Is it true? Can better quality irrigation water improve the turf conditions on a golf course, thus enhancing the playing surfaces? It seems logical enough, but how? Mother Nature provides the best quality water for almost any agronomic use, but unfortunately, she does not water our greens nearly enough. Therefore, most golf courses have an irrigation system. Those systems get their water supply from a wide range of sources, some good and some not so good. What kind of problems can poor water quality lead to on a golf course? Many. What kind of solutions are available to address those problems? A growing list.
The recently released USGA Water Conservation Playbook (see QR code) states that water use on golf courses has been reduced by 30% since 2005. It sounds impressive and we certainly must continue that trend, but as more courses are forced into using reclaimed water, the priority on water conservation is forcing water quality to take a back seat. The inherent problems in reclaimed water include higher salts, minerals and organics. They cannot be removed biologically at the wastewater treatment facility and so are passed on to the superintendent to deal with. (Note: Every water source, from wells to surface water to municipal water, has some of the same problems, but to lesser degrees).
How does that affect our grass? First, one of the most obvious things is a water infiltration rate reduction. The added impurities increase the surface tension of the water, which means it tends to sit on the surface and evaporate, never reaching the thirsty roots. Second, an increase of soluble organics can become food for undesirable microorganisms or can cause the formation of biofilms that add to the thatch layer. Third, probably the hardest issue to recognize, but potentially the most problematic, is the salt and mineral deposition on the sand particles in the root zone of the putting greens.
Much is written about how to select the proper sand for the root zone layer of a USGA putting green. Performance parameters for drainage, capillary porosity (water retention) and Coe icient of Uniformity (particle size) are important to obtain the desired performance on the surface of the putting green. As the high salt and mineral irrigation water percolates through the root zone, it begins to leave deposits, similar to what happens in your hot water heater. Scale forms around the sand particles and they begin to grow. It is a slow process, but eventually the root zone sand is no longer within USGA specs, which means it loses its functionality. That affects playing conditions. At some point, the green will need to be rebuilt.
There isn’t one magical treatment to address all the various water quality issues, and each will add expense to the maintenance budget. Without addressing the principal cause, aerification can help with the infiltration problem by opening the surface and allowing water to get down to the roots. Organics can be reduced by microfiltration or ozone. Microfiltration simply filters out all the particulate matter, while ozone is a halogen that will burn up soluble organics and is also a biocide that will reduce the microbe population. Removing salts and minerals is more di icult. Reverse osmosis will get you closest to Mother Nature’s rain water, but it is expensive due to the membranes and the high pressure that is required to push water through them. It is also wasteful. Depending on the recovery rate of the system, it may dump 50% or more of the supply flow down the drain as reject. Acid injection into the irrigation water stream is another method to try to control salts and minerals. It does not remove them like reverse osmosis, but rather attempts to keep them in solution longer so they do not form deposits, which allows them to flush via drainage. There are other proprietary chemicals that can be used directly on the greens to try to dissolve the minerals and flush via drainage.
The challenge for the superintendent is to conduct a cost-benefit analysis. It is often di icult to put a dollar figure on improved conditions. Therefore, many superintendents will hire outside consultants to conduct an irrigation system audit within the entire facility to help them identify the problem areas and find potential solutions. It then becomes one more added expense due to poor water quality.
Most superintendents would agree that better water quality will lead to better turf conditions. How to obtain improved water quality in the face of increasing conservation demands and escalating costs of treatments and chemicals is the challenge we are asking our superintendents to deal with. It is never easy to replicate Mother Nature.
Brad Crookshank is a member of the CDGA Green Committee. He has been a CDGA Blue Coat since 2019.
