PRB Articles


Reprogramming Irrigation

Photos Courtesy Of R.A. Smith National

Approximately one-third of the world’s 7-billion people live in areas experiencing a water shortage. Equally shocking is that only 1 percent of the world’s limited water supply is potable, or suitable for human consumption. And approximately one-third of that domestic water supply is used for watering landscapes. So how does the worldwide water shortage affect how we as irrigation-design professionals, contractors, and citizens handle irrigation today and into the future?

Despite the seriousness of worldwide water shortages, landscaped green spaces are still held in high regard, and valued by citizens in their communities. Many realize the positive effects of well-maintained green spaces:

  • Increased property values

  • Decreased air pollution

  • Controlled soil erosion

  • Beneficial water quality.

An increasing number of communities are assuming a proactive stance to conserve and preserve water resources. In some communities, the efficient use of water is not only a “good idea” but rather a mandated requirement. Many areas experiencing a water shortage are in the initial stages of imposing landscape watering restrictions, which may require upgrades to water services and facilities. These upgrades are vital to the conservation of water supplies. The initial expense can be substantial, depending on the scope of the changes, but the long‑term benefits make it cost-effective for everyone.

The Time Is Now

Carefully designed landscapes are still worth creating and maintaining. So, how to keep them growing and lush? Based on existing and looming water shortages, it makes sense to consider alternatives to the use of potable water for landscapes. Non-potable water has become widely recognized as an alternative resource and an acceptable, and even popular, means of sustaining landscapes and water resources. Non-potable water can be collected from the water expelled from air-conditioning units, rainwater, storm-water runoff and, in some communities, treated commercial and residential wastewater.

The use of non-potable water for irrigation has had a slow start, but the practice is gaining momentum. Organizations such as the United States Green Building Council encourage the use of non-potable water collection and use as part of its Leadership in Energy and Environmental Design (LEED) certification process. A property owner can receive six to 10 LEED-certification points by using reclaimed water and water-efficient irrigation systems. In the future, the water-conservation methods that are eligible today for LEED-certification credits will likely be required as part of a municipality’s ordinances and codes.

A time is coming--sooner rather than later--when landscape architects, irrigation specifiers, and contractors will be designing with, and using, non-potable water to create efficient irrigation systems. Even those at the forefront of designing these systems will need to become reacquainted with new technologies and local regulatory codes.

Equipment And Technology

Designers and contractors will also need to become educated in advancements made in the durability of irrigation equipment, the efficiency of all irrigation components, and the effectiveness of various types of equipment in preserving water resources.  Importantly, designers must be able to understand how non-potable water may affect the components of an irrigation system, as well as the plants and turf being watered.

The irrigation industry is responding by designing and developing more efficient irrigation equipment, along with new technologies in rainwater-collection systems.  New products that tolerate higher

concentrations of potentially corrosive chemicals, grit, and debris suspended in the non-potable water are being developed. Improvements have been made to the filtering systems, baffles, screening applications, pumping systems, and controls.

Several irrigation products currently on the market with more to come may affect the efficiency of the irrigation design. The following products are several examples of new technologies.

  • New pressure-regulating devices help maintain consistent water pressure. For every 5 pounds per square inch in reduced water pressure, water consumption is reduced by 6 to 8 percent.

  • High-efficiency nozzles provide a more uniform distribution of water, and can help eliminate overspray. Check-valves prevent water from draining out of the low sprinkler heads.

  • Drip tubing, drip emitters, and direct root-watering equipment apply water slowly and directly to the root systems of plants, again using less water than a conventional sprinkler irrigation system.

  • Smart irrigation controllers use soil-moisture sensors, rain sensors, and ET-based technology to adjust schedules based on the specific site requirements and variable site conditions.

Irrigation For The Location

Even with all of the new irrigation technologies in place, water savings cannot be maintained without proper design, installation, and ongoing maintenance. With yesterday’s irrigation controllers, the time, day, and run cycles were set, and they ran as scheduled until someone decided to make a change, or at best, the rain sensor interrupted the schedule during a rain event. The controller did this regardless of each zone’s precipitation rate, sun exposure, temperature, humidity, wind, soil type, and slope or plant type. Today’s Smart Controllers use site-specific conditions and local weather data to maintain and adjust the schedule for more effective use of water. Applying the correct amount of water in the correct place at the correct time will conserve water, save the owner money on the water bill, and ensure that plant material will be healthier in the long run.

As professionals in the landscape and irrigation industry, we need to be aware of current and pending water shortages, and the continuing evolution of improving solutions. We must progressively react to these water issues, to continue to work diligently in preserving this precious resource, and to educate the public to use smart water practices.

Chuck Stassi is a landscape and irrigation designer with R.A. Smith National, Inc., civil engineers and surveyors in Brookfield, Wis. Chuck has 39 years of experience as a landscape architect and 25 years experience as a landscape-irrigation designer. He has provided landscape architectural and irrigation design for numerous commercial/retail, industrial, athletic, and residential projects. He can be reached at chuck.stassi@rasmithnational.com .

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