Irrigation Head spacing questions Cancel The title field is required!

1. Melvin Waldron

   

   43 posts
   
   3/10/2016 3:03 PM

   Reading in the text books, I am finding that I should space my heads at 50% - 60 % of the diameter. Now being the rocket scientist I am (I'm still waiting for that sarcasm font), radius would be 50% of the diameter, correct? (And said terminology has been misused by myself as I always thought it was 50 -60% of the radius). I will say when those correct nozzles are in place, they don't quite throw to the other heads in the triangular spacing set-up (71') we have. When doing an irrigation audit, we did find a few spots where coverage was lacking and it coincided with weak spots on the green (and not near the edges). Upon installing new nozzles that throw 30% further, we did see head to head (and a little bit more) coverage. Unfortunately we haven't redone the irrigation audit, since we had borrowed the audit kit for the first audit. But I can say through our moisture meter we are seeing good even results in moisture readings across the green.
   
   I guess my question is; is there a real detriment to having nozzles overthrow the designed spacing by 30% (because I'm thick headed and have already made the mistake once and somehow think I'm right, only because of what I am seeing)? Should I redo my irrigation audit to find the true answer?
   
   I do know irrigation head spacing isn't the only issue on this green as I do know it was constructed at a different time with another green, which both will dry down quicker, compared to the 12 others that were rebuilt at a different time.
   
   I ask these questions because we have upgraded from impact heads on a couple of greens to gear drive and we want to continue that trend, (and then we would use the old heads for tees and fairways repairs), and I want to purchase the right head and nozzle combinations. Also for some of the older heads that will not be replaced for a while we want to change out some of those nozzles.
   
   And on another issue of spacing, how do you all handle spacing issues when they aren't consistent (I've seen a triangle spacing on a green of 48 x 54 x 72 and the next one at 72 x 64 x 102)?
   
   Thanks!
   
   Mel

   
   Melvin H. Waldron III, CGCS, Horton Smith Golf Course, City of Springfield/Greene County MO
   
   
2. Andy Jorgensen

   

   1 posts
   
   3/11/2016 9:03 AM

   Typically, we do 80% of the radius to compensate for pressure drops during cycles. The reccomended measured throws are under full pressure, which most courses typically don't have due to aging pumps and poorly designed systems.
   
   On greens this is difficult to have spaced perfect, especially when part-circle heads are used. We did a renovation this past summer in which I personally spaced heads around greens. I had to eliminate the thinking of needing at least four heads on greens. So, some greens got three heads, some got four, some got five. But the spacing was more consistent than had we just put four heads on each green.

   
   
   
   
3. Corey Eastwood

   

   80 posts
   
   3/11/2016 12:03 PM

   I installed several new wail to wall systems. 62ft through heads at 58 feet. As close to perfect as I could get.

   
   Corey Eastwood CGCS, Stockton Golf & CC, Retired
   
   
4. Ronald Conard

   

   4 posts
   
   3/12/2016 12:03 PM

   Mel,
   
   I would start by going to the Center for Irrigation Technology site and see if they have your heads, pressure, and spacing tested for DU, etc. In a wind free environment head spacing should be short of head to head. If it is head to head the area around the head is too wet. In a high wind environment I've seen recommendations to go head to head. But wind is a factor you cannot really account for. It's never consistent and never from the same direction. The best you can do in that situation is go with a tighter head spacing and more heads.
   
   Anyway, to your question regarding spacings that are not equilateral, there isn't much you can do other than back them up with hand watering. Whenever I space out a green I do my best to do equilateral spacing. The designers' idea of just laying heads around the perimeter leaves us sups with a constant distributor battle.
   
   Finally, you can't just look at the throw and guesstimate if it is covering properly. You have to do catch tests and repeat them to find what works best for you. I use a program called "Space" for the CIT and it's possible to run single leg tests with shorter or longer spacings to come up with a distribution profile you can live with.
   
   https://www.fresnostate.edu/jcast/cit/software/
   
   https://www.fresnostate.edu/jcast/cit/goods/profiles.html

   
   
   
   
5. Melvin Waldron

   

   43 posts
   
   3/17/2016 10:03 AM

   Ronald Conard, CGCS said: Mel,
   
   I would start by going to the Center for Irrigation Technology site and see if they have your heads, pressure, and spacing tested for DU, etc. In a wind free environment head spacing should be short of head to head. If it is head to head the area around the head is too wet. In a high wind environment I've seen recommendations to go head to head. But wind is a factor you cannot really account for. It's never consistent and never from the same direction. The best you can do in that situation is go with a tighter head spacing and more heads.
   
   Anyway, to your question regarding spacings that are not equilateral, there isn't much you can do other than back them up with hand watering. Whenever I space out a green I do my best to do equilateral spacing. The designers' idea of just laying heads around the perimeter leaves us sups with a constant distributor battle.
   
   Finally, you can't just look at the throw and guesstimate if it is covering properly. You have to do catch tests and repeat them to find what works best for you. I use a program called "Space" for the CIT and it's possible to run single leg tests with shorter or longer spacings to come up with a distribution profile you can live with.
   
   https://www.fresnostate.edu/jcast/cit/software/
   
   https://www.fresnostate.edu/jcast/cit/goods/profiles.html

   
   
   Thanks Ron for those links.
   
   I know the real answer to my question is to redo the catch can audit. We will see on that green a puddle around out heads after running a cycle, but it doesn't hang around long. Just noticed from using the moisture meter how much better and consistent readings were after the nozzle change that threw head to head plus a little.
   
   Thanks!
   
   Mel

   
   Melvin H. Waldron III, CGCS, Horton Smith Golf Course, City of Springfield/Greene County MO