One of the important questions about irrigating turf and landscape is “How do I find out how much water our irrigation system applies?” The best way to do that is with a rain gauge.
You can set your rain gauge out into the landscape – whether you have an in-ground irrigation system, or whether you’re using a hose and an above ground sprinkler. With an in-ground system, take some flags and flag where the irrigation heads are located. Then, stick the rain gauge out in-between the flags and run the system for a normal amount of time. You’ll need to do this several times across the landscape to determine the precipitation rate for the whole zone.
For example, if we ran this irrigation system for 30 minutes, and we find that there is ½ inch of water in the rain gauge, we’d know that it’s necessary to run the system for an hour to apply a full inch of water.
The next thing that you can do is to get a bunch of catch cans like this and spread them across the landscape. You’ll need nine or ten per zone. After running the system, you won’t be able to tell how much water comes out, but you’ll have an indication of whether one area (one sprinkler) is applying more water or less water than another sprinkler.
So, we’ve set our catch cans out, and we’ve collected our catch cans. Remember, the catch cans won’t give us an indication of precipitation rate because they’re not rain gauges. And, they have a much larger surface area than a rain gauge. But we can look at the differences between the catch cans to find out how uniform our system is.
If we take this catch can and pour it into a rain gauge, we can see that there is about ¾ of an inch. And if we take another catch can and measure it, there is about 1 ½ inches of water. So, the area of the irrigation zone where this catch can came from is getting twice as much water as the area from where the other catch can came from.
That means that this area of the yard is getting twice as much water. This can indicate a problem in the area that is under irrigated, or a problem with the area that is over irrigated. It’s best to contact an irrigation professional to determine if there is clogged valve or a design issue that’s causing a problem. For help, you can contact your local irrigation contractor or your local water company.
This feature story prepared with Rodney St.John, Kansas State University Research and Extension, Turfgrass. For more information, visit your local county extension office or visit our website at KansasGreenYards.org.