One of the talking points David Zoldoske, director of the Center for Irrigation Technology at California State University, Fresno (CSU Fresno), took away from a recent smart water innovation conference is that “everything has been done inside: low-flush toilets, low-flow showers….” Potential water savings are now outside, especially in lawn watering and car washing.
The keys to efficient irrigation, Zoldoske says, are to distribute water uniformly and only put on as much as the crop needs.
Poor plant health and death is often caused by over-watering, not under-watering, states Don Clark, principal product manager with Rain Bird.
It’s why EPA is getting involved. The EPA WaterSense program is designed to protect the future of the nation’s water supply by offering simple methods to save water and to protect the environment through reduced energy use. “It has been stated that, in California, up to 20% of all energy is used to move, pump, and treat water,” says Clark. By promoting the value of water efficiency and encouraging innovation in manufacturing, the program helps decrease water use and the subsequent strain on water resources, energy use, and infrastructure.
More emphasis on managing water is critical, insists Craig Pfaff, western region manager with Seametrics, manufacturer of high-value flow meters and controls since 1989. He offers the High Plains Water District in Texas as an example. “The Ogallala Aquifer doesn’t recharge in pace with usage in some areas, so even with best practices, it may be as little as 50 years before inhabitation becomes questionable due to lack of water,” he says.
The shallow aquifer is one of the world’s largest, lying under portions of eight states in the Great Plains–nearly 27% of the irrigated land in the US. It provides 30% of the groundwater used for irrigation and drinking water to 82% of the 2.3 million people in the High Plains. However, since 1950, agricultural irrigation has reduced its volume. Accelerated depletion has emptied some aquifer zones that will take over 100,000 years to replenish through rainfall.
An additional environmental concern resulting from over-irrigation is fertilizer runoff infiltrating the groundwater. “After 40 to 50 years of over-irrigation, we have contaminated the aquifers with nitrates,” states Zoldoske. “They don’t meet drinking water standards, so we must treat them.”
Watching the Skies
To prevent overwatering, ETwater, a Novato, CA-based manufacturer of smart irrigation products, offers the Web-based ETwater Manager that integrates local weather data with cellular smart controllers to create and implement optimal watering schedules. Integrating data from multiple sites for real-time management, it produces water savings of 20-50%.
Because the company’s CEO, Pat McIntyre, believes the future will focus on forecasting and reporting real-time measurements, he is pleased with the addition of 3G wireless capabilities to ETwater’s line of smart irrigation products. The upgrade allows for better coverage through more cell tower access points and faster connections. “The 3G modems provide faster, more reliable connectivity,” he adds.
Rotary nozzles apply water at a lower rate, with no runoff in tight soils.
It not only provides faster connectivity, it also improves the speed of ETwater’s over-the-air programming ability, or OTAP. OTAP enables product software to be upgraded remotely, keeping customers current with new features and functions without the need for new equipment. “Over-the-air updates are embedded automatically, like a computer,” says McIntyre.
No one else in the industry has done this, he says. “The infrastructure is running to keep up.”
But, customers want assurance that it remains contemporary. “Irrigation control should be a 10- to 15-year purchase,” states McIntyre.
The HermitCrab 2, a new smart device from ETwater, is designed for long life. Compatible with 45 different hosts, it has the ability to retrofit existing controllers. The agnostic apparatus can be accessed from any Internet device.
It attaches to the host irrigation controller through a remote digital port—cellular modem or microprocessor—to override the host controller to run weather-based irrigation programs. “It dials in to the Internet two days prior to the scheduled irrigation and adjusts to 24-hour previous weather,” elaborates McIntyre. “The software allows it to capture what happens and make predictive decisions. The forecasting element is where it gets super smart. If the forecast is rain, you select the probability using an algorithm consisting of factors such as soil, sun exposure, slope, plant material, time of year, evaporation rate, and wind.” He claims the predictive aspect can save 20-50% of water usage.
Water savings can also come from alerts of excess flow, which is why HermitCrab 2 incorporates flow management. “People often irrigate when they’re not actively managing it,” elaborates McIntyre. “They may be sleeping or on a trip. If a sprinkler head breaks at five a.m., no one is around. The bill comes 30 to 45 days after use, so it’s hard to track. This monitors flow, shuts down if there’s a lean, and sends an alarm.”
