How Does XGD Work?
Ahh, what a question. Where do I begin to answer that question?
Well for starters, let me just say that most soil scientists will readily admit they really don’t have a handle of how “groundwater” moves through soil. They have ideas/theories, but they can’t explain everything. I am not a soil scientist, but I have been diagnosing turf drainage problems for more than 20 years now, so I have a pretty good idea through experience how to handle it.
The key word here is “groundwater”. When most see a drainage problem they generally think of how surface water flow has caused their problem, and in doing so install a catch basin in the lowest point of the problem, believing everything is caused by surface flow issues. When in reality it is most likely caused by groundwater moving through the soil then hitting some impermeable material such as rock/heavy clay which forces it to the surface simply due to path of least resistance.
A push up golf green is generally not that different. Heavier soils were used in this type of construction to hold the moisture, because “automatic irrigation” wasn’t a buzzword yet, so when it did rain they wanted the green to stay as moist as it could, for as long as it could because it was difficult to irrigate simply. This created a bathtub and a high “groundwater table” intentionally. A subsurface drainage system like XGD is designed, through it’s pipe spacing and pipe depth to lower the “groundwater table” and create more open pore space in the upper soil profile so that when it does rain, there is some water holding capacity in the soil through the pore space, until all the pore space fills up and “field capacity” is reached. Once this occurs, the green will drain almost immediately, which basically allows oxygen to be drawn in to the mostly now empty pore space and give the green a fighting chance in the hot,humid periods of the year.
Now that is a very simplified version of what is occurring, but I wanted to conclude with this point that no one has all the answers to drainage issues, but this common sense approach has served me very well over the course of my career with TDIGolf http://www.tdigolf.com/ and XGD Systems.
Over and Out, Poor Old Dirt & Grass Farmer