Though landscape and turfgrass received good rain showers in July, now it's a hot, dry August. At this time of year, it's especially important to properly use the natural resource called "water."
How many times have you seen water from a sprinkler system running down the street during the day, or even during a rain shower? What about a sprinkler head broken off and water shooting up out of the ground? Sprinkler system owners need to correct these problems in order to conserve water.
If automated sprinkler systems are running during the day, they should not be. Watering should be done in the early morning instead of during the heat of the day because water loss to heat evaporation is higher during the heat of the day than in the morning. If you observe your irrigation system when it is cycling, you can tell your neighbors that you are doing your part to manage this precious natural resource. In the green industry, this is called an "irrigation audit."
An irrigation audit involves little more than watching the different stations go through a run time. The object of a sprinkler system is to put on enough water so that the soil is moist down to roughly 6 inches in the root zone. Start the irrigation audit with a visual inspection of the head performance. Look for misaligned irrigation heads — for example, water spraying into the street or driveway (see photo), heads not turning properly, or missing heads. In some instances, heads have been vandalized or accidentally damaged by vehicle tires. These must be repaired before proper pressure can be supplied to other heads.
The next step is to check for correct pressure needed to deliver the amount of water required for proper coverage.
Finally, calculate the amount of water and the uniformity of the system. This is completed by randomly catching the amount of water each station delivers. For instance, in station one of your irrigation system, five small cans placed randomly caught the following amounts water: 0.5, 0.6, 0.4, 0.5 and 0.5 inches. This totals 2.5 inches of water, which divided by the five cans is .5 inch per cycle time. You timed the station one cycle at 30 minutes. So if .5 inch is applied in 30 minutes, it would take an hour to receive an inch of water. The acid test for an irrigation system is identifying how deep the water is soaking into the root zone, so use a shovel to dig into the root zone and check the depth of moisture. If it is two inches, the cycle will need to run an extended time to reach six inches.
The above is a simplified method. An irrigation audit done by a certified irrigation specialist would take into account the soil type, plant selection, amount of shade in the landscape, and potential evapotranspiration (PET) rate to make the correct recommendation.
Let's maintain the proper moisture level in our soils and keep our plant life alive and free from moisture stress. We should make these corrections beforeour precious natural resource is banned from use in our landscape, as it hasbeen in other areas of the country.