Wednesday, November 21, 2012

Greens drainage (Falls Rd and Laytonsville)

Laytonsville and Falls Road have recently undertaken important major projects in order to improve the consistency of greens surfaces.  The vast majority of all greens in the MCG system are “pushup” style greens.  These are old (30 – 80 years old!) greens established on native soil, and “pushed up” over time by consistent topdressing programs.  While most of them perform well all year, there are a few in particular that don't drain well.  Over the past 2 weeks, Laytonsville completed work on the 14th green, and Falls Road installed drainage on the 9th and 18th greens.

In the picture above, you can see the distinct layer, about 5 inches below the surface (That 5 inches is the result of 30 - 50 years of sand topdressing!).  It was common in the “old days” to use a layer of inexpensive mason sand when the green was built.  This layer does NOT allow for good water infiltration into the soil, and even through years of deep-tine aeration and other practices designed to eliminate the layering problem, some greens continue to see performance issues due to the nature of the soil from 6 to 14 inches BELOW the surface.  If the green was shaped (during the original construction) out of a poorly structured soil that was terrible to begin with, then there is no amount of aeration or cultural practice that is going to alleviate the drainage problem to that depth.

This is why we have chosen to continue installing drainage in selected, wetter than average greens.   When some greens stay wet after rain, it means we can’t mow them with the others, providing inconsistency.  Furthermore, wet greens have more problems with turf thinning or loss due to anaerobic (no oxygen) conditions and increased disease pressure.  MCG’s goal is to continue to provide you with great conditions, and this can only be achieved by working on projects like this every year. (p.s. golf course superintendents LOVE these projects!)

Rebuilding a green completely to USGA specs can easily cost $50,000 per green.  However, modifying a green using our own in-house resources by installing drainage like we have just done here can be completed for less than 15% of that cost per green including labor costs.  Plus, a complete rebuild to a sand-based green would keep the hole closed for the good part of a calendar year while it is grown back in.  Our drainage work allows the green to be re-opened immediately following approximately 4-5 days of work!

We install 18” deep drain lines on 6 foot centers and backfill the trenches with a sand mix of 60% sand, 20% peat, and 20% soil.  This mixture is ideal for holding nutrients AND not draining too fast that they become unmanageable in the summer.  Why 6-foot spacing on drain lines??  Soil physics.  An 18” sand trench like this will pull water from about 3 feet on either side of it.   

Here’s how we did it:

Strip 7" wide lines using a manual sod harvester, cut sod pieces to length, and remove.  Look at all those nice aeration holes!
Keep sod pieces organized so they can be put back in exactly the same order they were removed.  This ensures that the sod lines are less noticable because the turf "pattern" on the green stays consistent.

Trench 18” deep (average) after laying down plywood along drainage channels.  Depth is varied to ensure water flows properly in the new drain pipe below given subtle undulations of the green surface.

Remove spoils.  Labor intensive, but sure does make a cold day feel a little warmer!  We try to make sure all traffic (foot and otherwise) stays on the plywood to reduce compaction and keep the surface smooth.

Install 2" perforated pipe, checking slope with surveying equipment.

Backfill and tamp the 6-2-2 mix often to ensure there is no settling.
       VERY carefully and precisely put sod back.  Each small piece could take 2-3 minutes or more to make sure it is PERFECT because you will be putting on it in about 2 hours from when this picture was taken!!

VERY LIGHTLY tamp the sod pieces into place once they are inserted into the channel.  Here we want to be careful not to compact the sod, but also make sure the surface is smooth.

6   Once completed, the greens are blown off, irrigated, and double, triple, or quadruple rolled as necessary to make sure they are playable.  Then, finally, we cut a new cup in the green and it is open for play the same day!  Our teams worked tirelessly to get these greens done and open for Friday afternoon and weekend play.  Kudos to a great staff!  We will continue to roll and will be doing some topdressing on these greens to help sod seams heal.

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