Green Contour on USGA vs. Pushup

[Ben Sims]

I am partial to greens with quite a bit of contour or tilt.  Reading a list of my favorite green complexes is reading a who's who of great golf courses.  Crystal Downs, Oakmont, Pine Valley (16 especially); these are all wonderful greens.  More modern, I like the greens at Friars Head and the 10 I saw at Old Mac.  

But two courses stand out as my favorite greens.  Ballyneal and Wolf Point.  I find that the contour levels the playing field more than any course I've seen.  They also lend themselves to play from various angles as well as any course I've seen.  My understanding is that both of those courses were built on native material with slight tinkering on the greens mix, as pushup greens.  This is due in part to the soils they they started with at the site.

So this brings me to my question for the more experienced folk out there.  Say I want to build a golf course on a site with soil that retains water much more than sand.  A soil whose porosity is a high percentage of volume, but has very small pores and therefore holds water.  Clay-ish soil.  Logic would dictate that I would need drain tile, and piping to drain the green from the "bottom up".  Whilst also creating a perched water table for nutrients and water to sustain the rootzone.  This is the crux of the USGA green.

Can I build contour and slope in a green like those at Ballyneal and Wolf Point with precise levels of tile, pipe, sand and zone mix?  Is this viable?  Or is this the reason that so many great greens are built on sand?

[Jeff_Brauer]

Ben,

I think you can build almost any contour you want on a USGA green, but you have to get it right in the clay subgrade, and then be an equal 12" above that subgrade everywhere.  There is actually a little play in that, perhaps an inch or so, but you can't build a flat subgrade and then do the contouring with all sand, as the knobs will dry out.

Ask anyone in DFW, as I have built some wild contours with USGA or similar type greens.  And, I have added some of the micro contours using that inch play that you can get in USGA greens.  I have also flattened some USGA greens by filling the bottom of swales an inch or two and reducing knobs by the same amount.  Changing grade 4" over 50 feet or so can really bring putting surfaces down in slope, enough for today's faster green speeds.

[Kyle Harris]

Ben:

A few points to consider.

There are actually two "bathtub" construction methods, the USGA and California method. The main difference is the USGA green has a gravel layer and the California green does not. It's far more accurate to say that the USGA green has a "Hanging" water table and that the California green is the "Perched" water table.

The USGA green "hangs" the water table because the water is retained in the smaller pore space of the USGA-spec sand over the larger pore space of the pea gravel layer. At a critical point, gravity forces the water to overcome capillary action and flush out of the smaller pore space in the sand and into the pea gravel layer.

That being said, it is imperative with both forms of construction to match the compacted subgrade with the desired contours, as pointed out by Jeff. The difficulty with the USGA construction is that there are three layers to consider (Subgrade, gravel, surface) as compared to the California method with just two.

What you are calling native soil greens are probably greens where soil native to the site was available that matched the specifications in terms of particle size of the USGA or California constructions. The specs allow for the desired resistance to compaction, as well as the desired drainage performance and other characteristics. Any sort of modifications outside of the USGA parameters and the green will not perform as advertised.

Your question is best answered by looking up the exact USGA specs in terms of root zone mix, and amending the soil to match those parameters.

Remember, the chief motivation behind the development of the USGA construction method was not drainage, but resistance to compaction.

[Mark Luckhardt]

Pushup greens were/still are constructed using the bathtub method as well.
Most had a form of internal drainage, or it was added after failure of the drain sytem over time.

Kyle's last point about the USGA green being resistant to compaction is an important one. The sand green model allows a bulldozer to shape subgrade/final grade without destroying the soil structure of the rootzone. And/or complete the greens rebuild in a few days. A modern pushup style using pitchforks/mother nature to settle out a green will take over a month minimum as nearly all grading work is done by hand.

[Jeff_Brauer]

Speaking of old clay greens, one thing that surprised me when I first started as a gca is how rank those old greens smelled when you unearthed the subsoil, most likely from years of being too soggy and anaerobic.

I was also surprised that many of the old greens we dug up around Chicago had attempted some kind of gravel bed in addition to pipe, way before the USGA green method.  It must have been evident even back then that greens needed special treatment to grow as well as they needed to.

[Tim Nugent]

I read a research paper (maybe in GCM) that compared the amount of slope in all 3 green types and the effect the abrupt change in slopes that you get with decks/rolls/humps had on the uniformity of the the subsurface water over different periods of time.

As one might expect, even USGA greens couldn't produce a uniform water table as these areas tended to lose water faster and low areas retain it longer.

So, perhaps the answer is something Supt's have complained about for yrs - the less flat a green, the bigger the headache.

So, even USGA greens aren't as bulletproof as some would think and need an experienced manager.  And why you may see them hand-watering.

[Mike_Young]

Jeff and Kyle,
I have always been told and followed that the clay base of the green cavity did not need to match the top contour....my understanding is the top of the gravel layer needs to run parallel to the surface contour....yep or nope?

Tim,
Agree and heard somewhere that the USGA was not opposed to less mix in some of the steep slopes that were drying out...
Mark,
I have never seen a push up green built in a cavity or "bath tub"....what part of the country used these....

