Choosing components for efficiency
1 Mar, 2008 By: Heather Kraus Landscape ManagementWhen installing a new irrigation system or upgrading an existing system, it's important to consider the many system components available that can increase efficiency while maintaining healthy plant life.
Irrigation manufacturers are making increasingly efficient products that pay off monetarily — considering the long-term cost of water — and in the continued beauty and health of plant life.
Nowhere is the efficiency of an irrigation system more visually apparent than the results of proper watering on turfgrass. Generally speaking, efficient irrigation results in turf with a uniformly green color and consistent texture. With too little water, the grass gets patchy and brown; water too much and you end up with soggy areas that increase the potential for harmful fungi. When an irrigation system is not designed or installed with emitting devices that cover the area with a uniform application of water, it is even possible to have both results at the same time. The products you choose will have a tremendous impact on your system's water usage and overall performance.
 New irrigation products save money and help maintain the beauty and health of plant life. |
Spray head nozzles and rotors
Spray head nozzles and rotors designed for efficiency can often compensate for poor system design or installation. For example, a system may be designed at 30-ft. head-to-head rotor spacing. However, the as-built installation may have some rotors spaced at 28 feet and others at 32 feet. Nozzles designed to be efficient and uniform can compensate for this lack of installation precision.
In spray heads, fixed-arc-matched-precipitation-rate (MPR) nozzles are more efficient than variable-arc nozzles. Some manufacturers even offer a next-generation series of highly efficient spray head nozzles that can reduce water consumption by up to 30% when compared to conventional spray head nozzles.
For rotors, nozzles designed to distribute water evenly over the length of throw and gently apply water close to the head are important considerations when choosing an efficient rotor line. Another equally important factor is nozzle selection that approximates matched precipitation rates. Matched precipitation can be achieved in several ways. The first and most effective way to match precipitation is to zone/valve your quarter, half and full-head patterns separately.
 Today's spray head nozzles can reduce water consumption by up to 30% compared to older style spray nozzles. |
If your heads are spaced evenly, choose the nozzle that performs for the given distance of throw. Run half patterns twice as long as your quarter patterns and full patterns four times as long as the quarter patterns. In this instance, you would run your quarter zones for 10 minutes, your half pattern zones for 20 minutes and your full pattern zones for 40 minutes. If you were to run all your rotors for the same amount of time, you would apply four times the water on your quarter-pattern turf area than your full-pattern turf – wasting water and creating overly irrigated zones.
If you do not have the benefit of separately zoned rotors, nozzle selection is your next best solution. Manufacturers provide performance charts that are readily available through their catalogs, distributors or online. While you won't be able to achieve true matched precipitation when using different nozzle sizes, you can approximate it by choosing a nozzle for a quarter pattern that has half the flow of the half pattern it is zoned with.
Some manufacturers sell matched precipitation rate nozzles for rotors that are easy to use across several radius and arc patterns. MPR nozzles offer particularly high levels of water efficiency by allowing sprinklers with various arcs and radii to be mixed on the same zone. Various types of MPR nozzles are available for even water distribution and design flexibility at various rotor radii.
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