Bunkers – Do you know what lies beneath?

By Brady Wilson, General Manager and Kelly McCaffrey, Golf Course Superintendent – Ak-Chin Southern Dunes Golf Club

“No, no, nice shot… right on the beach.” This Caddyshack reference can be heard on almost every golf course, every day when someone in the group finds a strategically placed bunker with a somewhat errant stroke.

But have you ever asked what actually goes into making that bunker play so hard; or so good, depending on your perspective?

This past summer, Ak-Chin Southern Dunes Golf Club did a complete bunker renovation and while our golfers now will experience better sand conditions, when you “redo” almost 400,000 square feet of bunkers, you become knowledgeable real fast in the details of a sand bunker.

Everything starts with drainage in a sand bunker. Drainage is designed to get water out of the bunker and get excess water into the course’s main drainage system ASAP. Many challenges can come from poor or no drainage in a bunker, most of which is playing conditions can be inconsistent because damp sand can play a lot different than dry, fluffy sand; and if contaminated, can almost play like hard pan.

In a bunker’s subsurface, down to the natural earth, we dug small channels or small trenches, then filled them with 4 inch, perforated pipe (so water can percolate into the pipe from above), and then covered the pipe with pea gravel to level the trenches to the subsurface. These pipes are spaced out according to a USGA standard specification and are eventually connected to the course’s main drainage system (catch basins, sumps or mainlines).

If the irrigation lines are the “arteries” of a golf course from the pump station, then drainage lines are the “veins” of a golf course. But while getting the water away from the bunker ASAP is important, it is only half the battle with maintaining quality bunker conditions.

Bunker sand is very technical in nature with its engineering. Angularity of the sand particles and its hydrometer rating (percolation rate) are all tests that you can get on over 50 different varieties of bunker sand. Choosing the correct bunker sand for your individual facility is very important; and making a long term commitment to a supplier so that you know you can always get the same, pure form of bunker sand is imperative.

One challenge we had was that decisions had been made in the past to change bunker sand varietals without removing the prior sand. This caused for an odd and inconsistent mix of sand from bunker to bunker for all 109 of them at Ak-Chin Southern Dunes.

Finally, once you have your sand of choice, you have to have a barrier of some sort to prevent the subsurface, natural earth, and the pea gravel covering your drainage from intermixing or “contaminating” your pure bunker sand. 

There are many choices in the market for this barrier, but we chose to go with a “spunbond” fabric liner that allows water to permeate through it. This liner is tacked down into the subgrade with 12 inch stakes and ensures that we keep the earth and gravel below and the bunker sand up top.

A large amount of our bunkers at ACSD did not have liners or drainage installed in them at all during the initial construction and some of the existing drainage and liners were failing. After a summer of renovations, our team can ensure you that all bunkers are properly drained, lined and a new, pure form of bunker sand has been installed, resulting in great sand bunker playing conditions for the foreseeable future.

With proper maintenance, our new bunkers should last 25-30 years; giving you plenty of opportunities to respond to your Caddyshack hecklers with a “Sandy” from Grease.