This November, we will embark on a complete bunker renovation using the Better Billy Bunker (BBB) I talked about in the past. See the post on September 24 for a video that explains this. There are many ways to build a bunker in addition to the BBB. Some install drainage and simply put sand right on top of native soil and gravel. This leads to contamination very quickly. Others will install a textile liner over the soil to prevent contamination. In both of these cases, you don't get the advantage of better drainage and less washouts as you do with a gravel layer on top of the soil on the bunker floor. Liners will also get clogged, slowing the movement of water into the drainage. Cost and budget are the main factors in determining the which method to use. Below are two other relatively popular options depending on what part of the country you are in. Our 96" rain demands we have excellent drainage, making the BBB our best option. In addition, the fact we already have that 2" gravel layer under the current liner also makes it the most practical and economic choice.
In some areas of the country, Superintendents line the bunker floors with sod. Many courses have recently completed or are in the process of completing bunker renovations in which this method is employed. As you can see, the process is relatively simple. The floor of a bunker is lined with sod with the exception of the drain lines to maximize the flow of water through the bunker sand. The sod is laid down and given time to take root which at this time of the year can vary between six to eight weeks. Once the sod is firmly rooted, the grass is scalped down to stress the turf and/or sprayed with round-up, followed by smothering with new bunker sand. The thatch layer from the sod is essentially what serves as the liner that keeps unwanted rocks, gravel and silt from contaminating the clean bunker sand.
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| The above is an excerpt from a fellow superintendent blog, TPC Snoqualmie Ridge in Washington State |
Another popular option is what's called Capillary concrete. This is very effective and a great product but very time consuming given that concrete is poured in the bottom of every bunker. This requires a lot of equipment and mixing. The concrete is porous and water moves easily through it, working like a Better Billy Bunker. My friend, David Stone at The Honors Course in Chattanooga TN recently renovated many of their bunkers this way.
All options are effective and every Super has their own thoughts on which is best for their facility based on different priorities and factors. What works best at one facility may not at another. This is a common theme in many aspects of golf course maintenance.