So you don’t have the funding to make major changes to your irrigation system due to the course’s financial condition or other priorities. What can you still do to make your system perform better? I suggest analyzing the sprinkler/nozzle/spacing combinations for your greens, tees and fairways. This can quickly improve the system’s overall performance.
Take sample sprinkler spacings (row to row and sprinkler to sprinkler, as well as across the green – not just around it) for each feature (greens, tees, fairways). Record the sprinkler manufacturer, model and nozzle at each location. Determine the pressure regulation setting for valve-in-head sprinklers (setting or spring color) or block electric valves if pressure regulated. Measure operating pressures with a pressure gauge installed in the closest quick coupling valve to the sprinkler(s) you are looking at. Locate the performance chart for the sprinklers on your course either on the Internet or in your files. Cannot find one? Call your distributor.
Armed with this data, look at the performance charts at the regulated pressures of the models and nozzles installed at each location. Look at the throw of the sprinkler and compare it to what you measured in the field – is it the same, shorter or longer than the sprinkler spacing? If the sprinkler is throwing water a few feet longer than the spacing, that’s a good thing. If it’s short by a few feet, that may not be good depending on the sprinkler model. Make sure there is water being applied right at the sprinkler by the overlapping sprinkler to ensure there are no dry spots that will cause you to overwater. If the sprinkler is throwing water short or long by more than 5 feet, then its performance can be improved. A smaller or larger nozzle could be installed, but keep in mind that having lots of different sprinkler model/nozzle combinations makes it harder to manage your irrigation schedule and system. A better solution is to fix the spacings so the sprinklers are throwing within the zero to 5-foot range of head-to-head coverage.
Today’s sprinklers do a great job of putting down water uniformly. The same cannot be said for older sprinklers. If you look at the history of golf sprinklers – we will only go back to the 1960s – putting down water uniformly was not the priority. The priority was throwing the most water as far as possible. Think back to Rain Bird 81B’s or Toro 690’s – high pressure, lots of distance, lots of water (100 psi, 108 foot radius, and 82.2 gpm). Through the ’70s, ’80s and ’90s, sprinklers were improved by the major manufacturers (Hunter entered golf in 1989) on a regular basis. In the mid-1980s, you started to see uniformity become more of a design consideration. Cup tests to measure uniformity started around 1987. With each enhancement, sprinklers got better at uniformity.
If your sprinklers are decade old, changing the them alone will improve irrigation system performance. If you can adjust the sprinkler spacings, too, the performance will improve even more. However, replacing sprinklers and/or moving sprinklers are still expensive undertakings. An inexpensive option is to install third-party nozzles. These are custom-designed nozzles for the major manufacturers various sprinkler models and series to improve uniformity. These replacements are less than 10 percent of the cost of sprinkler replacement. If your system utilizes potable water, the nozzle replacement costs may be underwritten by the local water authority as part of a conservation rebate.
If all you have are labor hours, make sure your sprinklers are level and set to proper grade to enhance performance. This applies if you have money, too, and even if your sprinklers are relatively new. A sprinkler installed on a slope, or having the stream deflected, will lower uniformity much more than poor spacing or bad nozzles. Make sure the sprinkler’s throw clears the turf when it pops up. Older sprinklers have short pop-up heights (Toro 690’s, 2.25 inches) as compared to newer sprinklers (Toro 855S’s, 3.25 inches), for example.
Getting a new irrigation system has many benefits, but new systems have become extremely expensive. Even just changing the sprinklers is an expensive undertaking. There are alternatives such as nozzle change outs available as long as your infrastructure is intact and not failing on a regular basis.