Bunkers: a modern challenge
Ian Tittershill says modern methods of draining bunkers can result in better results at lower cost.
Like many in the golf industry, I consider myself extremely fortunate. I travel the world meeting with industry professionals, visiting some of the most stunning and exciting projects and facilities and generally enjoying my work.
It remains true that golf architecture is subjective and what is ‘great’ to one person may not be so for another. The fundamental rules of golf course construction are, however, rather less subjective. The first lesson I learned in golf construction – which is just as true today – is that drainage is the key to a good course. This is never more important than in the design and construction of bunkers.
The lack of good drainage in bunkers on some of the most famous golf courses in the world remains a mystery to me. The use of bunkers as catch basins is not uncommon: the look in the superintendent’s eyes when I explain that the bunker and surrounding area was designed this way is something I never get used to!
Of course there are many issues to consider when designing or building bunkers: location, shape, size, slope, definition, relevance and last but most important, maintenance. But drainage remains paramount. Drainage is the fundamental key to a bunker working, the key to maintaining it and the key to performance.
I recently visited a prestigious golf course in Brazil, Fazenda da Grama. It is possibly one of the most beautiful courses I have been to and is cared for and maintained in a detailed and sympathetic manner. However, the greatest challenge the greenkeeper has is bunker maintenance. In the rainy season, the course will be hit with rain every day – between two and four inches each day for over two months. Every single rain event will washout and contaminate all 90 bunkers.
Simple drainage schemes have long been used in bunker construction. A drain consisting of perforated pipe with gravel overlaid has been considered adequate, or maybe just the only solution. The additional use of bunker liners has, in some cases, helped keep sand on slopes and eradicated an element of contamination between the bunker sand and indigenous soils. However, the fundamental drainage principles within bunkers need to be challenged if superintendents are to be provided with a product that can be efficiently maintained.
Water will move through sand under gravity. As rain (or irrigation water) saturates the sand, the water seeks to migrate from the slopes or faces downwards to the base of the bunker. This water movement causes washout or sand movement from the slopes. As the sand is moved, the water is eroding the faces and causing contamination. When the sand is returned to the faces by the greens staff, they will be placing a mix of sand and indigenous soils. This creates further problems of sand quality and will reduce the drainage capacity next time it rains. The water has now moved to the base of the bunker – so, ironically, the area which is the preferred place for playing bunker shots is the wettest part!
As noted earlier, standard drainage in a bunker usually consists of a pipe overlaid with drainage. The problem with this is that the moisture will only transfer from the sand (small voids) to the gravel (large voids) under gravity. A slow dripping process ensues and the bunker will eventually become drier. Clearly we need to look at the physics of water movement and develop a strategy to enhance the evacuation of water from the sand in a more efficient manner than simple gravity. The traditional drain effectively creates a perched water table in the base of the bunker, and while this is what we want on the green to develop root growth, in a bunker it causes a soggy mess.
Imagine having bunkers that are consistent throughout. No matter how much rain falls, the faces are the same as the base, and the sand remains on the faces. When discussing bunker construction with Stephen Byrne, course manager at the Wisley club in England, he indicated that consistency was his priority.
Bunker construction and lining is extremely important in both construction and maintenance. Bunkers account for less than two per cent of the playing area on a typical golf course yet account for over 25 per cent of maintenance costs. It would be fair to say that more money is spent on bunker maintenance than green maintenance on a modern golf course.
The challenge is to have bunkers designed, constructed and lined in a way that enables maintenance and works with natural conditions and environment. It is impossible to keep sand on 90 degree slopes and bunkers should be designed with maintenance in mind.
Our Sportcrete lining system is one product available which has been specifically developed to enhance the drainage of bunkers. Sportcrete is a system that works with the natural movement of water within sand and encourages the movement rather than fights it.
We all must be looking for bunkers that are maintainable and in the truest sense of the most over used word in the industry these days, sustainable. Now, there’s a thought: sustainable bunkers.
Ian Tittershill is managing director of Sportcrete.
This article was initially featured in the April 2010 issue of Golf Course Architecture.