For professional superintendents, golf course maintenance is a practice designed to create the optimal playing conditions to enhance the golfers overall playing experience.  Removing contamination and stones from golf sand bunkers makes them consistent in their structure and allows players to fine tune their game. The goal of uniformity is time consuming, made more difficult because there were no powered hand tool to assist the effort and because manual screened hand tools are ineffective when the sand is wet from weather or watering. 

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How to Cost-Effectively Rebuild or Renovate Sand Bunkers

• December 1, 2010 12:00 am
• Rob Thomas
• Course & Grounds, Featured
• Club and Resort Business

 

SUMMING IT UP • Bunker liners have increased in popularity because of their ability to hold sand in place, while allowing sufficient drainage. On the flip side, this method can become costly. • Choosing the type of sand to use can make or break a bunker project. For every consideration from color to the size and shape of granules, consulting with area superintendents can go a long way towards finding the best sand for filling bunkers. • Deep vs. shallow or large vs. small, bunkers come in all shapes and sizes. But in every case, two questions must be answered: Is the maintenance staff equipped to keep the bunkers in prime condition? And will their difficulty negatively affect speed of play?

Life is a beach, but mixing a day on the golf course with one in the sand can test anyone’s game and patience. While golfers rarely enjoy playing out of a hazard, bunkers are an integral part of a course’s design. They define the landing areas, make for a visually exciting layout, and in many cases are what supply the strategic challenge of the game.

Sooner or later, though, every golf course superintendent faces another serious challenge: How to cost-effectively rebuild or renovate sand bunkers. When this time comes, there are a number of important factors to consider—and no single “right” or “wrong” answers.

For insight into all of the variables that must be considered and weighed in a major bunker project, let’s take a closer look of how two courses, at opposite corners of the country, each worked through their choices when faced with the need to deal with long-developing bunker distress.

Determine the Need
The 18-hole “Riviera” course at the Riviera Country Club in Coral Gables, Fla. (just outside of Miami) measures 6,511 yards from the longest tees for a par of 71. Designed by Donald Ross, the Riviera course opened in 1946.

Since then, it has undergone a series of renovations and improvements. In 1993 a driving range, short-game practice area and pond were added, and 10 years later some greens and bunkers were restored.

Through it all, however, a bunker renovation storm cloud was brewing.

Coral rock—not sand,  as in other areas of Florida—is the main soil makeup  underneath Riviera’s course. Additionally, Coral Gables receives more than 65 inches of rain each year.

Those two challenges, plus regular wear and tear, had wreaked havoc on the course’s traps.

“That coral rock worked its way to the surface and contaminated the sand,” explains Director of Agronomy Eric von Hofen, who reached out to a New Hampshire-based golf course architect to help him renovate the sand traps. “The architect was brought in during the fall of 2009 to review the bunkers and work with me to come up with a design. We ran a GPS on each bunker and produced a working plan, to show the committees and Board what new bunkers would look like. I then placed the project out to bid.”

Similarly, the bunkers at West Seattle (Wash.) Golf Course—a 1935 Henry Chandler Egan design that is maintained by the city of Seattle—were also showing their age. So the city approved a capital project to renovate five existing bunkers and construct 18 new ones.

Fifteen of these “new” bunkers, though, would actually be created by unearthing hazards that had been filled in many years earlier, to reduce daily maintenance demands. Actually, more than 15 bunkers had been filled in over the course’s history; so in choosing which ones to recreate, West Seattle’s Superintendent, John Price, selected those that he felt would not impact less-experienced players, while still visually framing, defining and enhancing the beauty of each hole.

The remaining eight bunkers would be new locations, four as fairway bunkers in the landing areas for longer hitters (250 to 280 yards from the tee). “We wanted to get the most visually out of each and every bunker,” says Colin Gants, the club’s PGA Head Professional.

Liners in the Sand
There are many ways to build bunkers—but the one thing they all must have to function properly is drainage.

