Sooner or later, every golf course and its superintendent faces rebuilding or renovating its sand bunkers. When this time comes, course management should consider whether its existing bunkers are still doing the job the architect intended. With new technology in club and ball design, some fairway bunkers do not really come into play any longer. Therefore, these elements are not a challenge to lower-handicapped players, and they penalize higher-handicapped players.
Let's look at each step involved in renovating a bunker.
Step 1: Determine the reason for renovation.
On any course, you'll eventually need to renovate all your sand bunkers, although the reasons for renovation may vary from one hole to another. For example:
Sand may be contaminated
Edges may be deteriorated
Construction may be poor
Drainage may be lacking.
In many cases, one or two of these problems may be incorporated with one or two of the others. So you typically don't have just one problem with which to deal.
Old-style sand-bunker designs incorporate a relatively flat base with sloping grass banks extending down to the sand. These bunkers are easy to maintain and typically have few problems if you've installed adequate drainage.
In newer bunkers, however, the traps are shallow and elevated for easier visibility. Sand is flashed up the bank, which can create erosion problems. Erosion, in turn, leads to sand contamination and washouts that require hand labor to shovel sand back on the bunker's face after heavy or prolonged rainfall. In some parts of the country, such repairs can become a large expense and reduce the life span of bunker sand. This is especially true of poorly constructed bunkers.
Step 2: Contact a qualified architect.
Before you consider any major bunker relocations or renovations, make sure you involve a qualified architect, if possible. Bunkers influence playability, as well as overall interest in and the mood of a golf hole. Few superintendents possess the same artistic ability as the architect.
A good architect provides a great amount of consideration in determining the proper location of bunkers to equally challenge all players. Bunker placement can set up a hole to provide penal, strategic or heroic measures. Make sure your course has not become outdated in bunker placement before renovations occur.
Step 3: Remove the sand.
Remove and discard all old sand or use it on other areas of the course. Sand that is contaminated with organic matter, soil or other large particles has no place in sand bunkers.
Step 4: Identify the original bunker edge.
This can be a challenge on some older courses. The original shape of the bunker can be several feet away from the existing edge. You can identify the old, original sand--which will follow the original contour of the bunker--by probing or digging. One superintendent told me he found some of his green-side bunkers were 10 to 12 feet off of the original bunker design. Of course, such differences have a great influence on the way golfers play the hole.
Step 5: Dig out the original shape.
Once you've established the original shape of the bunker, use a mechanical loader, such as a skid-steer loader, to dig the bunker back to the original shape.
If the bunker is a green-side bunker and you don't have to remove much edge, it's likely that sand has accumulated on the green from sand shots blasted toward the cup. Several feet of sand can accumulate in this area given enough time. If this is the case on one of your bunkers, you'll have to take that section of the green down to its original level. In doing so, you'll solve several other problems on the green that you may not have attributed to your bunker's deterioration. For example, this buildup of sand typically causes the bunker's lip to gradually deteriorate. Plus, it causes turf to thin out in this area due to the droughty conditions the sand creates. Thus, to solve the problems, you must take the accumulated sand down to the original soil level. You'll need to first remove the sod, then remove the sand and then replace the sod.
Admittedly, removing a significant layer of the sand may give a very different look to the hole--one to which some golfers may object. So you should give some careful thought to this area's renovation. You may even need to add soil before you relay the sod. (You can avoid future sand buildup around green-side bunkers by resodding every 3 to 5 years. Simply remove the old sod with the sand accumulation and replace it with new sod.
Step 6: Consider water movement into the bunker.
Water movement is an important concept to keep in mind when working on bunker faces. You can avoid surface runoff into bunkers by building a lip 6 to 12 inches high or installing an interceptor drain at the top. This type of drain intercepts surface water before it reaches the bunker. To install it, use a 4-inch flexible ABS perforated pipe in a 6-inch-wide trench that is 16 to 18 inches deep. Fill it with 3/8-inch pea gravel. You then can connect this pipe to an existing drainage system. Allow the existing turf to grow over it naturally. Do not lay sod over the ditch.
Step 7: Address edging problems.
Bunker faces are not the only aspects of a bunker that you must address during renovation. With the advent of mechanized bunker rakes, many courses have experienced problems arising from their misuse. Specifically, the mechanized rakes tend to push sand to the outside over the edge. In so doing, it becomes difficult to tell when you are inside the hazard or outside of it.
Therefore, you must define and shape the fairway side of the bunker. The edge should be 4 inches below grade to allow for sand replacement. It is important that the back and sides are flush with existing ground level. This facilitates surface drainage and eliminates a vertical lip that can interfere with a golfer's swing. After all, sand bunkers should offer the golfer a chance to advance the ball toward the hole.
Step 8: Re-establish bunker edges and banks.
You can use two methods to reinstall a well-defined border, which gives the bunker its final shape and aesthetic appeal.
Method 1: First identify whether your bunker is on a flat--or relatively flat--plane. If so, you can use strips of plywood or metal sheeting to support banks during turf re-establishment. Obviously, this method works best where your bunker needs little support.
Method 2: For bunkers with large elevated capes and mounds, follow these steps:
Fill burlap bags about three-quarters full with topsoil.
Lay the burlap bags out to establish your edge.
Fill between the bags with soil.
Place sod on top of the bags, laying the sod over the rounded edges of the bags.
Perform final edging after the grass has grown and the bags have decomposed.
You can mold and move the burlap sacks to provide the precise, desired effect of the bunker. In time, the burlap deteriorates. In the interim, it does an excellent job of protecting the bunker from soil washing into the bunker.
Step 9: Install appropriate drainage.
Good drainage is essential for all areas of the golf course. Sand bunkers are no exception. Good drainage, in fact, is probably the most important step in bunker renovation. After all, a bunker that allows sand to wash from its faces is a bunker with a short sand life due to contamination.
If necessary, install a smile drain (4-inch ABS perforated pipe) at the top of the slope to intercept runoff.
Step 10: Install the sand.
The USGA established bunker-sand guidelines in 1974. These guidelines recommend sand particles between 0.25 and 1 millimeter that are angular in shape. (This is the same recommendation for greens construction.)
Before buying replacement sand, send a 1-gallon container of each type of sand you are considering for use to a soil-testing lab. The USGA bases its guidelines on laboratory tests, practical work and experience.
Therefore, it's important that you evaluate the sizes, shape, purity, color and composition of the sand you may use. After all, a sand's particle size significantly determines its playability. And having the correct particle size in a green-side bunker prevents larger particles from sitting up on the turf surface and interfering with ball roll and damaging greens mowers.
You also must check each load of sand to make sure it is uniform and of the same type you originally selected. Make sure trucks were clean before sand was added and no foreign material was left in them.
With increasing costs and budget restraints, any labor-saving procedure you can find is beneficial. And renovating your bunkers using the preceding guidelines can help lessen future maintenance needs.
Stabilize soil to discourage contamination Stabilizing soil on the face and bottom of sand bunkers can help prevent sand contamination. Several products are currently available with various coatings. Whether they are economical and perform the job for which you need them varies from one site to another.
Several types of woven fabric also are available that help form a barrier between soil and sand. Unfortunately, the failure of these units due to the misuse of mechanized bunker rakes is common. Therefore, these fabrics have been unpopular with some superintendents.
Another option is a new material of synthetic polymer and limestone screenings. You blow the material into place, much like Gunite is sprayed onto swimming-pool walls. Upon curing, the material becomes a dense undercoating, capable of resisting environmental extremes. Although the product's longevity is not yet proven, it looks promising.