Feature Article - February 2006
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Tough Turf

Getting athletic fields in good shape is both complicated and not-so-complicated

By Kyle Ryan


Irrigation

Like pretty much every living thing on earth, grass needs water to survive, and delivering that water is a whole industry unto itself. According to an STMA survey, 80 percent of fields use pop-up sprinklers for irrigation. And like almost everything in this tech-savvy age, sprinkler systems have specific designs for various purposes.

"The equipment you'd use on an athletic field is much different from the equipment you'd use on a golf course or should be using on residential," says Irrigation Consulting's Vinchesi. "Every manufacturer makes a sprinkler that is made specifically for an athletic field."

In spite of that, Vinchesi often sees residential or commercial sprinkler systems (ineffectively) watering athletic fields. Ignorance may explain that, but it probably has more to do with cost. According to Vinchesi, sports sprinklers cost roughly three times as much as their commercial counterparts. The extra cost comes from the extra features: more durability, a stronger retraction spring (to ensure it pops down out of the way when not in use), a heavier case, thick rubber cover to prevent injury and a larger capacity with higher water pressure. Ideally, the sprinklers would deliver roughly 80 gallons of water per minute.

Somewhat surprisingly, irrigation systems don't differ much among the different types of sports fields. The same equipment is generally used on all of them, but the fields all have to be zoned correctly in order for the irrigation to be effective. Even professional fields occasionally have this problem.

"What's happening is some areas of the fields are getting more water than you might like, and some areas of the field are getting less water than you might like," Vinchesi says. "The big thing with sports fields these days, especially on soccer and football, is to be able to deal with the wear areas separately from the rest of the field. So you're overseeding those more, and they need to sort of have their own zoning so you can separate them from the rest of the field when you're doing renovation work."

For example, as few as three rows of sprinklers can irrigate a football or soccer field, but that usually puts a row of sprinklers down the middle, which delivers most water away from the most severe wear areas. According to Vinchesi, this type of design also puts a sprinkler right at the free-kick point for soccer, which can be problematic. A four-row system will move the sprinklers out of the middle, but that system isn't perfect, either.

"It used to be most people, when they did football or soccer, they just zoned right across the field," Vinchesi says. "Well, the wear is in the middle, not on the sides, and if you zone across, you can't treat the sides and the middle separately."

The same setup won't necessarily work for both a soccer and football field, either. Soccer fields get a lot of wear in the goal area, so those parts of the field need special attention. That's one of the main problems Vinchesi encounters on fields: irrigation systems that fail to address wear patterns. It takes Vinchesi about an hour to assess the effectiveness of an irrigation system when he performs irrigation audits. An audit measures how evenly the sprinklers apply water.

"You get a visual result, which is usually very eye-opening because it shows you exactly how much water is hitting in certain areas of the field," Vinchesi says. "You can also collect data and do the math and calculate exactly what's going on and get real hard data. But basically you're seeing how uniformly the sprinklers apply water. You're measuring the distribution uniformity, and you can calculate how your schedule should change because of good or bad uniformity."

Irrigation audits also examine soils and root depth, which can help field managers figure out the best time to schedule irrigation. That, in turn, helps keep managers from over-watering their fields, which is a common problem on lower level playing fields, according to Vinchesi. With water scarcity becoming an issue even in non-arid climates, using too much water can be problematic. Some higher-end irrigation systems have moisture sensors that let managers know how much water a field needs. Although the technology can be high-maintenance, it generally works pretty well and does more than a traditional rain-shutoff system.

In general, Vinchesi recommends that irrigation systems have these characteristics: sprinklers with small surface areas (the smaller the top, the better); sprinklers with a high pop, so they can be set unobtrusively low to the ground; a valving system located away from the field; and a controller that allows field managers to water their fields according to their needs.

"Talk to a lot of people," Vinchesi suggests. "Find out what they like and don't like about their systems, and then take all your likes and have your system done that way. Unfortunately, most [irrigation systems], because some contractor or distributor gave them a standard layout, aren't customized for the field. They tried to do it as inexpensively as possible because it's a competitive situation."

Like a lot of things, doing an irrigation system cheaply and doing it correctly may or may not be mutually exclusive.