Low-Volume Irrigation: It can evoke an instant “heck, no” in one irrigation contractor’s mind and to another, it’s just a day’s work.
Is the difference laziness? Or perhaps a lack of ambition? Neither. In fact, in most cases a lack of product knowledge conjures up these feelings.
Education is the key, and manufacturers of low-volume irrigation products have recognized this. They are aggressively addressing this issue by offering free seminars. In addition, they are going even one step further by taking these “hands on” programs to the contractor and the distributor in the field. In-house seminars are going on at the same time for contractors who want to tour the irrigation product manufacturing facilities.
Micro and Drip Irrigation,
Version 2001
“Water is a finite resource with an ever increasing demand, compounded by periods of drought conditions,” says Sam Tobey, president of Salco Products. The need to conserve water in the United States is no longer just a topic of conversation discussed over dinner. It is real, and government and municipal authorities are addressing it. They have not only imposed water use restrictions, landscape restrictions have been imposed as well. These restrictions are affecting the industry. The industry’s answer is to continue to improve the technology of low-volume irrigation, and to offer educational seminars to improve the skills of the installation crews.
Technology has brought low-volume irrigation from the agricultural fields into the mulch beds of commercial and residential landscapes. Low-volume irrigation is the process of providing water directly to the plant’s root zone via slow application. By maintaining an optimum moisture level in the soil at all times, the plant roots are exposed to neither drought nor saturated conditions, significantly improving the plant’s quality. Water is only applied when and where it is needed; there is less runoff, less evaporation from leaves and soil, and the water is not wasted by nourishing weeds between the plants. Low-volume systems can be as much as 95 percent efficient, compared with 60-70 percent efficiency for conventional systems.
“Basically, people grew up with sprinklers, spray heads and hard PVC systems. This is their comfort level,” says Rael Saks, president of Agrifim. “Where low-volume irrigation has been successful has been in places such as Israel, where water shortages mandate strict water usage.”
Drought conditions across the United States are forcing various states to put water restrictions and irrigation and landscaping mandates into place.
Norm Mueller, sales manager for Bowsmith Irrigation, in Arizona, and Bill Hutcheon, sales and marketing manager for Antelco Company, Florida, tell similar tales. Arizona has long-standing water restrictions concerning the use of standard sprinklers, and micro and drip irrigation have become standard installations.Florida has recently put water restrictions in place and in southern Florida, irrigation is restricted. The good news: drip irrigation is exempt from these restrictions. Therefore, a great deal of re-vamping is going on to bring some of the older systems up to the new standards.
Fight or Switch?
Attractive water-conserving landscapes have been created using low-volume irrigation for trees, shrubs, annuals, roses, perennials, groundcovers and herbs. “The response to the use of these techniques by designers, contractors and end-users has been about equally divided between “pro,” “con” and “show me,” says Tobey.
According to Tobey, there are four perspective views in the development of a landscaped area: the designer, the installation contractor, the maintenance contractor, and the owner/developer/government official.
The designer has the mission to develop an attractive and cost-effective landscape and irrigation system. This is all encompassing: acquisition, installation and maintenance.
“Designers who have worked with micro-irrigation systems have developed design details and drawing techniques to the point that they can design a micro-irrigation system as rapidly as they can an overhead sprinkler system,” explains Tobey. “Designers who have not worked on micro-irrigation systems find it difficult to work with such systems because they, in effect, have to start from scratch and develop these details and specifications to communicate their intent to the contractor. However, most manufacturers can provide designers with details and specifications on any of their products.”
The irrigation contractor’s objective is to install a system, carry it to successful operation, leave and have no call-backs. With this objective in mind, some contractors react negatively to the idea of using micro-irrigation techniques, generally because they are not familiar with the products and are hesitant to try anything with which they are not comfortable.
Tobey points out that when the contractors realize that they can use the same PVC materials, standard pipe fittings and solvent welding techniques that they have used for years, their reception to micro irrigation improves. Of course, if polyethylene hose is used, the contractor may be dealing with unfamiliar fittings and attachment techniques. Once the contractor becomes trained and experienced in the installation of low-volume irrigation systems and realizes their simplicity and reliability, they will become proponents rather than opponents.
He went on to explain that in regard to cost, experience has shown that when plant spacing is two feet on center or greater, drip irrigation systems are less expensive than overhead spray systems. Initial acquisition is less costly because the flow rates through the systems are less than with overhead spray systems. Thus smaller pipe sizes, and smaller and fewer valves, pressure regulators, and backflow prevention devices need be used. Installation is less costly because the contractor is dealing with fewer and smaller components. Operational costs are greatly reduced because of the reduced water and chemical consumption associated with a micro-irrigation system.