Smart devices like the HermitCrab 2 save more than just water. By eliminating manual calibration, they save time,
ESP-SMTE uses data collected by an onsite weather sensor to determine the evapotranspiration rate
and the amount of usable rainfall.
money and labor. At a cost of $900-$2,500, payback can come in less than one year, McIntyre estimates. “A landscape contractor managing 500 properties can go online and input blocked days or add water windows during periods of water restrictions. Others would have to adjust daily to save what we do.”
He cites Houston as an example. By consulting three years of weather data (weekly rainfall and evapotranspiration totals), the city was able to “bridge” irrigation for 20 weeks one year, suspend the controller, and skip irrigation for nearly half the year. “We’re not trying to conquer nature,” he concludes. “We’re just trying to leverage the weather to make use of what Mother Nature provides for free and optimize water use.”
Digging Deeper
Many products currently available are designed to save water if they’re installed and operated correctly, states Rain Bird’s Clark. For example, smart controllers can save a significant amount of water when compared with a typical time-based controller.
Too often, time-based controllers are still watering when the weather changes because their program hasn’t been adjusted to seasonal changes or more immediate weather conditions. According to Clark, studies show that time-based controllers are typically adjusted by the user one to two times per year. Conversely, smart controllers make regular adjustments to the irrigation schedule automatically to meet the plant’s water needs as weather conditions change.
Some in the industry believe that rain sensors aren’t smart enough. As CSU Fresno’s Zoldoske points out, “Rain sensors terminate when it rains, but what’s in the soil? What does the plant need? A soil sensor tells that. The problem with irrigating by weather is that you assume the system applies a certain amount [of water] at certain times. If the information is wrong, there’s room for error. We’re moving in the right direction with soil monitors.”
Large Landscapes
Large landscapes throughout the US can benefit from a Toro or Irritrol system. Rain Master Control Systems, one of Toro’s brands under Irritrol, offers both software and Internet-based central control solutions. These allow for considerable oversight for any job, no matter what the size.
“Rain Master systems facilitate water savings through flow management, ET Adjustment, and real-time usage data,” says John Crossley, Rain Master Product Marketing Manager. “In drought-sensitive areas of the country, weather-adjusting central control systems are more of a necessity than a luxury nowadays.”
Rain Master Control Systems provide extensive options through their build-to-order facility in Riverside, CA. Customers can choose from different enclosures and communication devices, conventional versus two-wire layout and weather data source. Rain Master’s Internet-based central control program, iCentral, is simple and feature-rich at the same time. In fact, Rain Master is known for having introduced the first Internet-based central control system, says Mike Baron, Water Management Professional with Toro.
Rain Master Controls serve an impressive number of large clients, including Los Angeles International Airport; the City of Newport Beach, CA; Pepperdine University; and both Cal Poly Technical campuses. Not all of their work is in the West, though.
“Missouri Botanical Garden is widely considered one of the top three botanic gardens in the world, and they are using Rain Master with Eagle Plus and iCentral,” says Crossley.
For the large sites such as cities, business parks, and school districts, Toro provides Sentinel, which allows a user to control up to 999 field satellites from a remote location with a desktop or laptop computer. “Sentinel is great for university campuses that want to upgrade existing standalone controls but don’t want to run any new wires,” says Baron. There are satellite controllers that can act as wireless go-betweens to keep information and watering flowing.
When an onsite weather station, Weather Center II, is added in a central location, and connected wirelessly to the sprinklers, watering happens based on evapotranspiration (ET) calculation methods. For some landscapes, this is the right way to go.
Keeping green lawns on the many upscale properties in drought-starved California is no small feat, however. “The bulk of the smart systems use ET. You’re taking the weather data and making estimates,” says Baron. “One thing that makes the Sentinel unique is its integration with moisture sensors. The moisture-sensing technology can take the most advantage of any rainfall that does occur. You’re measuring the presence of moisture in the soil. Rather than adjust the water times on a day-to-day basis, as with ET, we’re waiting until the moisture level reaches a certain threshold. We’re promoting a horticulturally better watering technique by allowing the soil to partially dry out, because applying a little water a day, that promotes shallow root growth.”
There is a lot of specificity possible. Baron says, “Each satellite is capable of running 16 programs,” and each program could have its own designated target. These systems have full mobile compatibility and can send alerts to a smart phone or tablet. They are SWAT [Smart Water Application Technologies] certified and EPA WaterSense approved.”
