Abstract: Settled areas on golf courses create water pockets and dangerous conditions for distracted golfers. Here’s a few methods to fix these problems.
Golf fairway depression is not a psychiatric disorder. It’s not caused by a chronic inability to nail a three-metal. Golf course depressions are turfed areas that are several inches or more below the surrounding grade. These depressed areas can be hundreds of feet long. They create depression in golf course superintendents or golfers.
Settled areas occur when subgrade material under golf course turf decomposes or relocates. This void is filled with soil from above the void.
The primary cause of settled areas is the decay of organic fill. It’s created by improper golf course construction. Golf course contractors are known for creative disposal of organic debris. In the past, environmental regulations didn’t specify where stumps, sod, and other organic debris could be buried. Off-site disposal costs are expensive, so many golf contractors buried organic materials under golf fairways.
The worse case of organic decay I’ve seen was under a top-tier golf course in the Northeast. A not-very-experienced golf course builder constructed the course in 1967. Faced with a huge volume of stumps and wood-waste, he buried this debris wherever he could, usually when the golf architect wasn’t looking. He chose the location of a golf green as a dump site. Gradually, the golf green settled and this began a yearly ritual whereby the golf super removed the green sod. After installing a few shovels of green mixture, he returned the sod.
We were asked to fix the problem. While doing a bunker renovation on this course, I asked a golf course shaper to view the settled green. He took one look and said, “I’ve got the cure.”
He moved his large excavator to the edge of the green (on plywood so no damage occurred). We marked out an area 20’ by 20’ on the putting surface, and he swung the big bucket around. Much to the horror of several members lounging on rocking chairs, he dug down about ten feet and removed three huge stumps. He eventually removed three truckloads of organic waste, concrete, and assorted other junk. We filled the void with clean gravel fill, added a 14” layer of greens mix, and installed new sod. The green is in play today and everyone has forgotten about the settled area.
Deep freezes in the Northeast can relocate large rocks creating settled areas. The rocks that cause these depressions usually can be removed and the void filled. Large rocks or ledge require localized filling of voids.
I wrote the following specification for a golf course with thirty large settled areas located in fairway and rough areas. The contractor buried wood-waste in fairway and rough areas, and these areas settled a few feet. Someof the settled areas are 100 feet long and 50 feet wide. The settled areas include decomposed organic material, or compost, and solid wood waste (stumps). I proposed to mix the compost with sand, creating a stable fill material. The course has a cheap supply of drainage sand nearby, other fill can be used. The solid fill will be removed and transported to an off-site organic waste facility.
- Stub all irrigation within work zone. Use a large excavator (Cat 312 excavator) to open up the settled area. Use plywood as needed. Go wide on the excavation to include some bordering areas. Mix and ompact the decayed material with the excavator bucket. If possible, compact the fill with an excavator mounted vibratory plate compactor.
You’ll have a final grade 1-2 feet or more below final grade after mixing. Apply a geogrid fabric, or HDPE neting, on top of the compacted fill. This product come in rolls and it provides an integral connection to the fill. Install a layer of geogrid on top of the subgrade material, add 6″ of 3/4″ stone, then sandy fill to grade. Install topsoil 6″ over grade to allow for any settling and seed/sod. Add a few mounds and golf forms so the fill doesn’t look like a burial pit.
Golf course depression can be cured. You don’t need Prozac or Welbutrin. The right fix will increase your golf course playability.