It's no mass government conspiracy that the availability of fresh water is decreasing every day, while populations continue to rise along with the demand for water. It's not as if there are more freshwater sources today than there were a million years ago -there aren't any new ones to tap into. Some scientists predict that by the year 2050, more than one billion people in Asia alone could face massive water shortages. Over the past number of years, this country has experienced many droughts. In fact, if you looked at a weather map of the United States in 2007, it showed 23 states that were either experiencing droughts or on the verge. It's a challenging game we're faced with, trying to curtail our use of water while still enjoying the benefits that it brings. However, it's up to everyone to help do their part, and many organizations are.
The U.S. Environmental Protection Agency (EPA) started its nationwide WaterSense Program 12 in an effort to help educate consumers to choose water-efficient products. Products stamped with WaterSense's approval help users reduce their amount of water usage by as much as 15 percent a day.
To further help the cause, some municipal water districts are offering special rebates which will practically pay for water-efficient products either in new installations or to retrofit an existing irrigation system. Nevada is also offering incentives, allowing builders and contractors who are working on properties that follow Leadership in Energy and Environmental Design (LEED) standards to purchase construction materials taxfree. Other states like Michigan are following similar methods. Meanwhile, some municipalities are fining property owners who fail to adhere to local water limits.
With national, regional and local efforts increasingly focused on conserving, one can't help but ask, "What can the irrigation industry do to help?" "We're seeing an overall trend right now of increased awareness about the need to use products that reduce water waste by increasing irrigation efficiency,” says Mike Baron, director of water management at the Toro Company, Irrigation Division, Riverside, California. “With the cost of water going up and the increased implementation of tiered rate pricing, there’s a greater interest on the part of property owners to make those investments to reduce their water costs.”
This has been a prevailing sentiment for irrigation manufacturers for a number of years. Smart controllers and moisture sensors have become the hot items, allowing property owners to irrigate their landscape only when necessary. But there’s more to water efficiency than merely using moisture sensors and ET controllers and operating the irrigation system less.
If you’re thinking seriously of how you can help your clients cut the amount of water used in their irrigation systems, then you will want to take a step back and really look at how the water is being applied. And where else would you look to get a glimpse of this besides the sprinklers? They are one of the most crucial components in an irrigation system. A poorly set sprinkler, incorrectly nozzled, can tarnish the water distribution for an entire area, wasting countless gallons of water during each irrigation cycle. Thanks to advances in technology in the last several years, sprinklers have become far more water efficient. Companies such as Rain Bird, Hunter, Toro, KRain and others have introduced new and improved sprinkler heads, and innovations continue to be made.
“We’ve had 60 years of history where the efficiency of spray systems has been 50 percent or less efficient because the basic spray technology was limited,” says Jeff Miller, product manager for the Toro Company. “The majority of spray systems in the ground are not very efficient. But that’s all starting to change.”
Let’s talk first about a common misconception which occurs when jurisdictions suddenly impose watering restrictions on its residents. This often happens in the summer during a drought when water supplies are constrained. As a result of the water shortage, homeowners might be required to water their properties only one or two days a week. The idea is that this will help conserve water. What these jurisdictions fail to take into account, though, is how homeowners will water on those days they’re allowed to.
“In areas where they’re dictating when to water, homeowners will set their controllers so they’ll completely douse that area with water,” says Donn Mann, sales manager for Rain Bird, Tucson, Arizona. “That’s not necessarily being water efficient. They’re trying to conserve, and they end up wasting.”
Where most irrigation systems go wrong is a lack of matched precipitation between all of its sprinklers. What we mean by the term “matched precipitation” in the irrigation business is that all of the area being watered by a zone of sprinklers is receiving water at the same rate. This rate is what is referred to as the application rate or precipitation rate. When that rate is equal at every location in the watering zone, then matched precipitation is achieved.
A common mistake installers make is when they install a system comprised of nozzles that don’t work together to deliver a matched precipitation rate. This is especially common when installing rotors that have different arcs. For example, you might find a zone that has one 360-degree rotary sprinkler releasing water at two gallons per minute (gpm), and another 90-degree nozzle that’s also releasing water at eight gpm. Consequently, the area immediately under the 90- degree zone will be over-watered. If, however, the 360-degree was releasing water at eight gpm and the 90-degree was at two gpm, this would create a matched precipitation rate. “
All too frequently, installers don’t change nozzles,” explains Bob Finnegan, chief operating officer at K-Rain, Riviera Beach, Florida. “They will stick with the pre-installed nozzles that came with the rotor. In order to achieve matched precipitation, the nozzle must be changed to the appropriate flow for the pattern being watered. Unless they physically change those nozzles to get a matched precipitation rate, they’re wasting water.”
Rotating stream nozzles
One of the newest innovations to help conserve water is the rotating stream nozzle. Introduced in 2002, the MP Rotator has paved the way with this new technology. Hunter’s MP Rotator line features adjustable arc units as well as unique side strip models, while Rain Bird offers fixed arc models. K-Rain has also recently introduced its rotating stream nozzle which features viscous dampening for speed control. It has a patented adjustable flow control.
Rotating stream nozzles are designed to do exactly what their generic description suggests: irrigate by delivering a multi-trajectory rotating stream. These nozzles are installed on conventional popup spray heads of any pop-up height, which add to their versatility. What makes the various offerings from manufacturers different is whether the rotating nozzles are fixed arc or adjustable arc, and of course distance of throw and arc selection.