[Ben Sims]

Mike,

From the USGA website.

"The slope of the subgrade should conform to the general slope of the finished grade. The subgrade should be established approximately 16 inches (400 mm) below the proposed surface grade - 18 to 20 inches (450 to 500 mm) when an intermediate layer is necessary - and should be thoroughly compacted to prevent further settling. Water collecting depressions should be avoided. If the subsoil is unstable, such as with an expanding clay, sand, or muck soil, geotextile fabrics may be used as a barrier between the subsoil and the gravel blanket. "

My understanding is that general slopes should be followed with the subgrade.  The gravel layer is the first layer to be exact to contour.  Method recommended is staking.

[Mike_Young]

Mike,

From the USGA website.

"The slope of the subgrade should conform to the general slope of the finished grade. The subgrade should be established approximately 16 inches (400 mm) below the proposed surface grade - 18 to 20 inches (450 to 500 mm) when an intermediate layer is necessary - and should be thoroughly compacted to prevent further settling. Water collecting depressions should be avoided. If the subsoil is unstable, such as with an expanding clay, sand, or muck soil, geotextile fabrics may be used as a barrier between the subsoil and the gravel blanket. "

My understanding is that general slopes should be followed with the subgrade.  The gravel layer is the first layer to be exact to contour.  Method recommended is staking.

Ben,
I have read that before but I think somewhere they have agreed that the top of the gravel is the "big deal".....I have seen plenty of shapers/builders work the final contour by raking the gravel where it could vary by a few inches.....but I could easily be wrong....just please don't let one of those greens know it....it might freak and quit working....

[Kyle Harris]

Mike and Ben:

Perhaps the real issues is in saving in cost of material at the expense of cost in labor. Since the gravel blanket layer has a minimum of 4 inches, you'd use less gravel if the subgrade conformed to the surface contours, right? Each inch over the minimum is an inch more than is necessary.

[Philippe Binette]

Just a question,

when you're talking about a clay green, is it really just clay or it's closer to a topsoil / sand mix ?

where they building clay greens thinking that aeration and topdressing would do the job to make in work, or just because clay is a fairly good growing soil ?

[Ben Sims]

Ben,
I have read that before but I think somewhere they have agreed that the top of the gravel is the "big deal".....I have seen plenty of shapers/builders work the final contour by raking the gravel where it could vary by a few inches.....but I could easily be wrong....just please don't let one of those greens know it....it might freak and quit working....

Holy cow!  You mean the gravel layer wasn't exactly 16 inches!  Lord forgive them, they know not what they do!  :-)

My question is mostly one of logistics.  Can a layered green complex like a USGA green be contoured aggressively and still "do it's job"?  Is this why you don't see as many severe greens on clay/silty sites?   Could Mackenzie's 16 at Pasatiempo be a USGA green?    

[Mike_Young]

Mike and Ben:

Perhaps the real issues is in saving in cost of material at the expense of cost in labor. Since the gravel blanket layer has a minimum of 4 inches, you'd use less gravel if the subgrade conformed to the surface contours, right? Each inch over the minimum is an inch more than is necessary.

Kyle,
Agree...but otherwise the top of the gravel is the critical point....after that no changes....AND IMHO if all three surfaces need to run parallel...I don't think there is a green in the country where they can maintain 1" variance over the entire surface for 18 holes....and if that determines a USGA green...then they don't exist....JMO
Also, if one wishes to adjust slope or contour on a USGA green he can remove the rootzone to the gravel layer and adjust there....agree??

[Ben Sims]

Mike and Ben:

Perhaps the real issues is in saving in cost of material at the expense of cost in labor. Since the gravel blanket layer has a minimum of 4 inches, you'd use less gravel if the subgrade conformed to the surface contours, right? Each inch over the minimum is an inch more than is necessary.

Kyle,

Obviously I've never built one of these.  But it seems to me that contouring the subgrade would be the closest thing to "foolproof", especially in a reno job where the club wants to keep the former contours exactly.  But, even still, I'd be staking that thing every 2 feet to make sure!

[Joshua Pettit]

Speaking of old clay greens, one thing that surprised me when I first started as a gca is how rank those old greens smelled when you unearthed the subsoil, most likely from years of being too soggy and anaerobic.

Jeff,

The greens we dug up at The Valley Club had some of the nastiest clay I've ever seen.  A few of them (#16 in particular) even had large water pockets that had been stuck in the soil for years.      

[Mike_Young]

Ben,
I have read that before but I think somewhere they have agreed that the top of the gravel is the "big deal".....I have seen plenty of shapers/builders work the final contour by raking the gravel where it could vary by a few inches.....but I could easily be wrong....just please don't let one of those greens know it....it might freak and quit working....

Holy cow!  You mean the gravel layer wasn't exactly 16 inches!  Lord forgive them, they know not what they do!  :-)

My question is mostly one of logistics.  Can a layered green complex like a USGA green be contoured aggressively and still "do it's job"?  Is this why you don't see as many severe greens on clay/silty sites?   Could Mackenzie's 16 at Pasatiempo be a USGA green?    

