Mick Claxton from Shelton Sportsturf Drainage Ltd gives us his top tips...
Whether it's football, rugby, cricket or golf, the benefits of efficient drainage on any form of sportsturf are evident, but once the work has been carried out maintenance is often forgotten.
Over the years, a perfectly good drainage system can become ineffective if water cannot bridge the gap between the water logged surface and a perfectly functioning pipe system underneath.
Soil compaction is inevitable over time, but there are ways that it can be minimised and they can be very effective. It is advisable to implement a regular basic programme of slitting, verti-draining and hollow coring, which, when done in the right conditions, can help to aerate the soil and reduce the compaction that will compromise any drainage system.
However, even with an excellent maintenance regime, if the soil structure is of poor quality, for example with a high clay content, then drainage can still be sluggish. If this is the case, it may be necessary to renew or implement a secondary drainage system over the top of the primary system which will speed up the flow of excess water much faster than a primary system on its own. This can be done in one of three ways:
One of the simplest and speediest methods of installing secondary drainage can be done by Gravel Banding. This system uses a Gravel Band Drainer installing aggregate between 4-8mm in size at 1 or 2 metre spacing, installed at right angles to the primary system so that the bands connect with the aggregate that has been placed over the existing pipework. Gravel banding does not remove any soil but relies on it being moved sideways by the channel opener allowing the aggregate to be vibrated into the trench, it is therefore best done when soil moisture is high to minimise the risk of heave.
Another option is to use a Shelton System 25™ machine which is a versatile mini trencher used primarily for installing a secondary drainage system, over a network of piped drains, in a one pass operation. The System 25™ can also be used to install land drainage pipe and underground services. The trencher cuts a 25mm wide slit, removes the soil and lifts it into a trailer running alongside, whilst the aggregate is simultaneously vibrated into trench. The aggregate can be stopped short of the surface, allowing a free draining sand or root-zone to be placed over the drain run to leave the surface level and ready for play. This system generates fast results, the damage to the turf is minimal and it can be played on 24 hours later.
The third option is Lightning Drain™ which is similar to the System 25™, except the trenches are dug to 35mm wide and a 25mm perforated land drainage pipe is installed prior to backfilling with aggregate. This gives greater longevity and speed to the system as the water travels through the pipe rather than having to percolate through the full length of the trench. The results are immediate and, with good maintenance, including plenty of aeration, the effects will last for years to come.
As an alternative to quarried aggregate, you could consider using Lytag®, a man made material which has many benefits over gravel or crushed stone. Due to its round nature, the flow of water through the material is much greater than that of an angular material as the pore sizes are larger and more even. Its ability to retain water in the drier summer months also minimises the risk of the turf drying out above the drain line which can happen with gravel.
After the installation of any secondary drainage system, it is advisable to apply a sand top dressing over the drained area. This has the dual benefit of acting as a spacer in the top of each band/trench to keep open the connection with the surface and also allowing lateral movement of water in the surface to migrate to the drain runs. The benefits of sand top dressing cannot be underestimated and, if at all possible, a yearly application will pay dividends. In addition, to this it is also key to remember that good drainage creates the optimum conditions to encourage vigorous root growth which improves the soil structure and therefore, aids the drainage which is, of course, our aim. This can be optimised by timely application of a suitable fertilizer to improve root structure and therefore, soil stability.
Whatever the surface, green, pitch or fairway, regular maintenance is essential for optimum drainage performance, it really is worth investing the time now and you will reap the benefits for years to come!
Essential drainage maintenance tick list:
- Hollow coring
- Sand / rootzone top dressing
- Fertilizer application
Case Study: Smith Construction construct London 2012 Olympics Athletics warm-up area
Smith Construction applied a sand top dressing with excellent results on the London Olympics Athletics warm-up area back in 2012, after installing a secondary drainage system using the Shelton Gravel Band Draining technique.
They had originally installed a primary drainage system over the infield to the warm up track where the javelin, discus and shot putt was held, but the sheer volume of rain which fell during the months leading up the opening ceremony was so great, it was felt that a secondary system should also be implemented to ensure the ground stayed dry and firm and was in peak condition!
The wet conditions were ideal for Gravel Banding as the moist soil could easily be moved sideways by the machines mechanism to allow the Lytag to be vibrated into the band. The application of a sand top dressing over the entire area was the final part of the process and the results were immediate, a free draining surface fit for any medal winning athlete!