July is Smart Irrigation Month! That’s why we’ve connected with Dave Shane, one of Central’s Irrigation Experts, to learn more about smart irrigation, technology, and how efficient products and solutions can help to save water and labor.
The term “smart irrigation” came into common usage about 15 years ago. It generally refers to resource conservation and more recently has evolved to refer to the abilities of the irrigation controller.
Resource conservation awareness in landscape irrigation began about 30 years as the industry grew and became an accepted part of an overarching sustainability/conservation trend. There are several areas where conservation can be applied in landscape irrigation including, manufacturing, transportation, electricity (in the irrigation system), labor (installation, maintenance and management), and water. In this article we are going to focus on labor saving opportunities and water conservation, which is the most obvious resource used in irrigation systems.
Water conservation is accomplished in three ways:
- Delivering proper dynamic pressure to the irrigation devices
- Detecting and stopping leaks and breaks in the piping network
- Replacing just the amount of moisture required to sustain the plant material
Water Savings: Ideal Pressure
Every manufacturer offers performance charts that show the ideal pressure at the spray, rotor, drip tube or other emission device. When pressure is too high or low bad things happen—too much or too little water is used, performance suffers, and the system is inefficient.
Operators often make the problem worse by running the zones longer when attempting to compensate for these inefficiencies. Booster pumps are the remedy for low pressure. Pressure regulators, either at the point of connection, added to the zone valve, or built into the spray or rotor are the remedy for high pressure.
Built-in pressure regulation in spray heads was introduced 30 years ago and is offered by all manufacturers today at 30 and 40 or 45 PSI. Regulation in the spray head ensures large water droplets less affected by wind, resulting in more uniform coverage.
- Ideal fixed spray nozzle performance is at 30 PSI.
- Newer rotating spray nozzles perform best at 40 or 45 PSI, depending on manufacturer.
Pressure regulation at the zone valve was introduced around the same time as built-in regulation for spray heads, although it is not as effective as regulation at the head. Regulation at the zone valve works well in properly designed and balanced systems.
Pressure regulation in rotors was introduced about 15 years ago and is available from most manufacturers in mid-range rotors designed ideally for 30-40′ spacing. Regulation is not yet available in larger landscape rotors designed for 45-70′ spacing but is available in the swing joint that connects the head to the lateral pipe.
Studies show that pressure regulation can save up to 30% of water used in spray and mid-range rotor zones. Clearly, high system pressure is a greater issue than low system pressure.
Water Savings: Leak Detection
The controller is the brain of the residential or smaller commercial irrigation system that determines when each zone run and for how long. Larger commercial customers have had access to computer-controlled systems with on-site weather stations and various sensors for several decades.
Flow sensors constantly compare actual flow to expected flow. Smart controllers use them to identify and quarantine high or low flow zones or even entire mainlines if necessary. Flow is also recorded within the smart controller and can be compared to water meter readings. In some cases, local water purveyors will allow sensors to replace meters.
All manufacturers of smart controllers now offer flow sensing capability although ease of setup and functionality varies. Most can work with multiple sensors flowing into multiple mainlines. More sophisticated controllers offer flow sensors downstream of other sensors. This is ideal for more complex mainline designs, allowing for sections, rather than the entire mainline to be quarantined in case of a break.
Leak detection and reaction conserves water. Exactly how much depends on many factors including: the age of the pipe network, pressure at the source, quality of preventative maintenance and repairs, and even system programming. Some clients report virtually no leaks or breaks while many cite the weekend-long mainline break that wasted tens of thousands of gallons and destroyed the landscaping or sports field.
The reality is that most systems have leaks but the owners and operators are just not aware of them. Properly used flow sensing can easily save 10-15% of all water used.
Water Savings: Controlling Frequency
Once upon a time controller were simple to program and relatively simple in their capabilities. Operators would set programming and perhaps make a few changes throughout the season, as time allowed. Unfortunately, time or other factors did not always allow the luxury of manual programming changes. Runtimes often remained the same throughout the season. Rain sensors were the only available nod to local weather conditions. They stopped or prevented an irrigation cycle depending on a given amount of rainfall.
