looks as if you may be using PGPs in conjunction with MP rotators, but not all match up with the info I have. I'm wondering if you're figuring half precip rate for your single stream rotors (PGP?) that are set for 360 degrees? Charts are for 180 degrees.
     
  3. CRUZMISL

    CRUZMISL LawnSite Member
    from zone 6
    Posts: 186

    Yes Zone 5 has a PGP on the same zone as some MP's which will be swapped out next week for a 180 MProtator. Otherwise look OK?
     
  4. Critical Care

    Critical Care LawnSite Bronze Member
    Posts: 1,654

    Doesn't your zone 4 also use PGPs along with MP3000s? And zone 3, which appears to be all PGPs has a couple of #7 nozzles set for 360 degrees, but how did you come up with the .37 precip rate. I come up with about .21, as if that's going to make a big difference... Otherwise, from a glance, it looks fine - and fun.
     
  5. CRUZMISL

    CRUZMISL LawnSite Member
    from zone 6
    Posts: 186

    You are correct. I swapped those out a while back though :) The chart is a little old and I forgot to change those. Is the goal to match GPM and area or actual total precip. rate?
     
  6. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274

    The ideal would be to have all the zones matching in flow and precip. rate. But that being next to impossible on most irrigation systems the things to shoot for are:

    1. Matched precipitation rate within zones. Like heads with compatable nozzles set at proper spacing will help insure that you get MPR.

    2. Heads zoned for correct hydrozones. Try to keep heads in full shade areas off of zones in full sun areas. Keep the heads on the slope off of zones on the flat. These are a little harder to do and are usually dictated by price that the customer is willing to spend based on the competitive market.

    3. Proper watering schedule based on water requirements and watering window (amount of time available for watering).
     
  7. Critical Care

    Critical Care LawnSite Bronze Member
    Posts: 1,654

    Uh huh, this is for sure. When you think about it, what good will it do to match the precip rate for every head in a zone when perhaps half the heads in the zone are subject to different environmental factors. I wish I would have accounted for these factors when I installed my own system years ago, but back then I didn't know better. On paper my design looked great, added up great, but ended up with a couple zones that had areas in shade as well as sun. So guess what? After finding out that mistake, I had to go back and renozzle the heads so that I got less precip down in the shade, more in the sun. Could have been worse...

    Wind is another factor that can throw a monkey wrench into the works. It can be hard to plan around, can affect the at-ground precip rates, and can surely degrade how well a system works.

    But you know, you start with figures like you've done, do a little tweaking of those figures to account for other factors such as what Jerry mentioned, and then if worse comes to worse, just redesign the whole shootin match.

    Match GPM? No. As you know, larger size nozzles will typically have greater flow rates, and it surely won't always be possible to use exactly the same heads with the same nozzles, with the same radiuses on the same zone. Just keep an eye on the flow rate totals, which it looks like you have done already.
     

Share This Page