I get asked a lot of questions regarding our bunkers. Here are some answers to some of the questions.
Why don't you just add more sand? The current sand is contaminated with silt and gravel. Silt is the biggest reason the bunkers don't drain well. Adding new sand wouldn't do a lot in this case because proper drainage is our biggest concern.
Can you just take the old sand out and put in new? Unfortunately the silt has worked its way down to the drain tile and has clogged up the perforations in the tile. In some cases socked drain tile was used and the sock is clogged up with silt. The existing tile was also shallow has been nicked with the bunker machine and silted sand has entered the tile.
What does the bunker renovation entail? Our bunkers are getting completely overhauled. As mentioned before the old sand is removed. We also strip about 3-4 feet of grass around the bunker, this helps define the original size and shape. This grass will be discarded because it's inconsistent and replaced with new sod. The old drainage system is removed and also discarded. After altering the shape, the sub floor is re-worked to create a floor that is flat, free of rocks and slopes slightly to future drain lines. The next step and the most important step is a new drainage system is installed. Adequate drainage on the entire golf course is important, but in bunkers it's critical. As we replace the grass that was removed around the edge with sod, we will also be lining the entire bunker with sod. I have talked with several people that have done this and it's inexpensive and very effective.
The New Drainage system
The new drainage system is unique, the pipe size is smaller than the old system but more drain tile is added. There are several things I like about this drain tile. The holes are a lot smaller than the old conventional drain tile. Unlike the old perforated tile that was back filled with pea stone, this particular tile is actually back filled with sand and is installed deeper than the old system. I really like this because it eliminates the risk of pea stone contaminating the sand. Another benefit of this type of system is the sand can easily be removed and replaced if needed and the tile itself is much easier to work on. The new drain tile has spiral corrugations inside and out and fittings screw on snug to keep sand out. Also with a spiral interior water flows through it faster which is very important in bunker drainage.
The video link below will help explain why a bunker renovation is necessary
USGA Bunker Video