The first generation of smart controllers relied on an array of several connected sensors to feed weather data to the controller. This collective data would automatically change zone runtimes, attempting to replace moisture lost through evaporation and plant use. It was a huge advancement over the “set it and forget it” mentality operators used with older controllers. Those older controllers, and how they were managed often caused the public, and local or state regulators to view irrigation systems as wasteful.
Huge Advancements: Weather Data
A huge advancement came when manufacturers developed cloud-based software with the ability to integrate online weather data. Controller to cloud communication is through cell modem, Ethernet or Wi-Fi.
Operators who program based on weather conditions rather that “minutes of runtime” report water savings up to 50%. The correct way to think about weather-based programming is that it will always use the correct amount of water—as long as some mental energy is expended to properly complete zone databases of critical information. This information includes:
- precipitation rate
- plant type
- root depth
- distribution uniformity
- crop coefficient and exposure
The more effort put into completing the database, the more scientific the application of water will be.
In my experience, more realistic water savings when programming to weather conditions are around 20%. The actual amount always depends on the knowledge and effort of the system operator. I have even seen a few cases where more water is used when switching from minutes of runtime to weather-based programming.
Soil moisture sensing is an alternative to weather-based programming. Several smart controller manufacturers have offered soil moisture sensing technology with varying degrees of success for many years. Most simply provide a switch closure, much like a rain sensor, to pause or cancel irrigation when a predetermined moisture level is reached. The quantity and location of sensors is critical, as is their accuracy and durability in harsh environments.
Baseline Systems recently became the first manufacturer to earn the EPA WaterSense label in the new category of Soil Moisture-Based Irrigation Controller. They are also the only manufacturer certified by the EPA for both soil moisture sensing and weather-based programming control.
Labor Saving Opportunities
An added benefit of these systems is labor saving through remote management and manual operations. This can now be done anytime, anywhere from a phone or web-enabled tablet. Operators no longer have to be on-site at the controller to make programming changes. It is no longer a two-person task—one at the controller and one in the field—to run through the zones to check heads for proper operation. One person with a phone can now do it all.
Additional savings are in the form of stronger, healthier turf and landscaping, more playable sports fields, more usable open areas and fewer chemical applications.
Don’t Forget the Basics
The ability to manage smart controllers intelligently is a wonderful thing. Unfortunately, in the rush to add smart control, existing field conditions are sometimes overlooked. Smart control is only as good as what is being controlled—the irrigation zones.
The fundamentals of proper design, installation and maintenance still apply. These fundamentals include: zoning based on plant material, hydrozones, and the precipitation rates of the irrigation products. In other words, do not mix landscape beds with turf, do not mix areas in constant sun with areas in constant shade, and do not mix spray heads with rotors.
I’ve looked at hundreds of commercial properties over many years with the goal of recommending the proper central or smart control system. Many times, my recommendations have been to invest the limited dollars available in fixing the field issues first. Controls are not an effective investment when fundamental field problems exist.
Water Savings: Maintenance & Technology
Periodic maintenance is essential to smart control. Stuff happens in the field beyond our control and must be corrected. Spray and rotor seals leak, nozzles get clogged, drip tube gets cut or damaged, heads lose their adjustment and spray into streets, rain sensors get overgrown by trees.
All mechanical products wear out and eventually must be replaced. Systems become less efficient over time if not maintained properly, making smart control less smart.
Smart control of irrigation systems is a good thing and gets better all the time, thanks to advances in technology and product development. The foundation of effective smart control is proper design, installation, maintenance and the selection of the proper control system for the application and customer needs.
Invest a little more on pressure regulation where required, it will more than pay for itself in water savings, healthier plant material and more usable open spaces. Add flow sensing to prevent further waste and don’t forget to factor in maintenance over the lifetime of the system.
As always, rely on Central Turf and Irrigation Supply for assistance with selecting the right mix of smart irrigation products for your project and needs. We’re ready to help you grow!
About Dave Shane
Dave has more than three decades of experience in the irrigation industry in both distribution and manufacturing roles. He specializing in commercial project solutions with an emphasis on controls to meet complex requirements. He is an excellent resource for any technical questions about irrigation systems and finding the right solutions for efficient irrigation systems.