Dealing with Interference

Last month I talked about the need to water accurately. Accomplishing this requires knowing the precipitation rates of your various sprinkler/nozzle combinations. That works great in theory, but there are other factors out on the golf course that will always require you to adjust your irrigation schedule. One of those, although not effecting the time to water, does affect the distribution of water being applied, and that is stream interference.

Until the early 2000s, stream interference was never a concern. Before then, sprinklers were not consistent in how they threw water. Although they were the same model sprinkler and nozzle, the throws were still slightly different. How the sprinkler is manufactured, as well as sprinkler spacing, leveling and grade all affect how the water stream leaves a sprinkler. In the past the sprinkler spacings were consistent, but would certainly vary a bit throughout the golf course or a hole even when staked at the same spacing. The result was that if you ran two sprinklers either beside each other or across from each other – such as in a double row fairway configuration – rarely would you see the streams of the sprinklers hit each other as their arcs bypassed each other. If the sprinkler was not set to grade or not level, the chances of stream interference were reduced even more.

With today’s highly engineered and precisely manufactured sprinklers, better and more accurate staking and installation, as well as increased maintenance staff attention to sprinklers being level and at grade, the incidents of stream interference on golf course irrigation systems have increased dramatically. Don’t think so? All you have to do is go out and look at your sprinklers operating. Correct nozzle/sprinkler spacing and maintained sprinklers result in consistent water throws. With the installation of three-row, five-row and wall-to-wall systems, the number of sprinklers on today’s golf course has substantially increased and so has to the stream interference.

Why is stream interference even an issue? As sprinkler streams hit each other, the water stream is interrupted and the water does not end up where intended.”

Why is stream interference even an issue? As sprinkler streams hit each other, the water stream is interrupted and the water does not end up where intended. This effects the uniformity of the sprinklers and results in poor coverage. You may not think it is a big deal, but if you see it occurring out on the golf course, you will be surprised at how much it interrupts a sprinkler’s throw. Stream interference is repetitive as the sprinkler rotation speed doesn’t change nor does it alter your schedule that much, so the stream interference continues each time the sprinklers operate.

The good news is if you recognize you are having stream interference, today’s golf course irrigation control systems allow you to easily schedule around it. What you have to do is set up your schedule so sprinklers in close proximity to each other do not operate at the same time. For example, you may have a triple-row system broken into three scheduling areas, such as back nine fairways left, back nine fairways right and back nine middle sprinklers. These sprinklers would operate green to tee in sequence down the fairway. If you are running multiple sprinklers at a time, say one per program, the three sprinklers left, middle and right may be operating at the same time or two or three in a row, left, right or middle. That will result in stream interference. What you need to do is break up those areas scheduling-wise so no sprinklers beside each other will operate together.

This may sound easy, but it takes a great deal of thought to have your control system not have sprinklers operating beside each other. You need to write separate programs that keep the sprinklers spaced apart and the water spread throughout the golf course. On systems with ins and outs at the fairways and/or the greens, then it holds true for both the ins and the outs separately.

In today’s water conscious age, it is important to be as efficient as possible with your water use. Preventing stream interference is another way to save water you probably never thought of, but it’s easy to when you eat, drink and breathe irrigation.