Greens design/Irrigation design

[Don_Mahaffey]

On most of the golf courses I've worked at I've had to pay special attention to a few of the larger greens where irrigation spacing was irriegular due to the size of the greens. At my course here in TX I'm presently changing many of the heads around our greens due to very poor uniformity. Do those of you who design courses in arid areas try and take irrigation spacing into account when designing greens? I'm guessing you have to, but how much consideration do you give to irrigation spacing?

[Lou_Duran]

Don,

You may wish to talk to Urbina or Doak about this.  The Texas Tech project apparently required extensive irrigation work, well over 2,000 heads I believe, due to weather and climate factors (including wind), and the size of the property.  I am sure that they learned quite a bit from the irrigation consultant/contractor, and may be willing to share that with you.

Hope that everything is well at Palo Duro.

[Jeff_Brauer]

Don,

As a designer of about 20 Texas courses, I do.  

I recall being taken to task by members of this board for suggesting that the ultimate green size should be limited by the need to fit it inside the agreed upon sprinkler spacing.

While we don't do irrigation design, we agree in advance with our designer fairway (usually 80 triangular, but 70 or less in West Texas) and more importantly green spacing (almost always 70' triangular spacing, but 65 in West Texas)

This can mean limiting green size, or at least providing some inside curves at strategic - from the irrigation designers perspective  - points.  I have had a few greens modified by the irrigation designer in the field!  Some architects refuse, but I know from experience that if the sprinklers space out too far, or even get in a box pattern, coverage suffers and we all look bad.

[Mike Benham]

I know that Hunter use to manufacture version of the PGP that had a "sod cup" on top that allowed the head to be installed below the green turf.  They had some of these heads installed at Steele Canyon near San Diego where they had rather large green complexes.

[Jeff_Brauer]

Mike,

I have (inadvertantly) ended up with sprinklers on two greens.  The first was at Wild Wing in MB, SC where the owner wanted a 50K sq. ft. putting green, so it was unavoidable, but we used normal sprinklers, figuring if it disrupted a practice putt, no big deal.

The other was Stallion Mountain West, where my co-designer and original owner Jim Colbert was insistent on a large green with a "red cross" valley system in the middle, dividing it into four quadrants.  It got so large we needed the center sod cup, figuring disrupting a competitive putt was a big deal.

[A_Clay_Man]

Don- Forgive the amateur inquiry but it does seem that someone in your position would be able to customize the placement and size of heads for your particular needs. I know there's been much criticism of Ken Dye's irrrigation here and it is true that many of the high spots have trouble when just slightly starved. It seems to me that the only way to avoid soaking the entire green is to mix and match head sizes perhaps counting on the expected gravity to assist in transition areas. Does that make any sense?

[Jeff_Brauer]

Adam,

Irrigation designers really favor perfect triangular spacing.  Irregular spacing and different nozzles also tends to leave wet and dry spots.

Gravity should play no part, especially on sand greens.  Sometimes, if the designer starts with standard nozzles, the super can change those out, going with bigger nozzles with more output in higher areas, and smaller ones in lower areas to partially compensate for runoff.  He can also adjust run times, and I have seen supers do this for the two heads at the high side of greens versus the lower front heads, for example.....

[Don_Mahaffey]

Adam,
I've heard many times how a good super can overcome many obstacles such as poor greens construction or irrigation. I used to believe that, but I'm starting to believe that if it's done close to right from the beginning, then it becomes a lot more manageable. When it comes to greens irrigation in our area (assuming we have poor quality water with salinity issues) we're trying to accomplish two things. First, we'd like to be able to water the green evenly. Second, we'd like to be able to flush the sodium through the green's rootzone. Doing either of those things with out decent distribution uniformity of irrigation is a challenge that builds over time. Areas that get less water get dryer and the salts build there because there's not enough water to flush those areas completely. The salt concentration is higher due to the dryness and often these areas get very stressed. Hand watering or the addition of smaller heads doesn't solve the problem because these areas still get less water. If we turn up the watering time to get these areas wet enough, then the other areas get too wet. It's just not as simple as getting some water to the bad spots.

[A_Clay_Man]

Thanx Jeff and Don. So the problem is the evenness. Sounds impossible on too wildly undulating. What about that subsurface idea from reno?

[Steve Lang]

It would seem that the folks designing the irrigation piping network could provide some different pressure levels at different sprinkler locations to optimize the overall design, especially around greens.    

Just talking as a chem engineer..  its only plastic piping and some valves required for creating specific pressure drops..

[Jeff_Brauer]

Steve,

The heads only work in a limited pressure range of 70-90 PSI in most cases, with minor variations, and optimum in the middle range.  In essence, thats what the various nozzles do, with bigger nozzles throwing further, with more gallonage, and slightly different pressure.  Pressure affects the waters ability to fight wind, droplet size, eveness of coverage and a whole lot of other things, and should be varied too much.

As far as changing the pressure at each head on a green, pressure is a function of initial pressure at the pump station (usually 120-125PSI on golf course systems so the end pressure is close to the optimum 80PSI) length of piping from the pump station - so the extra 80 feet to the next head is miniscule compared to the two miles its flowed to get in the general vicinity - and elevation change, again, with miniscule differences around the green, even at a Stitwell Park MacKenzie green, compared to the total elevation change on a golf course.

Spacing for even coverage in all winds is the consistency design tool.  Individual head control (early systems grouped heads to run together) and run times are the tools for acheiving variety in application amounts when necessary due to shade, subsurface conditions, hilltops or valleys, etc.

[Larry_Rodgers]

Don,
Today's golf greens are built with a uniform sand base, some to USGA specs and some with a modification to the USGA. All incorporate information from soils 101. Whereas the base soil must acheive field capacity before water will drain. To answer your first question, today's system should be designed/staked to incorporae this principal. The sprinklers must be evenly spaced around the green to fill the "cavity" in a uniform pattern. Perfect 60', 65', 70', 75' or any other triangular spacing will NOT address the basic needs of today's greens. When we lay-out a greens system we GPS map the green and determine which spacing around the green will work best, the nozzle selection will be adjusted by the maintenance staff. Spacing is the uniform distance around the green to "fill the cavity".
  Unfortuneately Don you are stuck with someone's inexperiece with today's science of green construction. Uniform spacing is very important and so is an understanding of soils science. To correct the in efficiencies of your greens system will be difficult, first the actual greens mix profile will need to be identified, then an acurate as-built will need to be determined as to the spacing (X and Y). by the way just where in Texas are you as I may be able to come by in the fall (I do not do well in the heat) and map your greens for additional information.
  The project at Tech was most concerned with not being able to see the irrigation heads around the green, a concept I support fully. Toro manufactured a special sprinkler for the Texas Tech greens complex so the sprinklers would not be found or seen. The wonderful folks Tom Doak, Jim Urbina and Erik Iverson made great efforts to make the greens narrower to accomodate the "Y" spacing needs. When the course opens this year you should not be able to find any irrigation sprinklers around the green.