The Importance of Positive Grade to Drainage Installations
I wanted to address some alternatives to our subsurface drainage process, more specifically to our greens drainage operation. This topic also ties in well with the importance of the layout of a drainage system, be it on a green, fairway or a farm field.
I always stress to our potential clients that our drainage process is a significant capital investment for any type of facility, and in return for that investment you should receive some kind of indication that it will be productive for the long term. At XGD Systems we accomplish this by providing positive grade on every single foot of our installations.
Verbiage like “close enough” or “that will do” are not tolerated in our XGD vernacular. If an installation is made such as installing our 2″ pipe flat for several feet or more, and/or a grade error is made +or- even a half inch or greater is made, an installer might not even blink an eye, except here at XGD. When that type of installation error is made the pipe might continue functioning in the short term if there is positive grade on the pipe or system behind it. But my take home point here is “the short term”. As the drainage water flows through that grade error it does so very slowly and may even come to a stop for a period of time. As the water is moving so slowly and stopping it allows the suspended solids and fines in that water to drop to the bottom of the pipe and begin to build up and start to impact negatively on flow velocity at the grade error and begin to plug the pipe completely if the error is large enough. An apt comparison to this might be the silt in pond water slowly dropping to the bottom of the pond or creek once the turbulence of a rain event subsides. This problem is also compounded by the fact the flow velocity is further reduced for the long term and the suspended solids and fines will not flush themselves out of the system when they do accumulate at grade errors.
At XGD, I often refer to our installers as extremely anal about their grade and their layouts. This is an advantage of our open trenching process. We continually check and ensure positive grade, and I call it part of the “culture” here at XGD. Other greens drainage alternatives using tiny pipes and ropes are vibratory plowed in to the greens subsoil and cannot be checked for grade. Really? They counter this argument with the fact they always run their laterals with the slope of the green, which in essence is admitting, without even knowing it, that their drainage system layouts are poor, and don’t cut off or intercept subsurface gravitational groundwater or surface water flow, instead allow this water to run between their laterals.
Well, okay then, they can keep grade on their small pipe(unforgiving to even tiny grade errors) or ropes on their laterals by installing parallel to the greens slope. As I explained, that may be true but inherently foolish for system efficiency, but what about keeping positive grade on their mainlines. If your mainlines grade is compromised, then I don’t care how much positive grade you have on your laterals, water will not flow through a plugged pipe, nor will it flow outside of the pipe and use the sand backfill as a backup and continue flowing around the grade error. If it does so, it will back up the entirely passive drainage system even more and that type of time lost in emptying the greens soil profile of useless groundwater may be the difference between turf loss and a green with proper air and water balance.
I believe it was Donald Ross said that “careful, thorough drainage” is the most important component to have for proper greens health, and we couldn’t agree more. Our installations have stood the test of time for 20 years in our oldest installs. We consider that longevity significant and a genuine long term return for a capital investment for any type of golf facility. So please consider that when hiring the local contractor who can do it all. Is that type of short term gain worth it to your club for the long term. I liken it to installing a band-aid on the problem when you could have opted for the one time expense of open heart surgery for your treasured putting surfaces.
Regards, Poor Old Dirt & Grass Farmer
RIP Levon Helm whose later album “Poor Old Dirt Farmer” was borrowed for my blog handle.