Ben,
I think that is a good question and I it's hard to get that answer sometimes....supts will say they have slopes that are hydrophobic and you will hear a contractor say they can use less mix in these areas and not have the problem....the reason I don't think you can get a good answer is because if and I say IF there is a problem in these slopes....does the perched water table theory "hold water"?    Maybe just a good solid rootzone shaped to liking will work....

[Kyle Harris]

Mike:

I've heard stories of guys taking a cup cutter and digging out holes down to the gravel layer to gradually raise it so the root zone stayed at one foot after changing the contours of the green on the surface.

Ben:

I think the USGA construction gets a bad rap in terms of design limitations because of some of the concurrent ideas about the concept of a hole location needing to be a relatively flat area that's three feet in radius or whatever and the idea shown by an experiment that concluded a green sloped at more than 3% will not hold a ball rolled when the surface is faster than ten feet on the stimpmeter. It's not some much the construction method as much as the implementation.

[Mark Luckhardt]

Jeff and Kyle,
I have always been told and followed that the clay base of the green cavity did not need to match the top contour....my understanding is the top of the gravel layer needs to run parallel to the surface contour....yep or nope?

Tim,
Agree and heard somewhere that the USGA was not opposed to less mix in some of the steep slopes that were drying out...
Mark,
I have never seen a push up green built in a cavity or "bath tub"....what part of the country used these....

Mike,
Most of what I have read about early era golf green construction details a small cavity of +or- 4", of which a mixture of native topsoil,sheep/horse manure were mixed for the early growing medium. These savvy architects wanted to perch the gravitational groundwater close to the surface for droughty summer conditions,(because atomatic irrigation wasn't a buzzword yet) hence they built bathtub like greens to contain soil moisture for as long as possible.

All parts of the country/world used these type of greens or a modified version thereof, by the late 1800's anyways.

[SL_Solow]

Interesting.  When I spoke to the folks from XGD about improving drainage in our circa 1921 greens they described the construction process of that era as creating a bathtub to hold water because of the lack of irrigation systems.  Apparently this was the prevailing theory.  XGD apparently works to "drain" the bathtub when the soil is saturated.

[Mike_Young]

Pushup greens were/still are constructed using the bathtub method as well.
Most had a form of internal drainage, or it was added after failure of the drain sytem over time.

Kyle's last point about the USGA green being resistant to compaction is an important one. The sand green model allows a bulldozer to shape subgrade/final grade without destroying the soil structure of the rootzone. And/or complete the greens rebuild in a few days. A modern pushup style using pitchforks/mother nature to settle out a green will take over a month minimum as nearly all grading work is done by hand.

Mark,
Thanks for the info...
I had heard of adding the 4-8 inches as you describe but I had never heard of it as being in an enclosed depression....I was always under the impression it was open on the low side...  them ODG's are always surprising me...

[Tom_Doak]

Ben:

It is possible to build very undulating greens to USGA specs and nail the three layers and nail all the tie-ins -- but it is not NEARLY as easy to do as to build greens in native sand.

Our greens at Stonewall (North) and Stone Eagle and Rock Creek are all USGA greens, and there is a lot of contour in those three.  But it's hard to be as creative as we could be at Ballyneal or Old Macdonald, where you could literally decide to change/add/soften the contours the day before you planted the green, at no real cost.

[Jaeger Kovich]

The options for flexibility and changes with the sand/california sound like a great option if you can get the soil/grass combinations right. It took me an entire 8 hour day to stake out one of the greens for Kelly Moran's 3-hole expansion @ Heritage Creek. The green is so big and has so many tiers that I nearly ran out of stakes trying to capture as many of the subtleties for the USGA layering process!

If you were going to build a California green, would you go ahead and dig parallel standard gravel drains with perf pipe where you have cored out for sand? You'd get the benefit of the California, and not all of the cost of the p-gravel of the USGA

[Tim Nugent]

Jaeger, yes, but depending on the porosity of the sand, you may wish to tighten up your pipe spacing.  You are also best served to start your pipe layout by running a main up each swale and herring-boning off it. And make sure each main either has a 4" breather vent at the high end or has a lateral that ties into another main line that has one.  Otherwise you can end up with the same situation as when you put your thumb over the end of a straw and pull it out of a glass of water.

[Kyle Harris]

Jaeger, yes, but depending on the porosity of the sand, you may wish to tighten up your pipe spacing.  You are also best served to start your pipe layout by running a main up each swale and herring-boning off it. And make sure each main either has a 4" breather vent at the high end or has a lateral that ties into another main line that has one.  Otherwise you can end up with the same situation as when you put your thumb over the end of a straw and pull it out of a glass of water.

Isn't the purpose of having a specific porosity in the USGA spec sand to maintain the 15' off-center for the drain pipe?

Agree regarding the venting, you can never overvent a drain.

[Jaeger Kovich]

Those little 4 inch vent caps are expensive! Especially if get the fancy black metal ones:)