I think Patricks example with the popcorn river rock and what may or may not have went wrong with that project is a good example of how
easily a USGA spec method can get a bad reputation. In Patricks defense the specifications they followed were probably the specifications being
recommended by the USGA at that time. What year was it Patrick?
Of course clubs will follow the USGA's recommendation. But thats not to say that the model they specified at that time was probably
successful. The main objective with a modified green design is to utilize the gravel layer around the pipe and the bottom 6" of the profile,
while using a sand layer that will "bridge" over the gravel which means that it wont just slide into the gravel layer contaminating it and
clogging everything up.
In the beginning the USGA used a "choker layer" which was used to "bridge" the greens mix over the gravel layer. The choker layer
was sized to be slightly smaller than the particle size of the gravel and slightly larger than the greens mix, while at the same time allowing
adequate drainage into the gravel layer.
Where Patricks project may have went wrong was obviously choosing to use the cheaper gravel. I cant speak for what was available
around the Philly area back then, but I can say that when I was construction foreman for Empire Golf we had no problem getting
7/16" washed pea gravel for bunker and greens drainage. Its slightly angular but it wasnt uber-angular to where it resembled popcorn and
had nooks and crannies in it.
I am pretty confident a USGA agronomist didnt spec what Pats club used, the river rock was cheaper and readily available. If this was
the case, they should have postponed the project until they could afford the extra $5 - $10,000 extra to get the highest quality
materials. I dont know Pats club or if the greens were a success or not. But I do know that if they werent successful and it was attributed to
the USGA design (that went out of spec), it was a poor choice to save extra money in the beginning of the greens life. Especially when you
would have to come back and spend even more money than the money initially saved in the end to get it right.
I agree that it is a stretch for disease to be a problem being in the gravel layer. The pathogens for potential disease are always hanging
out in the thatch, organic matter and soil profile feeding and waiting for the perfect conditions to incubate. What Patrick's club could have had
problems with in the gravel layer is the overly-angular gravel selection catching precipitated bicarbonates and heavy metals such as iron in all
of the nooks and crannies of the gravel. That could very well be the issue and the result is probably the worst scenario imagineable with a
USGA green, having the pores in the deepest part of the green profile getting clogged up. If that happens, there is virtually no other choice but
to rip them up and start over. Because how do you rectify a problem that is even deeper than the 12" layer of greensmix? The only thing that
can think of is the use of acids to dissolve the minerals clogged up in the popcorn layer
In the past couple years there are companies that
have realeased acid products that do a good job instantly dissolving minerals clogging up the thatch layer and soil profile as a result of poor
water quality. Ive personally used Exximo and had good success with it. Its an acid developed initially to clean the inside of cement truck
mixers. My point is similar to what I said earlier about a green is only perking as fast as its upper 3". A green is also only perking as fast
as its bottom 3". The difference is its WAY much more harder to rectify the bottom of the soil profile, let alone the gravel.
In closing I can see why people lose faith in a USGA spec green if it is not followed by the exact specifications set by the USGA
using cheaper materials. Its not going to perform the way it should perform. And ultimately gets a reputation. I have no idea what the
situation is with the greens at Pat's club, its purely speculation based off of the fact that he said they went off spec with river rock that was
so angular it looked like popcorn. Im now sure if Pat hated me before he wants to f***ing kill me now! Dont take any of this the wrong way
Pat!! I could be wrong, if I am way off base go ahead and rip me a new a****le....
ps I have some messages I need to return to a handful of you and I will as soon as I get home this evening. Just wanted to keep up with
the thread.
I