Turf Magazine - March, 2012
Irrigation Audits Pinpoint Problems
Sometimes you have to show a client what a malfunctioning system does to their property
A customer calls and complains that his lawn isn't as green as his neighbor's lawn. It could be one of many things, such as the result of insect damage, turf diseases or soil compaction, but one of the most commonly overlooked causes is an inefficient irrigation system.
When risers wear out or water pressure is too low, it's common for them to not rise as high as they should, delivering water in the turf canopy rather than above it, resulting in poor coverage.
PHOTOS BY JOHN C. FECH.
Making this determination brings good and bad news. The good news is that it provides a genuinely needed and profitable opportunity for you to make improvements in the landscape. The bad news is that it can be difficult to convince the client that repairs are needed. After all, water comes out of the spray heads, doesn't it?
The key to convincing them that their system needs to be improved and updated is to make it visible by performing an irrigation audit. It can be tough to turn a doubter into a real disciple, but once most people see the results of an audit, they understand.
Conducting an irrigation audit is relatively easy to do. It doesn't require any particular skill, just a little care in setting up - and your customer's willingness to see for themselves.
Which came first, the fence or the sprinkler system?
The answer to the question, "Why should I pay for an irrigation audit?" has several legitimate answers. The first is that components break. Irrigation systems require mechanical moving parts. This is easy for customers to relate to, especially if they've had service or repairs to their cars recently. Even if the repair was more of a maintenance item such as an air filter replacement or oil change, all reasonable person understand that mechanical systems require periodic maintenance and repairs.
The second reason for an irrigation audit is more related to basic human nature. When reaping the benefits of automatic irrigation, most people tend to irrigate for the brown spots. They will run a sprinkler system until all turf areas respond by turning from brown to lush green. After all, the customer probably remembers paying $3,000 to have it installed and they want to see it work.
Changes in the hardscape call for changes in the irrigation system.
Never mind that the system is not operating efficiently, which they don't understand, the brown spots will eventually turn green. But, in turning the brown spots green, they are putting way too much water on the other areas of their lawns. This can cause even bigger problems by encouraging the outbreak of turf diseases, not to mention running up large water bills.
As mentioned earlier, irrigation systems are mechanical devices, and as such will fall into disrepair or simply wear out. All parts are subject to the need for repair, but some of the common ones are:
- Tree roots that restrict the supply lines. When visiting recently with a lawn irrigation specialist, he relayed his experience with one of his customers, a heart surgeon. Upon hearing the strange sound of tree roots constricting an in-ground irrigation line, he said, "Oh, we have a boo-ey here." Evidently, that's what heart surgeons call constricted arteries near the heart.
- Heads that don't turn. Heads can become sufficiently worn so that they no longer turn and, consequently, deliver too much water in one part of the pattern and none in the other.
- Heads that turn, but don't follow the pre-set pattern. It's not unusual to discover quarter patterns that turn into 360-degree patterns if they become misaligned. Some need to be realigned; some need to be replaced.
- Leaking heads and pipe connections. When there's a crack or leak in the piping, water seeps into the surrounding soil and causes it to become soggy. That's bad. It can cause root rot.
- Bent risers. If a car, truck or lawn mower runs over an irrigation head at ground level, there's usually no resulting ill effects. However, if the riser is slow to close when it is struck or installed a bit on the high side, the potential for damage is high. Bent risers don't deliver water at the proper angle, resulting in too much on one side and not enough on the other.
- Risers that don't rise above the turf. When risers wear out or water pressure is too low, it's common for them to fail to rise as high as they should rise. When this occurs, they deliver water in the turf canopy rather than above it, resulting in poor coverage.
- Geysers. When the nozzle is missing due to vandalism or age, water is wasted and a lack of adequate coverage results.
- Clogged orifices. Sand and other debris can become deposited in the emitters/orifices, where they significantly distort the spray pattern. These problems become evident during an audit.
- Water pressure that's too high or too low. Use a pitot to check for proper pressure.
OK, now we're ready to discuss how to conduct an audit. Start by locating the turf area that's causing your customer complaints and run each zone that covers it for 10 minutes. In some cases, parts of three or more zones may contribute to the problem area. While each zone is operating, make a quick sketch of the lawn and write in general notes. Typical comments might be "west head not turning properly" or "looks like someone drove over that riser" or "this one is probably leaking". If obvious problems exist, repair them or make the appropriate adjustments.
Next, check the effectiveness of your fixes. Set out collection cans (tuna cans or cat food cans work fine) in the irrigation spray pattern of each head by placing one 2 feet away from a head and another halfway between it and another head. Continue placing the cans until they cover the turf area. After running the irrigation for a period of time, you want to see approximately the same amount of irrigation in each can, assuming the property gets the same amount of sun exposure and other environmental factors. This is called distribution uniformity. You'll never get it perfect, but the closer you can approach it, the fewer problems the lawn will experience as a result of misapplication of irrigation water.
A properly conducted audit should provide information to improve the irrigation efficiency to the property, reduce water costs, lessen pest damage and significantly decrease the likelihood of runoff. These are not small things; the effect of an inefficient system may be a dilution of applied fertilizers and pest control products or movement below the root system, resulting in pest control failure. Clients always like saving money and the opportunity to be a good citizen or steward of the environment can be rewarding.
Repairing and adjusting malfunctioning irrigation components will make a huge improvement in the efficiency of the system and decrease water consumption. But, don't stop there. Schedule a follow-up audit a few months later, or at least the next growing season. Fine-tuning an irrigation system offers additional opportunities for profit and the capacity to produce a healthier landscape.
John Fech is an extension educator specializing in turf and ornamentals at the University of Nebraska. Contact him at email@example.com.