Generally, bunker sand gets contaminated with silt. In time, the silt then tends to plug up the pores in the sand, causing an inability to drain quickly. When bunkers don’t drain, pools of water allow the sediment from outside the bunker, or even beneath it, to contaminate the sand.

To minimize this, erosion-control products—such as bunker liners—are very effective at preventing washouts, especially on steep-faced traps.

Although liner suppliers will often recommend covering the whole bunker, many superintendents have found that installing this material in only the steep areas will prevent the washout on the face. This fabric is not cheap, but it does not take long to recoup the costs of the material through the labor costs that are saved when not having to repair washouts after a rain event.

To address their drainage needs, Riviera and West Seattle took two different approaches—both of which are finding success. Following extensive research and consultation, Riviera chose to go with a thin liner, which saved money—but the coral rock forced some imaginative installation.

West Seattle, though, went with no liner at all, instead choosing to go with sod and fill with sand.

“It’s a safety issue,” Price says. “I almost broke my wrist [swinging a club into] a bunker liner, so it didn’t take long to convince me.”

Finding the Right Grain
To some degree, the sand selected for a bunker renovation project is a function of budget, as well as the nature of the course itself.

When deciding which sand was best for Riviera, von Hofen built test bunkers with four types of sand and offered his members an opportunity to provide feedback.

“We are very lucky with our location in Florida and the different types of sand we have at our fingertips,” he notes. “I wanted to test one that was fine, one that was angular, and one that was a mix of the two, as well as the existing sand.”

Each one of these sands drained differently, had a different shade of white,  and a different pentrometer reading, which measures the resistance to producing a buried, “fried egg” lie. The higher the number on the pentrometer, the less chance a golf ball will plug into the sand and become unplayable.

Next, von Hofen looked at the shipping costs for the various varieties from three different areas of Florida. Each sand came from a different mine and was processed differently. The angular was the most expensive, because of how it was processed. “Price-per-ton was shocking,” says von Hofen. “We eventually selected a sand in the mid-range, and the members are thrilled.”

Riviera also saved $30,000 by stockpiling the original sand removed from the bunkers, ultimately using it to topdress the fairways.

West Seattle’s Price, who says his course pushes through approximately 65,000 rounds each year, chose a grainy sand—a mixture of three different-sized particles. “The players love the sand and addition of the bunkers,” he says. “We have selected beautiful white sand that is an industry premium in terms of playability, consistency and quality.”

If You Build It…
According to von Hofen, the $325,000 bunker project was the best and most effective way to change the look and playability of Riviera. “The views from every tee box have changed so much that each time you are teeing off, you stop and your eye is drawn to the sand and shapes in front of you,” he says.

Riviera remained open for play during the 52-day project, with play only restricted on the hole that was being worked on at that time. “That was a small price to pay for such a great finished product that members and guests love,” von Hofen notes.

West Seattle took eight months to complete its bunker renovation, but the feedback has been extremely positive.

“These are tough times,” Price notes. “We have to deliver a great product to each customer. There are no ‘gimmes’ in this industry any more.”

 

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Building effective bunkers is a challenge

This article first appeared by Andy Cole in Golf on March 5th 2010

A bunker, generally sand filled, is positioned within the layout of a golf course to be a hazard to play - often referred to as a trap or "just a damned nuisance".

An architect would take the view that bunkers, strategically placed, encourage the golfer to think about the shot to be played. Fairway bunkers are often referred to as "positive features", designed to make the golfer think about where to place his shot. To lay-up short and have a longer second shot to the green or to accept the challenge, clear the hazard and be in a better position for an easier second shot.

The changes in golf club and golf ball technology have sometimes necessitated the movement of bunkers to bring them back into play. I find it fascinating that higher handicap golfers sometimes object to bunkers being moved on the basis that they have become popular bunkers - but unfortunately penalizing the less able golfer, who, it is often said, "carries his own bunkers around anyway".

