Hunter’s Root Zone Watering System

Discussion in 'Irrigation' started by Critical Care, Mar 21, 2007.

  1. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    Okay, now that Hunter has officially introduced its RZWS (Root Zone Watering System) I’m anxious to see how many people will flock to these.

    Basically being an underground bubbler, or drip system, I’m still presuming that the effectiveness of the RZWS will largely be dependant upon the type of soil. Any bubbler, above ground or below, will very likely have a tougher time saturating soil in a horizontal plane than vertical, especially if the soil is something like marine sand. Let’s face it; a lot of people are turned away from drip irrigation because of poor horizontal dispersion.

    I do see benefits to the RZWS in some cases. Hunter mentions that the system encourages roots to grow deep and to remain below the surface… Sure, but my question is as the roots of a tree grow beyond the influence of the RZWS, then what happens? Can you keep a mature aspen from sending up suckers thirty feet away?

    Hunter mentions less runoff when using RZWS. That certainly makes sense if you’re comparing it to a similar above ground system. The RZWS can be equipped with drip emitters, but as the flow rate decreases to GPH rather than GPM runoff certainly will be less of an issue, below or above ground. Right?

    So… given the right place, the right situation, would you go this route?
  2. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    I've always thought of these as "root attracting systems", and it seems to me that if you really want to have a horrible root ball covered repair in 10 years, then by all means install them.
  3. Mad Estonian

    Mad Estonian LawnSite Senior Member
    Messages: 280

    I was actually at a Hunter demo today, and the RZWS was unveiled to us (not in person, just on the screen). I asked about root infiltration, obviously they're aware of that, but their thinking seems to be that these would really only be needed for the first couple years, then the tree would be established, with deep roots, thanks to the depth of the watering, and you could just disconnect the zone(s). At least, that was my take, I hope I'm not distorting the guy's info. Apparently, the RZWS is just a means of making an official product out of what some guys have been doing themselves for years, with larger-diameter PVC pipe as a sleeve for a bubbler. So, I'm sure it will make some people happy. I'm actually a big fan of drip emitters, of course most of our soil here is clay loam, so the distribution is good. As a side note, I asked why Hunter doesn't make drip emitters, and was told that apparently a few years back, Ed Hunter held an Israeli-made emitter in his hand, and could tell by the weight that just the material cost for them would be higher than that emitter's retail price. So, he understandably decided not to go that route, though the rep said that it's inevitable that one day they will have something in that market. I also asked about the MP Rotator, he said that they are doing some testing on something similar, but there's nothing close to a finished product yet. Overall, a pretty informative day, and I really want to get an ET station installed at one of my customer's places, where there's 20 zones of micro (it's a botanical garden, over 200 rhodos, etc.) and the water bills are a bit on the high side.
  4. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    I haven't seen it but it sounds similar to the Rainbird one. I asked about that one a few months back and I don't think anyone here was using it.
  5. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    We have a tree system that we put in along a river bank about 15 years ago using perforated pipe and it still seems to be working.

    Israel made a desert bloom and seems to be the leader when it comes to micro irrigation. It's a necessity instead of luxury. :)
  6. irrig8r

    irrig8r LawnSite Platinum Member
    Messages: 4,553

    Isn't this just a copy of what Rainbird has had for a few years? I noticed RB has several sizes now. Do you folks that use these regularly fill them with gravel or drain rock? If not won't they fill with roots? I've only used them on 4 jobs, and that was a few years back with some 24" box trees in planters surrounded by pavement, where runoff could be a problem and we needed to encourage deep roots.
  7. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    I haven't seen them used here on any of our new sites that tend to have a lot of concreted areas and tree wells. The standard bubblers are being used by the LAs and Irrigation Consultants that do the designs for these new constructions. Trees in these situations are a PITA. One middle school that is approximately 10 years old has tree wells in a courtyard and the irrigation has already basically been abandoned because the roots have choked off the PVC pipe and we've experienced leaking under the concrete. But the trees looked pretty when they first went in. :)
  8. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    You would think that if tree roots can actually choke off PVC pipe, they could also easily get into a root zone watering system. Since trees manage to take root in solid rock, such as Sierra granite, I wouldn't think that drain rock or gravel would be too effective in blocking roots from entering the RZWS, just as drain rock doesn't stop roots from entering into a septic leach system.

    But what about root deflectors? I see some municipalities using them in an attempt to encourage roots to grow deep, instead of breaking up sidewalks. Like the RZWS, I'm a bit apprehensive about the effectiveness of root deflectors as well.

    Hmm, maybe some ingenious person could mount several low flow bubblers around the inside of a root deflector...
  9. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    Then you'd just have a larger root zone watering apparatus. :laugh:

    I've seen good and bad from root barriers. I actually think it might have more to do with the type of tree/roots than the barrier though. One high school had above ground planters in front of its gym with root barriers for the trees. The Bradford pears seemed to work well with the barriers while some coastal redwoods broke the planter walls by sending roots through/over/under the barriers. They took all the planters out this past year as they were a safety hazard for skateboarders and didn't want a lawsuit.

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