The offerings of Toro and its associated brands, and their different product names, are somewhat hard to keep up with. “There is a proliferation of products within the industry,” adds Baron. “We’ve become focused on improving irrigation, and we have to stay competitive.”
Incentives
Soil moisture sensors are becoming so important, Zoldoske says that Metropolitan Water, the largest deliverer of water in southern California, launched the first incentive program for them for urban use in October 2013. Metropolitan is offering rebates for water efficient fixtures and equipment. “The industry has matured so that prices are competitive,” he says.
He adds that EPA has recognized the potential water savings and is looking at smart controllers managed by soil sensors. “It’s an important change,” says Zoldoske. “The soil is where you’re trying to put water; it’s where you should measure.”
Because the soil is what’s being measured, an onsite sensor is important. The challenge is to install the sensor at the correct depth, and to make sure that the soil compaction matches where the plant’s root zones are because the sensors can give a false reading in loose soil.
Another obstacle is the fact that it can be cost-prohibitive to put a sensor on every valve, so some put one sensor on the driest zone and use it as a benchmark for scheduling all the zones. However, Rain Bird’s Clark remains confident that as the cost goes down, techniques improve, water prices go up, and education spreads, the industry will see more soil moisture sensors used to save water.
Going With the Flow
The decision of when to water is best accompanied by accurate flow control. “Accuracy is a defining characteristic,” insists Seametrics’ Pfaff. “In many cases, the irrigation market is happy with 5 to 10% measurement accuracy, while the municipal market may want 0.5% or more accuracy in custody transfer of potable water.”
With the cost of treatment chemicals rising, it can have less to do with the cost of delivering drinkable water and more to do with the cost of the chemicals required to produce the water, he adds.
Municipalities typically use one of two types of meters: mechanical, which Pfaff considers inadequate for many municipal applications, and the more accurate electromagnetic—what he sees as the future of metering.
Seametrics recently released a new product for the municipal market: iMAG is a meter targeted at the smaller diameter pipe sizes. “One market we serve is smaller towns,” notes Pfaff, estimating that there are 122,000 cities in the US with 5,000 connections or fewer. “They still need to be compliant with water regulations, but have smaller budgets.”
At a price point under $400,000, the NFS-certified iMAG keeps small municipalities compliant with the 2014 Clean Water Act. In fact, Pfaff says Seametrics redesigned part of the meter in order to meet the standards.
However small a municipality is, Pfaff believes that municipal budgets are bigger than those of farmers now paying for water. Whatever their budgets, he says farmers now want wireless data transmission and more telemetry. “It’s a big change. They have more knowledge about metering and need to know the flow rate so they can set up delivery systems.”
To meet their demands, Seametrics has come up with new boards that can be inserted to adjust to required changes in meters. It’s an expansion capability of the meter similar to that of a computer.
“We can now use an embedded analog output to more accurately drive the metering pump,” says Pfaff.
Ag
Large farms are interested in soil moisture monitoring and wireless Internet-based services, but technology is still limited and that interest is not adequately widespread, speculates Rebecca Shortt, water quantity engineer with the Ministry of Agriculture in Ontario, Canada. Three engineers in the Ministry deal with water issues, focusing on quality, management, and quantity, as they relate to agriculture.
“It can be hard to know if technology helps in a rain-based area,” continues Shortt. “Because it’s rain-fed, it’s not as crucial. It’s going to rain at some point.”
Ontario is similar to the eastern US, she says. “Rain-fed agriculture is the least reliant on irrigation.”
However, because there is increasing demand for consistent quality of high-value crops, and due to unusually dry summers in 2007 and 2012, she says farmers are using irrigation more and that some field crop growers had to purchase irrigation systems.
In general, Shortt believes that growers are already efficient and therefore are reluctant to spend money on smart technology. Water is self-supplied; there is limited communal supply. Therefore, they err on the side of under-irrigating. Of the 3,000 reported irrigators in the province, only 100 have a supply from outside their farm. In a typical year she estimates they use only 2–4 inches of irrigation water.
Nevertheless, they do have increased interest in becoming more precise. Similarly, she says the government has an interest in efficiency. “Farmers are motivated to make the most of irrigated water,” says Shortt. “They want to fine-tune decisions in order to meet their contracts for quality and quantity.”