It is essential that the golf course is set up to challenge golfers of all categories.

Greenside bunkers, on the other hand, are generally regarded as "negative features", not necessarily positioned to make the golfer think about where to hit the ball, but certainly there to penalize a badly executed shot.

The bunker used to be referred to as a hazard; an area of the course best avoided if you were looking to compile a good score. Unfortunately, the modern game has changed our perceptions of bunkers and how they should be presented. Golfers now expect to be provided with a playing surface, where the ball should lie "fairly" in a greenside bunker and able to play a shot to the green.

This, to a large extent, has been fuelled by the professional game where a player may elect to play and finish in the bunker rather than miss the green and be more heavily penalised in deep rough.

Whatever the whys and wherefores of this debate, there are still some fundamental aspects of bunkers that need to be considered:

Bunker size and shape

Depending on the style of golf course, age and maintenance regime, bunkers come in all shapes and sizes and there are no hard and fast rules as to which one is correct. However, a number of parameters apply:

• Where mechanical rakes are used the bunkers must be accessible, generally bowl shaped but with no appreciable face, which cannot be covered by the bunker bike. Obviously, bunker edges are finished off by hand but a mechanized bunker bike should adequately rake the majority of the bunker. The benefit of a mechanical rake compared to hand raking is uniform consolidation of the sand, an even depth of raking and speed of operation, which generally permits bunkers to be raked on a daily basis with limited staff.

• A new addition to the bunker maintenance tool selection are motorized hand rakes, a  hybrid of hand rakes and motorized riding rakes.  These lightweight hand tools offer the benefits of hand rakes, namely portability and precision, and the speed and ease of use of a battery powered unit.  They are especially useful around bunker edges or in bunkers where rock contamination is an ongoing issue.  They are also able to sift sand that is damp or whet, something that cannot be easily accomplished by manually agitated screen tools.

These shallower bunkers have performed well through this past summer, where extremely heavy rainfall has caused significant wash down of the faces and necessitated considerable effort to restore sand on the bunker faces, only to be repeated again the following week.

• The bunker should be shaped for ease of maintenance, including bunker face and any mounding surrounding the bunker. By providing turf rolled down the bunker face, it is easier to provide a consistent playing surface from the sand, only having to rake through one level. Also, contamination is reduced by not having an exposed bunker face. Invariably, contamination of the sand is a problem when golfers rake down the bunker face and, in so doing, expose stone and soil, which readily contaminate the sand.

• The base of the bunker should be shaped to collect water for drainage. A significant problem for bunkers is that of drainage, which must be high priority if the bunker is to remain in play through very wet weather.

Drain lines should be installed centrally in a drain trench, having a uniform fall of at least 1 in 200 to connect with a suitable outlet. Bunkers can be drained to a sump point or soakaway, but only if the lower soil profile has good drainage characteristics. There is little point in putting in a soakaway which quickly fills up and the area becomes a pond.

Traditionally, the drain trench is backfilled with clean, hard aggregate of 8-10mm diameter to within 50mm of the bunker floor. To prevent migration of sand particles into the aggregate, a blinding layer of coarse grit can be laid over the gravel, level with the bunker floor. Alternative methods of blinding are the use of upturned thatchy turf which creates an excellent barrier to sand infiltration into the drains, or one of the newer imports from the US (Sand Trapper) which creates a barrier to backfill contamination while allowing the sand to bed in.

• Within the bunker design, greenside bunkers should be set back from the green to reduce problems associated with sand splash. In theory, the bunkers should be shaped to allow the ball to be collected within the back two-thirds of the bunker so that any sand splashed will be collected in the bunker itself.

• The general shape and size of the bunker must be in keeping with the hole. It is at this point where the employment of a golf course architect would be beneficial to advise the club on a professional basis. Repositioning of bunkers needs careful thought and must be sympathetic to the original architecture.

