USGA greens in the UK ?

[Scott Macpherson]

Adrian,

Do all your USGA greens have 3 layers? It was interesting what you were saying about the D Values, but how does that work if you only have the rootzone and the gravel (2 layers)?

In your opinion is the 3rd layer the key to perching the water?


Scott

[Brian Phillips]

Scott,

You achieve a perched water table as soon as you put a fine sized material on top of a coarser sized material nearly everytime. 

Where the USGA have come up trumps is that they have created a perched water table that drains when reaching a certain capacity therefore creating a profile that is very difficult to over water if built correctly but still retains a certain amount of moisture for the plant to take up.

The percolation rate is one of the most misunderstood parts of the USGA recommendation.  The American Golf Course Builders refuse to have it in their contracts (if I remember correctly) due to the inconsistencies that can occur when testing even at a USGA lab like ETL.

Probably the most important parts to the USGA green testing is the Porosity as this tells so much more about the actual amount of moisture that can be held in the profile or not.  It does not help if the rootzone drains at 1000 mm an hour if the porosity is so low that no moisture is retained in the profile for the plant to use.

The blinding layer is only important if you cannot get the rootzone and gravel to match.  This can risk to contamination of the gravel and the perched water table not working correctly.

The two best books to read are the following:

Practical Drainage for Golf, Sportsturf and Horticulture - MacIntyre and Jakobsen

and

Golf Greens, History, Design and Construction - Hurdzan

The first really goes into depth about the perched water table and the 2nd is as stated in the title.  Superb books for geeks like me.

[Ally Mcintosh]

That MacIntyre and Jacobsen book is absolutely the best for a full understanding of this.....

As Brian says, whether the third (intermediate) layer is required is purely down to the particle size and porosity relationship of the rootzone and gravel layer...

[Brian Phillips]

...and is the old fashioned way of building USGA greens as it is no longer a requirement since 2004.

[Brian Phillips]

For information to all, none of the Kingsbarns greens were built to USGA recommendations.  They used a minimum of 600 mm of links sand found on site to create their greens.

The sand was tested at different profile depths to find the cheapest and optimal depth for grass survival.  All sand was of course local on the site.

If I find sand on site I start doing a jig of joy as I would much rather use local sand than trying to build expensive USGA greens.  If you know what you are doing and with advice from an agronomist (with balls) then there is no reason to always build USGA greens.  Give me decent sand that drains and holds moisture and we are nearly there!!

[Ally Mcintosh]

...and is the old fashioned way of building USGA greens as it is no longer a requirement since 2004.

Is that right Brian?... I didn't actually realise that it had ever been mandatory...

I presumed that it was only when you couldn't source / afford rootzone and gravel that didn't meet the required bridging and porosity requirements...  I guess that IS the only reason since 2004...

Too much theory and not enough practice you see... Anyone who cares to change that, feel free to drop me a mail  

[Brian Phillips]

Ally,

Not strictly true what I stated so here is a pdf explaining what happened with the gravel changes.  It became easier to source gravel as the specs where widened....

[Ben Stephens]

Brian P

thats awesome!!! thanks for highlighting important references and the attachment re: USGA spec greens.  

600mm of sand for the substructure at Kingsbarns - how does the sand keep binding together to avoid collaspe?? - I have fallen (my leg in a hole on a sand based tee with that sort of depth.

Cheers

Ben

[Ally Mcintosh]

Thank you Brian...

I am glad you commented earlier (and Tom D before you) that even if money is no object, it is not always a necessity to build to the USGA recommendation... and sometimes, such as with heavily contoured greens, it can actually be a disadvantage...

Maybe I've spent too much time with Mr. Jones?

[Brian Phillips]

Brian P

thats awesome!!! thanks for highlighting important references and the attachment re: USGA spec greens.  

600mm of sand for the substructure at Kingsbarns - how does the sand keep binding together to avoid collaspe?? - I have fallen (my leg in a hole on a sand based tee with that sort of depth.

Cheers

Ben

Ben,

It is a minimum of 600 mm of a certain type of sand they found on site if I remember correctly.  The whole site was covered in sand in the end but it had to be excavated from the low part of the site. The 600 mm was used on top of other sand as well.

I really wish we could get an interview with Mark Parsinen and Stuart McColm (can never spell his damn name correctly) as they could explain the whole process far better than me.

