Monday, 24 October 2016

13th Green Drainage

As I sit here to write this blog I must admit to feeling slightly relieved that we have finished this project.

For all greenkeepers pitchmarks and scuffs on the green are a major headache, so you can imagine how it must feel to see the sacred turf lifted and soils below removed! 
This kind of project is not taken lightly but needs must. 

Last winter I got to see first hand, how wet the 13th green got. The moisture readings were around 57% in the winter, this is 27% higher than we want. (Moisture levels over 50% basically means the grass starts to die off as there is a lack of oxygen to sustain itself). 

Is drainage the right decision? 

After the readings we had last winter and the extra aeration and the days the green was kept out of play I knew we had no option but to drain the green. I needed more evidence to back up the theory. So we had soil analysis of the greens done. 

The results showed the top 4 inches are very sandy but below this a high amount of clay was present. This showed that infiltration rates would have been high but percolation rates would have slowed to practically nothing. In others words more water coming in from the top than realising out of the bottom. Like covering over a plug hole with a sponge and running a tap! 
This was all the evidence we needed and the plan was made. 


Now we knew for certain that the green required drainage, we planned the work to coincide with works around the green with the bunker project. This would work perfectly as the bunker and surrounds would require drainage too. This meant we could plug the green into that to save re doing it in the future. 

The job itself 

Okay I've given you all the information, I need to just talk about how we drained the green...! 

First we laser levelled the green to find which was the best place to put the drainage runs. 
(At this stage we were surprised the green moved a different way from the way it actually looks by eye, with a 50mm from right to left and front to back). 

We then marked the main and added the laterals in at 3m centres. The reason this is closer than fairway drainage is the speed we want the green to drain at. (Obviously we want the entire course to drain better but all drainage costs money but our priority has to be draining the greens the quickest so play can continue). 
The general rule is greens,tees and aprons 3m spacings, fairways 5m, roughs and semi rough 10m. 

Next the turf was cut and lifted. As we lifted each section it was numbered and placed on a tarpaulin (to stop it rooting, while off the green). The end of each line was numbered + letter (M= Main L= lateral) so the turf would go back exactly where it came. This over time would mean the world would be seemless.

During this process we found the middle of the green was showing signs of anaerobic conditions (suffocation, even before the winter had set in). This can be seen in the picture below. The soil is turning black. You can see where our aeration work has been done because this is sand coloured.

At this point I knew we were doing the right thing. This green wouldn't have survived the winter. 

Once the turf was stripped we were ready start the drainage. 

The green was trenched out and the spoil was used towards shaping the sub base of the new bunker on 13th. So keeping the runs short and the trencher going. 

This is the trencher we borrowed from Muswell Hill GC (thanks to the them). 

Lots of digging out at the ends to get the levels right was required and the greenstaff done a great job on it. 
You can also see the width of the turf cut and the trenched line leaves very little in the way of room! Both Graham and I had "fun" with this but we managed it.

Our main was trenched to 650mm and our laterals were 600-550mm deep. The bases were lasered and the levels corrected before and stone or pipe was added. 

Drainage needs to be deep for two reasons. One so aeration avoids it in the coming years or there will no point putting it in as this will be a pipe with hundreds of holes in it and secondly to encourage a 'pull' so the water heads to the pipes, this creates a vacuum in the soil and pipe work, making the drainage work efficiently. 

At this point we could see the underlying problem in the middle of the green. A clay layer just 120mm down. This grey clay is our problem. Our infiltration rate would be high as you can see the sandy/soil layer above but once it his the grey clay it would go nowhere. 

This green would have be built like this on purpose... 

The reason would have been irrigation! 
I know it's mad when I am talking about drainage but old greens (before the 1970's) were built with a clay base to hold water as irrigation systems didn't exist in the summer so they wanted them to hold water. Irrigation system started as a hose pipe but later computer controlled were not really popular until the early 70's. 
Golf has changed and greens that were built to hold water and now required to drain and play well in the winter, hence why these works and maintenance weeks works are essential! 

Once the levels were right a stone base (1/2 inch) was added for the pipe to sit on. I like to do this to keep the pipe as clear from silts as possible. 

Next the pipe work was added. The laterals were 60mm (self flushing)
And the mains 80mm. 

The mains was then linked up with the bunker project and runs to a ditch. This means at each stage the outlets get bigger from the start!

At this point it's worth noting on the greens all work too place in boards. These needed to moved and the area cleaned constantly so damage to the greens surface was kept to an absolute minimum. Again the team done a great job at this stage too.

Once the pipe was in and the joins made we then added the stone layer. We used our new conveyer system on our topdresser. This saved a lot of manual handling and increased our speed. 

After the stone the rootzone was added in layers and then compacted in. This is very labour intensive but helps to minimise sinkage in the future. 
The rootzone was made from the same sand as the club has top dressed with for years so it was compatible. 

Once our levels were high enough we used a modified wacker plate to compact the top layers. This saved time and done a great job. Thanks to Parkstone GC for lending us that too. 

During the whole project we had to keep the rest of the green in good state for re opening. This was mown by Levi using a hand mower three times a week. It definitely tested his skills!! 

During the final 3 inches of topping up we added mycorrhizal fertiliser to the soil to encourage rooting ASAP once turfed. The final level was then finished using a normal wacker plate. 

The green was then turfed using the turfs in the same places like a numbered jigsaw.  Great care and attention were needed at this process too as our mowers cut at 3 to 4mm so the levels have to be spot on. 

The green was then fully turfed and just needed time to recover. 

The aftercare

Four days after turfing the green was rolled for the first time to smooth it out. I was already impressed with the rooting at this stage. This is something we have carried on with.

The drain lines were topdressed before opening and again this is something we will work on to get the final levels right. 

The following Friday after we turfed the green was looking a lot better. Little and often liquid feeds will be on going now. 

7 days after we laid our last turf the green opened back up for play. The speed of the recovery and rooting was brilliant. 

My final thoughts 

For me the green basically got heart surgery and this should make a huge difference as we go forward. 
The greenstaff done a fantastic job from start to finish and I couldn't have asked for more. Thank you guys! (Thanks also to Richard and Jayne and the pro shop for keeping the membership and visitors informed of our work).

All the work was completed in 22 days start to finish (not bad considering it was out of play for over 30 days last year due to water logging). 

We still will be working very hard on this green in the coming months but it will now drain and the future for that green is very bright or dry :-) ! 


While I am talking about drainage, it was nice to see Graham got some pictures in our recent down pour from the 17th, you can see the drains doing there job! 

I hope this has helped to show you the works that have been going on. Sorry it's a bit later than normal. Finding time to write all this down is hard! 

Next blog... The bunkers stage 2


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