Irrigation Technology - Nozzle Selection

Irrigation components and technology are in constant change. Manufacturers are continually upgrading software, hardware, and everything in between. As we charge ahead through the hot summer months one of our main focuses is tweaking the performance of our irrigation system. In fact, about 70% of the management staff's daily responsibilities will involve water management. One way we can make a simple and economical change to a problem area is by upgrading an irrigation heads nozzle assembly, one which produces a more uniform water distribution pattern. As opposed to a home lawn situation where pop-up heads throw water 10-12 feet at 4-15 gallons per minute, most of our irrigation heads throw 65 feet at 30 gallons per minute. The more GPM (gallons per minute), and throw radius, the greater the challenge it is for the nozzle engineers to produce uniform spray patterns. This is where the coefficient of uniformity comes in. It is defined as a measure of the hydrodynamic behavior of the system. As we research different nozzles, we use the CU as our basis for what to select. The lower the CU, the better coverage we will achieve. Throughout the past 7 years we have dabble with various combinations of nozzles and have found that while nozzle selections is extremely important, the initial installation of the irrigation system plays and even more important role. I am speaking specifically to head spacing, You see, our head spacing is supposed to be 65 feet but with the different widths of golf holes, it made it difficult for the irrigation designer and construction company to get even spacing between heads. This means that we have some areas that have a spacing of 45 feet, while other areas are 75 feet. This creates several challenges when trying to produce consistent playing conditions. In the end, we may be able to move some heads around in order to produce a more uniform coverage but in many cases we utilize nozzle combinations to provide some relief. As I have stated in the past, over the past year we have made an investment (about $5,000) in reducing our water usage while improving our uniformity. We have replaced nozzles in over 800 heads with what I will call "year 2000" technology, much better than the 1992 technology but yet not perfect. According to the water coverage software we should be increasing our uniformity (and therefore reducing our usage) by 15%! After a few hot days this year I can already see the difference and hope to continue this nozzle conversion throughout the season.