My View

What you need to know about sustainable drainage

Keith McAuliffe of STRI shares his views on how to get more play through better drainage.

By Keith McAuliffe

Poorly drained golf courses lose revenue  

During my years of playing golf nothing was more frustrating than arriving at the course only to find the “closed due to waterlogging” sign up.  My personal experience is no doubt shared by many, and it is one of the reasons why I am so passionate about helping weather-proof sports surfaces.

Soil water is the key to quality turf
It is hard to single out any one of the many variables that constitute a quality turf system. However, if having to prioritise, I would place soil moisture (issues with too little or too much) at the top of the list.   For sustainable turf there must be enough soil water available during dry spells and sufficient water removal during wet spells. Most golf courses have an irrigation system installed and access to a water supply so, provided the system is designed and operated correctly, moisture deficit should not be a huge issue.

On the other hand a high proportion of golf courses have excess water (drainage) problems. Poor drainage, and the resulting problems of access and turf health, arguably represent the greatest challenge facing courses in high rainfall areas in the wet tropics of South East Asia and elsewhere.

Having firm, well-drained playing surfaces throughout the year is a pre-requisite for a quality golf course.  Unfortunately many golf courses are vulnerable to wet weather and the club suffers accordingly.

With a golf course just about anything can be done with enough money.  Arguably a number of our top courses that are built using a full sand profile are deemed to be effectively all-weather.  The reality is however, that not all clubs have the budget to build a course to the Roll Royce standard.

Given budget constraints and the extreme rainfall intensities encountered, it is to be expected, and possibly accepted, that if it buckets down for days it is unrealistic to expect no disruption to play.  A club will need to identify how much waterlogging and course closure can be tolerated. In my experience, if a premier club course is not playable within say 4 to 8 hours after cessation of a decent rainfall event then there is a drainage problem. For a lower budget course perhaps a 24 hour “return to play” would be a more realistic target.

What causes poor drainage?
Logically, high rainfall (or over-irrigation) provides the source of the excess water loading, but it is where the excess water goes to (or doesn’t go to) that determines drainage performance.

I encounter courses in low-lying flood plains or near the coast that suffer from a high natural ground water table, with resulting problems of surface water clearance.  Other courses, or parts of a course, are poorly-drained due to flood water runoff.   For example numerous courses throughout Thailand and Queensland were badly affected by storm water runoff and flooding in 2011, with reparation proving extremely challenging and costly. 

By far the most common cause of waterlogging in turf is where water is held up, or perches,  over a layer of low permeability material (such as a clay sub-soil or compacted base layer). The excess water on or in the soil cannot drain freely through the root zone, and may sit on the surface until it evaporates.

Soils wont drain quickly

Some soils just won't drain quickly enough

Poor drainage can be compounded by inadequate management practices.  For example, over-watering or uneven watering will add to the water loading.  Also, failure to control the build up of organic matter will encourage a softer, more easily waterlogged surface.

 

Key considerations in planning course drainage

It would be fair to say that many drainage installations fail to perform as hoped.  I believe this is largely due to poor understanding of drainage principles and drainage technology, and as a result use of inadequate methodology.  It is important clubs appreciate that:

 

  • sports turf drainage is a specialist business and clubs need specialist input with design 
  • every golf course is different and drainage design needs to be customised to account for specific site features
  • although good surface shaping and drainage sumps definitely help, the target should be to get excess water out of the soil once it soaks in
  • a pipe drainage system by itself is generally inadequate to achieve a high standard of drainage.  Secondary or supplementary drainage methods, such as appropriate soil physical treatment or close-spaced, narrow trench drainage, are required in order to shift water quickly to the pipe drains
Shallow pipe drain
Pipe drain that has been installed too shallow and the trench too wide
  • the performance of secondary drainage treatments will be enhanced by having a free-draining top layer, such as a sand topdressed layer.  Many golf courses in Asia sand topdress their fairways as well as tees and greens.
  • regular basic maintenance is important to ensure longevity of a drainage system.  For example, outlets from pipe drains will need to be kept cleaned and surface organic matter build up will need to be controlled.

There are several approaches that can be taken to drain a golf course, depending on variables such as budget and soil type. The most effective method is likely to be a combination of surface shaping with collection sumps, coupled with a close-spaced sub-surface drainage system.
 
One advantage in having worked with a range of sporting bodies over the years is that it has allowed me to observe what works in different situations.

When it comes to drainage I believe that golf could take a lesson from the sports field scene.

Sports field drainage performance has come a long way in three decades, with a combination of shallow sand capping and a close-spaced sub-surface drainage system being a proven recipe.  I know this system can also work well in golf courses, offering effectively all-weather playing conditions and at a fraction of the cost of a full sand profile system. 

In summary, poor drainage and resulting interference to course use (and maintenance) is an issue throughout the world.   Poor drainage is certainly a major issue in the wet tropics of SE Asia, where many courses have been built using local, poor quality materials.

To improve drainage performance is most likely going to require installing some form of sub-surface drainage system. Fortunately advances in drainage technology allow us to install systems that effectively firm up the surface, minimise surface disruption and which are relatively affordable. 

A final word of warning.  Ensure you get expert advice before planning any drainage improvement programme.  Although it isn’t rocket science, drainage design and installation need to abide by some key principles in order to achieve the best results.

The views expressed in this article are those of the author and not, necessarily, those of The R&A.