“A well-designed and installed quality micro-irrigation system requires only a minimum of maintenance,” says Tobey. Check the filters periodically to ensure that they are not clogged with contamination. This is easily accomplished without having to disassemble anything if a pressure gauge is installed just downstream from the filter. When the pressure falls below the level set on the pressure regulator, flush the filter. He explained that this is accomplished without any disassembly if the filter incorporates a flush mechanism, which is standard on most filters.
“Contractors like it once they realize how little labor is involved versus how much labor they perceived it was going to be,” says Kurt Maloney, director of marketing and sales, landscape and turf division of Netafim Irrigation. “The labor component is less when laying and pinning tubing on top of or just beneath mulch; you can install a lot of square feet in a short time.”
The only other maintenance that is required is periodic flushing at the end of the line. Once installation is successful, if the source of the water is clean, flushing may be required only a few times a year.The developer, owner or municipality is interested in a reliable, efficient system that is not conspicuous or attractive to potential vandals. This system must reduce water consumption, be relatively inexpensive to operate, and minimize liability potential. A well-designed, unobtrusive, quality micro and drip irrigation system can satisfy all these requirements. Mueller added that homeowner training is also necessary. Because there are no wet patches, they can not see the system working. They have a tendency to adjust the controller, leading to over-watering, which defeats the purpose of using the low-volume system.
Netafim has a solution for these nervous homeowners. They offer an emitter that is punched into the tubing at the end of the line with a flag that pops up when the system is running.
Dean Dal Ponte, Rain Bird’s marketing manager, landscape drip division, transferred into this division a year ago with the goal of closing the gap between contractors who install low-volume irrigation and those who don’t by removing the unknown. Rain Bird’s Web site has a complete training section that takes the contractor from determining soil type all the way through maintaining a system in six easy to follow steps.
“It’s almost like a natural thing to approach landscape specifiers first, then contractors, about drip irrigation because the United States is going into a drought session,” says Don Dunjean, sales manager for Pepco Irrigation.
“We feel that some contractors are leery of drip irrigation because they dislike anything they don’t understand, for fear it will just cause more problems,” says Maloney.“One of the toughest things a contractor encounters is remembering low-volume irrigation measures in gallons per hour (gph) not gallons per minute (gpm),” says Rick Heenan from DIG Irrigation Products. “I like to remind them that drip is not just for drought times.”
The New Generation Contractor
This is not the end of conventional irrigation, by any means. However, a significant number of irrigation contractors are taking the time to upgrade themselves and their crews into a new generation irrigation company, combining low-volume systems with conventional systems where large turf areas are involved.
Cities, municipalities, water districts and governmental agencies are starting to regulate water use, and the contractor owes it to himself to learn more about what is going on with low-volume irrigation; you don’t want to be left behind.
Solving Known Problems Some industry-wide problems have occurred on many projects at one time or another. Proper installation of the system could avoid some of these problems. Before beginning the installation, there should be no assumption that this system will go in the same way a standard system does.
Clogged drippers. As a rule, using a filter avoids clogging problems; however, if there are clogged drippers, while the water is on, hold a finger over the dripper outlet for a few seconds. The back flushing normally takes care of the clogging. If multiple drippers are clogged, check for a break in the line.
The dripper or micro sprinkler has an uneven flow, or no flow. Possible causes include the line being broken, the filter clogged, the dripper clogged or faulty, or the pressure too high or low. The solutions would be to check the drip line, clean or replace the screen filter, replace or clean the dripper or nozzle of the micro sprinkler, or adjust the pressure regulator.
The dripper or micro sprinkler has an uneven flow or no flow at the end of the drip line. Too many drippers on the drip line cause this. When designing the system, make sure the maximum recommended 200 gph is not exceeded.
The dripper or micro sprinkler keeps popping out of the drip line. Reasons for this may include a defective pressure regulator, drippers or micro sprinklers installed improperly, a faulty or worn punch was used, or the pressure is too high. Replace the pressure regulator, check or repair drippers or micro sprinkler, plug faulty hole with goof glue, replace or clean the punch or replace faulty pressure regulator.
No water flow from drippers or micro sprinklers. As a rule, using a filter avoids clogging problems; however, cleaning the screen in the faucet adapter or opening the filter and cleaning the screen by washing with water should take care of the problem.
The fittings have separated from the poly tube drip line. This is caused by installing the fittings improperly. Placement of tubing was not far enough inside the compression fitting.
Hard water can cause calcium deposits in drippers and micro sprinklers. Remove dripper or micro sprinkler and soak for one hour in a chlorine solution.
Plants appear stressed. Reasons vary; the drippers near the plants may be clogged and need replacing, the line has a break in it and should be repaired, or the run time is inadequate for the plants and needs adjusting.
July 2001