SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
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Irrigation&Drainage How water pressure can affect irrigation system efficiency and performance Editor's note: This article was written by Lynette Von Minden from Swanson Russell, an agency that represents Rain Bird. budgets and environmental concerns have made it necessary for these professionals to think outside the box to keep fields in attrac- tive, playable condition. When it comes to sports field irrigation, ris- ing water prices and an increased emphasis on water conservation mean that sports turf man- agers must do all they can to use water as effi- ciently as possible. Over the years, irrigation system manufacturers have introduced many new technologies intended to improve water ef- ficiency without sacrificing a field's health and overall appearance. These technologies range from the extremely sophisticated, like central control systems that enable users to schedule and program irrigation for multiple sites re- motely to the seemingly simple, like high-effi- ciency nozzles for rotors and sprays. However, no matter what type of control system or noz- zles an irrigation system uses, it can't operate at top efficiency if the field's water pressure fluctu- I 30 SportsTurf | July 2012 T'S CERTAINLY NO SECRET that sports turf managers and groundskeep- ers are trying to do more with less. From fertilizers and fungicides to equip- ment and pest management, tight ates or is consistently high. That's where the need for pressure regulation comes in. The concept of "pressure regulation" cer- tainly isn't new. Most homes have a few appli- ances or fixtures that regulate water pressure, like low-flow toilets, shower heads and washing machines. But why does water pressure have such an impact on irrigation system efficiency? Water pressure that's higher than the recom- mended level for any rotor or spray will increase its flow rate, forcing more water through the sprinkler than it needs. "Every sprinkler head has an optimum pres- sure operating range," said Chris Dimmick, Rain Bird Corporation's area specifications manager for the Great Lakes region. "During testing, the manufacturer determines this opti- mum range as it relates to nozzle performance. For every additional 5 psi over and above a sprinkler head's recommended operating pres- sure, it will use 6-8% more water than it should. While that amount may not sound like much, it adds up to a very significant amount of money and water when an irrigation system runs multiple times per week, 8 or 9 months out of the year." As if wasting water and money wasn't bad enough, high or fluctuating water pressure also has a negative impact on turf. When water is under excessive pressure, it tends to emerge from the head as mist or fog, which can easily drift away in the wind instead of landing on its intended target. As a result, some areas of the turf may to be too dry, others, too wet. To com- pensate for the dry areas, many turf managers tend to water more often, creating boggy condi- tions in some areas of the field and unnecessar- ily wasting even more water. Not only do they end up with muddy turf and large water bills, the high water pressure and more frequent op- eration cause greater wear and tear on irrigation system components. This situation leads to sys- tems that may break down more frequently, re- quiring a higher level of maintenance and possibly decreasing the system's overall life span. The bottom line? More time and money leak- ing away from already-stretched budgets. For those sports turf managers who aren't sure whether their irrigation systems are suffer- ing from the effects of high or fluctuating water pressure, it's never too late to find out and take steps to alleviate the problem. While it's possi- ble to observe the system in action and see whether water is emitting from sprays and ro- tors as visible droplets (good) or mist/fog (bad), it's better to actually measure the water pressure to know exactly what you're up against. "Mea- suring your water pressure is as simple as at- taching a pressure gauge to a hose bib," Dimmick said. "If you don't have a gauge handy or aren't sure how to measure correctly, an irrigation industry professional in your area should be available to help. It's important to www.sportsturfonline.com