To do so, some farmers are using moisture monitoring, taking measurements on their own property. “This summer there was renewed interest,” says Shortt. “We did a lot of demonstrations and displays about how to measure moisture: analog, data logger, downloading…. Bigger growers want the convenience of sending data directly to their computer via cell.”
They’re also measuring evapotranspiration to predict plant usage, evaluating temperature, relative humidity, wind speed, and solar radiation for fields of tobacco, potatoes, vegetables and fruit, and nursery crops. Identifying benchmarks is complicated by variable weather conditions and cultural factors such as different varieties of apple trees. “It’s not exactly apples versus apples,” says Shortt. “There are high-density production trees versus traditional, mature established versus new trees.”
Growers are adopting flow meters, especially with drip irrigation. It’s hard to see how much is going out, particularly with the sub-surface drip farmers are adopting for field crops, thanks to 2012’s lack of rainfall. “Flow meters help with leak detection,” says Shortt. “Drip is seen as modern technology, even if it’s not new. The challenge is that it’s not always as water efficient as overhead irrigation, because it can’t take advantage of unpredicted rainfall since the soil must be kept consistently moist.”
Beyond Control
Even with the best controls, if the irrigation system is inefficient, there’s waste. “It’s important to get the sprinkler or drip system to an acceptable level of efficiency,” indicates Clark.
“We’re working on trying to identify high-efficiency sprinklers and sprayers that provide high uniformity,” says Zoldoske, adding that the University is testing products for their pattern of distribution, and overlap of sprinklers, to meet new testing standards that include consistent pressure regulation in the nozzle and the valve in the head, so that when it’s shut off, the system doesn’t drain. “It saves water if every nozzle has the same pressure and there’s no drain down.”
The spray head is the most abused piece of equipment, Clark says. “The water pressure of the nozzle is often too high.”
Basic spray nozzles are designed to provide optimum performance at 30 psi. Often, however, they’re operated at higher pressures, resulting in poor application uniformity. To assure the optimum pressure at the spray nozzle, Rain Bird offers spray head models that incorporate an integral 30-psi pressure regulator in the stem of the sprinkler.
Because distribution uniformity is crucial, Rain Bird is also investing in new ways to broadcast water uniformly and optimize performance across their spray head, rotary nozzle and rotor product line. Their “rain curtain” technology is employed on all Rain Bird rotors. These nozzles provide high distribution uniformity even in windy conditions because they offer excellent close-in watering, and large water droplets to fight wind drift.
While a rotary nozzle applies water at a lower rate, with no runoff in tight soils, Zoldoske says there are companies that specialize in designing systems based on soil type. “We’re seeing mapping of fields prior to designing an irrigation system. Drip irrigation can now be designed in zones so one valve delivers to different soil type areas. Sandy soils have less water-holding capacity, so you have to irrigate more often.”
It’s important to have both flow meters and soil sensors, Zoldoske believes. “It’s not just about how much water is applied; it’s about how well the well is working. You must manage the systems efficiently and know the systems are working efficiently. If the flow goes down, is there a well problem? Meters and sensors tell the changes in conditions–if the system needs maintenance for efficiency.”
Perhaps the biggest challenge facing smart water technology is that water is not expensive enough to justify the investment, according to some in the industry. “When we used to pay for infrastructure, water was cheap; that will change,” predicts Pfaff.
It’s not the only change expected in the industry. Clark envisions a change in landscape plant materials in which there will be less turf and more native shrubs. “Seventy percent of water use at home is outside: watering the lawn and washing the car,” he says. By reducing the size of lawns and introducing native plants, it’s possible to cut down on the amount of watering required.
That can make a difference during a dry year. Because California had a dry spring in 2013, Zoldoske says, there was not enough water deep in the roots. “You need a reservoir for summer. It’s hard to replenish; it can’t reverse quickly. The soil profile should be full going into summer so you’re not playing catch-up.”
As mentioned earlier, an issue with irrigation that is seldom discussed involves runoff. Every time overwatering occurs, fertilizers are washed away. “The regulatory climate around fertilizers in groundwater will soon be scrutinized like never before,” predicts Zoldoske. Using smart water technology to collect data could have the added benefit of protecting consumers. “Good record keeping is an asset to growers. The data can prove your practices don’t contribute to the degradation of the water.”
The data can also illustrate successful programs that benefit plants, the water supply, and the user’s budget.