Bunker sand

One of the most contentious subjects with bunkers is the choice of sand. There is no perfect formula and the final choice is generally a compromise between the material having suitable particle size, shape, colour, freedom from lime and cost. If a bunker is to provide a fair hazard, it is important that, when a ball lands in the sand, the surface is neither so hard that a ball bounces out or rolls, nor too soft that the ball plugs to an excessive depth.

The sand should be stable under foot and of a consistent depth. Specifications to meet the above requirements have been developed in the United States and trials carried out at STRI merely confirm these figures to be acceptable.

The recommendations state that sands are required to have 95% of their particles between 0.125 and 1mm diameter range, with the majority of particles falling between 0.25 and 0.5mm diameter. This is not to say that any sand which falls within this range will be excellent bunker sand.

What it does indicate is that sand falling within this range will have a better chance of being a good bunker sand rather than one that falls outside this range. Particle sizes larger than 1mm can have problems associated with blunting of mowers etc., and a large amount of particle sizes below 0.25mm are prone to wind blow and can restrict drainage movement.

Consistency of playing characteristics between the bunkers, which can only be achieved by using the same sand in each bunker and for topping-up purposes, is essential. Where different sands are used to top-up, this can lead to variations in playing characteristic and, therefore, consistency is lost.

It is important to appreciate that the quality of playing surface will vary depending on moisture retained in the sand, and playing characteristics will also change between winter and summer. I believe that there is no perfect sand which plays consistently under both wet and dry conditions.

It was interesting to note that pop-up irrigation heads have been placed in the bunkers at Wisley Golf Club and Carnoustie in order to try and achieve a level of consistency. This really is taking the concept of bunker management to its ultimate.

I also believe that, where new bunkers are constructed, the new sand must have time to 'bed-in', i.e. settle and weather, in order to produce the desired playing surface.

As a point of reference, I visited a golf club a few years ago where they had embarked on a bunker reconstruction program. Three years into the program, members were beginning to question the quality of playing surface which, in some cases, was very good, in some, somewhat indifferent and, in others, rather poor.

Having analyzed each bunker in turn, it was clear that the quality of the playing surface varied with age of construction. Those bunkers constructed within the previous twelve month period were considered rather poor, the sand being loose and fluffy. Those bunkers which were mediocre were aged between twelve and eighteen months, and those bunkers which were thought to have a good playing surface were eighteen months plus or the original bunkers which had a firm base.

Golfers must, therefore, be patient with the restoration program being undertaken. In an ideal world, a bunker renovation program would be carried out within a two to three year period to try and maintain a level of consistency.

Maintenance

Having selected the right bunker sand, and allowed the material ample opportunity to bed in and weather, the most significant factor affecting the quality of playing surface is that of maintenance. Depending on the sand selected, the bunker sand should be placed no more than a consistent 100mm firmed depth over the whole bunker floor. Where a sand face is provided, the sand on the face itself should not exceed 50mm. The ideal playing surface provides a sand which is slightly moist and well firmed, but with the immediate 25mm of surface raked-over into which the ball will sit.

One of the greatest influences on playing quality is the level of maintenance applied to bunkers on the course. Courses where bunkers are tended on a daily basis, providing consistent depth of sand, quality presentation, etc. have fewer complaints about the playing surface compared to those where the bunkers are raked once or twice per week.

If, as a club, you are experiencing excessive complaints from the members in respect of the quality of the playing surface, the first point of reference should be frequency of raking and not choice of sand. If infrequent raking is the norm, try raking bunkers daily for a period of two weeks and gauge members' comments after that period.

Manpower is often a limiting factor to raking daily, but the trial period may prove that there is little wrong with the choice of sand and, if members want better bunkers, there may be a need to employ additional manpower to achieve the level of performance required.

If, however, the increased level of raking has not changed the playing characteristics and uniformity of playing surface, an alternative sand may be appropriate.

Conclusion