From gallons per minute to gallons per hour—from visible and unsightly to invisible—
state-of-the-art irrigation has come to the University of Guelph’s Trial Gardens at Landscape Ontario.
I’ve recently completed a practical demonstration of the future of landscape irrigation. With the help of Neil Whitehall from Watertight Home Services irrigation division, John Lamberink of Aquality Irrigation and summer student Tom Seymour, I removed an old irrigation system from the University of Guelph’s trial gardens at the Landscape Ontario site in Milton, Ont., and replaced it with state-of-the-art design, product and installation systems. The project turned into a living classroom over a three-week period, as other members of LO came to learn and contribute to a successful, highly efficient, plant-specific irrigation installation.
After watching us work, Tony DiGiovanni, executive director of LO, observed, “You work your butt off installing state-of-the-art irrigation and then bury your work for no one to see.” Exactly! A professional irrigation system should provide for a healthy looking landscape, while concealing the required irrigation components. Very similar to landscape lighting, where a good lighting designer lives by the motto, “See the effect; not the source.” It should be the same for irrigation designs and installations.
Three types of systems
Three types of systems were installed. Point-source, low-volume irrigation components, provided by Rain Bird and supported by Vanden Bussche Irrigation, now water the perennial plants in the front entrance boulevard. Each of the more than 150 perennial plants has its own emitter buried at 250 mm, making it difficult to see that irrigation has been installed. John Deere and Hunter provided the product for the subsurface annual bed irrigation system. The Hunter drip line is buried 100 mm deep. This provides water to the plants’ roots through capillary action, and is virtually unseen.
A new DC (battery) multi-station controller (no power, no problem) was combined with a rain sensor to prevent watering in the rain, saving at least 12 per cent of the water, plus not drowning the plants by overwatering. Toro, with the assistance of Turf Care, provided an exciting new spray sprinkler nozzle known as the Precision Series H20 chip technology spray nozzle. These nozzles use less water to provide hyper streams of water, that oscillate back and forth inside a specially designed chamber without any moving parts. The results are reduced runoff, lower water use and very uniform coverage. Frans Peters of Humber Nurseries, LO’s past president, noted, “Fantastic coverage,” when I demonstrated the system for him.
So, what’s all the fuss about? Plenty! Future articles will detail each of the three systems individually, with full descriptions and photos, to help you recognize the water-saving plant-specific precision irrigation systems, and incorporate the concepts into your designs. A paradigm shift is occurring when it comes to how we design precision, water-efficient irrigation systems. They are not just thrown in any-which-way, unless you don’t care about the end product you will become associated with.
Old systems be gone
Front boulevard on-surface low volume systems were removed, as they no longer functioned properly, due in part to neglect. Also, the old system did not fit a redesign of the bed by Rodger Tschanz, trial garden manager at the University of Guelph. Four existing Trial Garden annual beds at the Milton site had been irrigated with stationary risers that did not move and were always visible, detracting from the overall presentation of the University’s satellite trial garden project. A micro irrigation system that was watering raised planters around the LO and CNLA offices was replaced by subsurface landscape dripline, combined with ¼-in. dripline, to water hanging baskets.
I considered an industry association to be the ideal place to showcase the best, most water-efficient irrigation systems available, and for that reason I oversaw the irrigation work, ensuring that state-of–the-art systems were designed, utilizing technologically advanced product, and installed correctly. With the new system, most of the irrigation watering devices deliver water subsurface to the root areas of the new plantings — and water or irrigation emission devices cannot be seen. Staff members have been trained on maintenance requirements, plus instructed how to winterize the low volume point source, subsurface and precision spray sprinkler systems without damaging them with the compressed air. These systems now provide a place for members and prospective clients to come and see what is possible with irrigation — given know-how, willingness, money and time.
Point source low-volume perennial irrigation system
Why not leave the old system alone, and add on, it to accommodate the new plantings? Water, and how the plants are watered, is a major issue when it comes to watering landscapes — a luxury to some, an unnecessary luxury to many, and to others a must. The low-volume point source emission system is so precise that only a small quantity of water is now required to help newly planted perennials establish themselves. A group of high school horticulture students toured the site just after this system was installed, and I was asked to explain what had been installed and how it worked. I told the students our low-volume point source system waters about 150 perennial plants for an hour using about the same amount of water they use if they leave the tap running while brushing their teeth.
In reality, if spray sprinklers had been used to create the system in this 60 metre-long (197 feet) bed, it would have required three rows of spray sprinklers spaced at 3.65 metres (12 feet) apart to provide even coverage and close spacing due to the wind that always seems to blow through the site.
While we were installing this system, many green industry vehicles passed by our job site. A vehicle from a well-established irrigation contracting company stopped and the driver asked, “What are you installing?” I explained and his comment was, “It’s a lot easier and faster to install a mist system.” Sprays are sometimes misleadingly referred to as misters, as they can create a water mist if they are operating above the optimum pressure of close to 30 psi pressure or two bar (bar = 14.7 psi). I replied yes, but, is the outcome the same?
Let’s do a comparison to understand why even though the system took about two extra days iof labour, with two people installing, the longterm outcome well outweighs installing a conventional spray system for this sparsely planted perennial plant bed.
Typical spray sprinkler system
200 ft. x 20 ft. with sprinkler spaced approximately 12 ft. apart = 49 sprinklers spaced approximately 80 per cent of radius for closer coverage and higher uniformity 49 ft. x 15 ft. half pattern @ 1.85 gpm @30psi = 90.65 gpm, 90.65 gpm x 10 minutes = 906.5 gallons per cycle.
Hopefully only three cycles per week would be required 3 x 906.5 = 2,719.5 gallons per week (less rainfall due to weather interrupt device – rain sensor).
Watering of non-planted areas encourages weeds and more maintenance which increases labour costs.Overspray onto roadway is an issue with the wind. Not flexible to varied plant water requirements if a variety of plant material is planted that require different amounts of water.
Low volume point source emitter system
Emitters are installed on half-inch distribution tubing installed ten inches below surface with bug cap at surface — keeps full line flow and high pressure in half-inch tubing, rather than quarter-inch tubing which if not done this way when cut, are at full-line pressure and can cause erosion. When installed as shown in the photo on page 26, if the quarter-inch tubing is cut, the tubing continues to work as normal when the station valve opens.
150 plants x 1 gph (gallons per hour) = 150 gph (or 2.5 gpm)
2.5 pm x 10 minutes = 25 gallons per cycle
25 gpc (gallons per cycle) x 3 cycles per week = 75 gallons per week(less rainfall due to weather interrupt device – rain sensor)
No overthrow
Fewer weeds as water is contained right beside the plants and,
75 gallons of water per week compared to 2,719.5 gallons.
Water savings of 2, 644.5 gallons of water per week which when calculated for a 28 week irrigation season = 74,046 gallons not required.
Even though it’s a lot faster and easier to install a mist system, you can never achieve water savings like this. Irrigation professionals need to look at the end result, which should dictate how we approach irrigation. It all begins with the design and the experience of the designer to be able to choose between the many great products that are available, and select the components that will create a highly efficient watering machine.
Watch for the next few articles that will describe in detail the subsurface system by John Deere and Hunter and the Toro precision H2O spray system by Toro’s Kara Gibbons and Turf Care’s Kevin Jensen, both volunteers with LO’s irrigation sector group.
Lorne Haveruk is an Ontario-based water resource consultant, irrigation designer, author, speaker and educator.
