A Tool for the Future

By Janet Reilly, Rain Bird Corp.

Polyethylene tubing allows the contractor a customized layout that can more easily conform to the needs of specific areas and plantings. The maximum flow recommended through 1/2" drip tubing is 240 gph or 4 gpm. The maximum length of 1/2" drip tubing that can be run directly from the water supply to and through the watering area is 250 feet.

Go across the country and ask a dozen landscape irrigation professionals about drip irrigation. You may get a dozen different opinions, but one thing is certain, you?EUR??,,????'???ll find more interest than ever. And for good reason. As the concern for intelligent use of water becomes more evident, more contractors are taking the time to investigate how drip can play a bigger role in their business.

Although spray head and rotor-based irrigation systems are being engineered to be more and more precise, no single irrigation management approach provides the water-saving capability of drip. Repeated comparisons show that it outperforms traditional systems by 30 to 65 percent.

 

Landscape dripline grid

These savings are possible because, unlike other methods, drip represents the most specific tool available for any nonturf area large or small. This includes shrub beds, flower gardens, areas with mixed plantings and areas sensitive to overspray due to wind and/or high traffic. It can be targeted to deliver water slowly, at low pressure and at or near the root zone of a plant. It operates at low pressures (typically 15-50 psi) and uses flow rates, which are measured in gallons per hour (gph) instead of gallons per minute (gpm).

In addition, contractors find that drip systems can be easily fine-tuned to deliver water in the most ?EUR??,,????'??user-friendly?EUR??,,????'?? way for specific plantings. Emitters, bubblers and microsprays can be selected to distribute water to the foliage itself or only to the soil. Due to the low pressures involved, there is negligible evaporation loss, and there are no problems with overspray that waste water and cause public concern.

Photo courtesy of Rainbird

The bottom line, then, is that it?EUR??,,????'???s possible to achieve significantly higher efficiency with drip – 90 to 95 percent as compared with 30 to 60 percent with sprays and rotors.

To operate effectively, a drip system requires regulators to ensure water entering the system does not exceed maximum operating pressures (15-50 psi). In addition, water entering the system needs to be filtered to prevent large particles from clogging downstream components and ensure that smaller particles won?EUR??,,????'???t impede flow from the emission device. Filter selection is important to minimize maintenance, and self-cleaning filters are available, which can virtually eliminate maintenance in some applications.

Photo courtesy of Rainbird

To aid in efficient installation, manufacturers now package kits that include all of the components (valve, filter and pressure regulator) needed for a specific control zone. A recent advance, which is now available in these kits, is a new low-flow valve developed by Rain Bird for landscape drip applications. It is designed to work in low-volume systems without filtration due to its patent-pending double-knife diaphragm. The new low-flow valve can handle flow rates down to 0.2 gpm, while allowing it to seal watertight despite particles that clog other designs. This new design not only saves water by preventing weeping, it also helps reduce installation time.

For dense plantings, inline emitter tubing is usually used due to its ease of installation. However, polyethylene tubing with pop-up micro-sprays or PVC pipe with polyflex risers and bubblers can also be used. For sparse plantings, polyethylene tubing with emitters or PVC pipe with polyflex risers and emitters are recommended to better water individual plants and reduce the watering of the soil between plants.

Self-cleaning filters (here, the Automatic Filter Kit with glass-filled nylon and stainless steel components) virtually eliminate maintenance in some applications.

Choosing the appropriate emission device is often the most confusing choice in drip irrigation. Emitters come in many different flow rates and styles. Some emission devices are designed specifically for dense plantings and are considered broadcast emission devices. These include in-line emitter tubing, microsprays, misters and pop-up low-volume sprays. Annual flower beds are one example of where pop-up sprays with low-flow nozzles would be beneficial.

Installing a system tailored to meet individual plant needs involves multiple connections. However, Rain Bird?EUR??,,????'???s recently-introduced Easy Fit Compression System has made this significantly easier and more time efficient. It enables a versatile selection of nine different couplings, elbows, tees, adapters and a flush cap to produce over 160 different configurations and accommodate virtually any connection situation. This adds efficiency because it simplifies both stocking and installation. Equally important, the compression fittings allow connections to be made with 50 percent less force and are compatible with any manufacturer?EUR??,,????'???s 1/2" o.d. tubing.

This tool, made from lightweight nylon, allows quick and easy installation of emitters and modules into poly drip tubing.

Developments like these will be of continuing importance in moving drip irrigation to a top-of-mind position in landscape maintenance. No other method combines its ability to demonstrate responsible conservation while doing a better job of meeting landscape water requirements. Equally important, contractors who perceive drip irrigation as a proactive tool for their business plan will be gaining an important edge for the future.