[Brian_Ewen]

Any idea what they did at Castle Stuart ?

[Brian Phillips]

I think it was native as well.

USGA at The Castle.

[Adrian_Stiff]

Adrian,

Do all your USGA greens have 3 layers? It was interesting what you were saying about the D Values, but how does that work if you only have the rootzone and the gravel (2 layers)?

In your opinion is the 3rd layer the key to perching the water?


Scott

Scott - The first few courses I did, we did using a claybase, main drain + herringbones every 5 metres blinded the drains then put 12" of rootzone on, the remaining 7 or so courses I have done the 3 layers, although with The Stranahan (my latest) on some greens (maybe half) I ommitted the flint raft but doubed the depth on the grit layer. (I was buiding heaviy contoured greens)
With two layers the D-value relationships do become theoretically obsolete, athough you still need to consider the range of the two materials.
I really am not sure about the 3rd layer being the key, I think probably the relationship between the rootzone and the grit is more important but thats just my take on it thinking logically of how water is retained at the bottom of the rootzone - start of grit layer, afterall that is where your deep roots want to be and where the water reserve shoud be.
I have found that in the UK the USGA type greens I have been involved in have used similar amounts of water to traditional greens.
Maybe some UK greenkeepers could comment or if they are guesting email me adrianstiff@aol.com and I will post.

[Brian Phillips]

Adrian,

Why would you need to double the gravel layer just because you have heavily contoured greens?

[Adrian_Stiff]

Adrian,

Why would you need to double the gravel layer just because you have heavily contoured greens?

Brian - In a three layered system you only need 50mm as the middle layer between your gravel and rootzone layers. Drop that gravel layer and 50mm is not enough for it to sit on, so I go to 100mm depth which is probably consistent with the way a two layered system works.

[Brian Phillips]

Okay, now I understand.  So when you build a two layered green you use the same 100 mm as a USGA 2 layered green.

[Ally Mcintosh]

Adrian,

The way I understand it is as follows:

The gravel blanket should be 100mm, regardless of intermediate layer... IF an intermediate layer (between rootzone and gravel) is required, it should be a minimum of 50mm (to allow correct bridging effect)...

However, 50mm is a very thin layer of material to construct and thus it is actually easier (if slightly less cost effective) to create an intermediate layer that is thicker than 50mm...

Either way, the gravel blanket does not change its depth...

EDIT - Now I've read Brian's response, I think I may be answering the wrong question... Still, I'll let my comment stay and welcome any return comments...

[Adrian_Stiff]

Adrian,

The way I understand it is as follows:

The gravel blanket should be 100mm, regardless of intermediate layer... IF an intermediate layer (between rootzone and gravel) is required, it should be a minimum of 50mm (to allow correct bridging effect)...

However, 50mm is a very thin layer of material to construct and thus it is actually easier (if slightly less cost effective) to create an intermediate layer that is thicker than 50mm...

Either way, the gravel blanket does not change its depth...

EDIT - Now I've read Brian's response, I think I may be answering the wrong question... Still, I'll let my comment stay and welcome any return comments...

Ally & Brian - Yep thats pretty much it, in basic terms the 3 layered system only really involves 1 extra 50mm deep grit layer, this amounts to say 40 tonnes in a standard green so its not really crazy in terms of price. It is fiddly to install though; the older USGA methods said to effect the perched water tabe that each layer  should mirror its former layer pretty much exacty with a + or - tolerance of 10%... so whilst that is giving up a margin of say 10", 11" or 12" on your rootzone on your 50mm (2") grit layer you have a 5mm stretch either way...what we do after we have our gravel layer in situe is place buiding bricks which are 2" deep and grade the grit to our brick line...then move the bricks, we use an excavator to hold the material in the bucket but its handwork pretty much...saying that its probably 5 hours work for 2 men plus the excavator time. On 19 greens it might add say £30,000 to the end price. 100mm depth for the gravel is also a minimum, if the base is nice and hard, if it is not you may need to go to 150mm on your gravel..thats ££££ too. I still put my pipes and drains in at 5m centres, I am never sure if I am over speccing but its a tough thing to pioneer. You can as you say put a deeper consistent grit layer but I think the brick line method is quite easy to master and you save about £25,000 on materials.