Rotating stream nozzles have several advantages over conventional fixed spray nozzles, not the least of which is their ability to water from multiple angles. According to Gene Smith, product marketing manager for Hunter Industries, San Marcos, California, rotating nozzles operate at flow rates that are one-third of the flow rates of standard spray nozzles. “A precipitation rate down that low is much more matched to the absorption rate of the soil,” claims Smith. “The soil can draw in the water as it’s being applied rather than becoming over-saturated and creating water runoff.” Generally speaking, rotating nozzles put the water down more slowly and more evenly and perform better in windy conditions than conventional sprays. What new adjustable arc models are offering is the ability to achieve a matched precipitation rate performance without having to change the nozzles. As you adjust the arc of the Hunter MP Rotator, for example, the flow rate will change automatically. That’s one of the key innovative breakthroughs of this technology. Rain Bird’s matched precipitation rate nozzles can be controlled internally.
“With fixed arc matched precipitation rate nozzles, you pick the distance and the pattern, and the nozzle automatically adjusts so the contractor doesn’t have to do it himself,” says Mann. “It’s matched precipitation rates for dummies. It makes it really simple, and the contractor won’t have to do any calculations.”
On the other hand, Hunter’s MP Rotator lets you adjust the pattern while adjusting the flow rate itself automatically to maintain the precipitation rate. This helps prevent accidental spraying of water onto nearby buildings or hardscapes. “You should be able to use twice as many rotary nozzles on one valve as you can spray nozzles,” says Smith.
“You can use fewer valves, less mainline, a smaller controller and less footage of valve wiring with these products. All those things add up, and you’ll end up saving a lot of money.”
Impact driven rotors have been around since the 1930s, and gear driven rotors were introduced in the 1960s. Over the years, these products have evolved and have been greatly improved. As new technology develops, rotors continue to improve, becoming more efficient and effective. Rotors are ideal for large open spaces where the head spacing is in the 30 to 40 foot range and above. For these larger areas the most efficient and least expensive way to water would be with rotors. Because cost is always a factor, in large turf areas, rotors continue to make an important contribution.
Manufacturers continue to invest money in developing improved nozzles for more uniform coverage and efficiency. One of the newest features on rotors is the shut off feature. Toro’s X-Flow, for example, allows one rotor to be shut off while all the others on the same line are still running. This helps maintenance workers change nozzles more easily to improve efficiency. Rain Bird recently introduced an optional pressure regulating model in its popular 5000 Series which eliminates wasted water from high pressure misting.
Fixed spray nozzles
Spray nozzles have been around for decades. Most sprinklers in the ground today are utilizing conventional spray nozzles. Unlike rotating nozzles, these release water in a fan spray that covers a given arc. In other words, they don’t rotate. To avoid misting, they must run at a relatively lower pressure of 30 psi. Some industry professionals will tell you that spray nozzles are losing the war against rotating nozzles, as the latter offers an array of features that spray nozzles don’t have. Also, normal spray nozzles have trouble watering evenly. “They’re putting water down, but the bulk of it is landing only on one spot,” says Finnegan. “Say you have a spray nozzle with a range of eight feet. Well, most of that water will land eight feet away from the spray head. As you go under that distance, that uniformity gets less and less consistent.”
Others say that there will always be a place for spray nozzles. “Spray heads are quite conducive to tight spaces,” says Smith. Innovations continue to be made in fixed spray technology. For example, Toro has created a whole new category of rotating nozzles with its Precision Series Nozzles. “In the 5' to 15' range, these spray nozzles deliver the water-saving performance of rotating nozzles, but at a much lower cost and without any moving parts,” says Baron. They feature flow rates that are 30 to 40% lower than traditional spray nozzles and are able to save up to a third the amount of water used.
Perhaps what’s most interesting about this product is that despite the fact that their flow rates are lower, they can easily replace existing spray nozzles already in the ground. “You don’t have to change the watering schedules you already have set up,” says Miller. “So from a retrofit standpoint, it’s far easier to change.”
Although rotating nozzles tend to be more expensive than fixed spray nozzles, many irrigation experts say the long-term savings they provide will more than pay off. And because rotary nozzles put water down slower than fixed spray nozzles, you can put more of them on a valve.
As a whole, sprinklers are moving forward at a steady pace. Manufacturers continue to improve their rotary and fixed spray products while at the same time looking into other ways to refine water sustainability. Manufacturers are also working to improve watering uniformity by building sprinklers that release larger droplets of water. “The larger the water droplet, the more likely it is to stay in the area you want it to,” says Smith. “Smaller droplets often get picked up and carried off by the wind. If you send out larger droplets, they have a better chance of performing in the wind and saturating the turf.” Valvette Systems aims to improve over-watering uniformity by allowing installers to adjust each sprinkler independently. Its Little Valve feature (which is literally a small valve located in the stem). Using a key to adjust the Little-Valve, you dial in whatever distance you want the water to be thrown within a four-to-15-foot limit.
This allows for the most precise placement of water possible, eliminating most over-spray. Misting and fogging, a common water-wasting hurdle traditional nozzles face, are significantly reduced at distances over 12 feet and completely eliminated at 11 feet or under regardless of pressure. In addition, the Little Valve can be retrofitted to existing sprinklers. Antelco, a Longwood, Florida-based irrigation company, provides a full line of micro-sprinklers. These sprinklers aren’t very well-suited for turf irrigation, but they’re perfect for watering plants, trees and crops. “They lend themselves perfectly to areas that require a little bit more water than drip,” says Bill Hutcheon, president of Antelco. “We’re putting water only where it counts. It’s like we’re spoon-feeding the plants.”
“There are four key elements to saving water: design, installation, maintenance and management,” says Baron. “Did I design the project properly by picking the proper heads and not putting bubblers with sprays? Am I programming the controller properly? Do we replace broken heads and clean out clogged nozzles?
“It’s never just the equipment. The system will only save water when the regulators and water purveyors understand how the four processes are integrated and interdependent. Until then, those solutions will always be piecemeal.”