Peter Jones: How to improve the condition of your course’s bunkers
As winter approaches, most clubs will be commencing with their winter programme. Gone are the days when snow and hard frosts could be expected to bring work on the course to an abrupt standstill and confine the greenstaff to painting course furniture and the staff room walls, as nowadays the winters are much milder and the grass still needs to be mown even in the winter months.
With mowing to contend with, winter servicing of equipment and the restrictions created by short daylight hours and unpredictable weather, the winter period can be the busiest time of the year and an ambitious winter programme can stretch a greenkeeping team to its limits while trying at the same time to accommodate the all-year-round demands from golfers.
However, the opportunity to carry out construction projects and course renovation work can provide a welcome break from the routine summer maintenance work, and bunker renovation work can provide a great opportunity for teamwork and a chance to address some of the bunker problems that develop over time and can lead to a steady stream of niggling complaints.
Bunker drains tend to become clogged over time, and it is a worthwhile exercise on clay-based courses to dig an inspection hole in poorly-draining bunkers to check whether the perforated pipes or pea-shingle stone is becoming contaminated with fines. The chances are they will be.
A bunker with slow drainage performance which has got steadily worse over time due to the gravel becoming contaminated with clay particles? The remedy in this case was simply to replace the top 100mm of contaminated material, top up with clean pea-gravel, and cover the trench and sump with a well ‘crimped down’ strip of woven polypropylene geotextile to help prevent further contamination of the stone and the overlying sand.
Loss of shape, slope and correct gradients inside the bunker is another problem which tends to occur in older bunkers and more so in Colt or Braid style bunkers where the sand is flashed up a rising face. Typically, the levels in the bunker change over time due to wear and tear and erosion creating a cross-sectional profile which is significantly different from the original. This problem can create frustration for golfers who find their ball to be in the bunker on a downhill lie with the ball too close to an up-slope or overhanging lip.
Another characteristic of this problem is that the bunkers tend to retain water in the low spot and either have a lack of sand or a very damp sand which seems to be hard and compacted. Because these problems can develop over a long period of time, they can sometimes not be recognised as being problems which the greenkeepers could tackle themselves, and clubs can end up incurring large costs for having the bunkers completely rebuilt, which in certain cases is an unnecessary and expensive ‘overkill’.
The re-shaping of the bunker base also moves the low spot in the bunker to a more desirable position which is two-thirds of the way back from the front lip, which makes it the ideal place for the drainage collection sump.
Reshaping the bases of bunkers to achieve these desirable objectives is obviously not a ‘10-minute job’, and a lot of calculated thought and often needs to go into planning the resources required to carry out this type of work.
The use of a mini-digger with a tilt-bucket can significantly help to speed up the work and help to achieve the required firmness and compaction of the base, as well as install the necessary drainage requirements before the sand is put back in. Finding the right material to use for the base can also be a lot more difficult than it may first appear, as the material needs to have sufficient soil ‘strength’ to compact and hold its shape. If it is too wet, or indeed too dry, it may not be possible to compact the material properly, which is where experience and know-how will come into play.
If stone invasion is a significant problem, then it will be necessary to address that problem too. Unfortunately, most of the bunker liners on the market suffer from the problem of becoming exposed and ‘snagged’ on bunker faces within a year or two after installation, making them unsuitable in the medium to long term.
The use of a good quality, fibrous upside-down turf still offers a cost effective solution to dealing with stone invasion, provided that a sealed edge is created around the edge of the bunker. Once created, it is fundamentally important that the bunkers are not ‘edged back’ with the old style technique using a half-moon edging iron, as this could undermine or destroy the stone barrier.
To summarise, bunker renovation is a wide ranging topic and the extent of how far one can go with it will be largely dependent on the current state of the bunkers, and the problems incurred. The ability to carry out a rolling programme of bunker renovation work ‘in-house’ can be a rewarding experience and provide an opportunity to iron out problems before they become too major and expensive.
However, don’t underestimate the amount of time and resources that can be required to make a good job of bunker renovation, especially if tackling it for the first time. Be prepared to hire in some specialist machinery and know-how if it helps the job to run more smoothly and be a success.
Achieving the correct slopes and finding the right materials is key, as is using a replacement sand mixture which will compact to the required playability requirements and match the other bunkers from day one.
Bunkers remain probably the most contentious topic for complaint at most golf clubs and an appreciation of how to renovate them and also maintain them in good playing condition is a topic worth looking into in more detail and learning more about.