New program helps turfgrass managers with watering times and amounts

In California you don’t have to have your own weather station to access accurate and efficient irrigation scheduling. It is all available online, including networking with dozens of weather stations across the state, and water conservation can be achieved through any computer with access to the Internet.

Although most turfgrass managers will have to reset their controllers manually, at least irrigation can be accurate through the online Wateright program.
Photo by Don Dale.

The free service is called Wateright, a program set up by the Center for Irrigation Technology, a nonprofit on the campus of California State University at Fresno. Project Manager Kaomine Vang says the program started up in 2001 with the first draft of the website, It was funded by the U.S. Bureau of Reclamation.

Wateright is basically an irrigation scheduling system where site-specific calculations can be made online, based on the latest weather data from a state-sponsored weather station near you. Three separate programs accommodate commercial turfgrass managers, farmers and homeowners watering their lawns and landscapes. Local weather stations allow calculations based on common factors such as evapotranspiration rate of turfgrass, temperature, wind, solar radiation and the crop coefficient of grass.

The program is set up to utilize data from 120 weather stations in the California Irrigation Management Information System (CIMIS) or AgriMet, an agriculture-based set of weather stations. The CIMIS stations, being more often based in and around cities, are the ones used by Wateright, though some of the 60 AgriMet stations in Oregon, Washington, Idaho and Montana can be used by turfgrass growers in those states by plugging into Wateright through the website and selecting the AgriMet choice on the scheduling page. Users of either the CIMIS or AgriMet systems can find the weather station nearest them from a map provided on the website and enter it into the scheduling program, giving them an accurate and continual picture of their local weather conditions.

Going to the website, managers will find a scheduling template which, once they fill in their turf site’s specific information, will give them exact watering times and amounts for the week. Up to six irrigation stations at the turf site can be accommodated. If more stations are needed, another schedule must be filled out. The website utilizes cookies that allow quick access when you return to the page later. There is a choice between nine different warm-season and cool-season grasses, from bentgrass to zoysia, which means managers in any area of the state can utilize the program for their grass species. There is some preparation work that must be done in order for the final irrigation to be efficient, however.

“We put everything in there so that as a turf manager all you have to do is set out six catch cans,” Vang says. Sprinkler catch cans must be set out on the lawn during watering to determine precisely how much water each irrigation system is putting out, and there are instructions on how to use catch cans on the website. The cans may be set out in a variety of patterns on the grass to help you obtain an accurate measurement of your sprinkler’s output, and Vang says the driest area of the turfgrass facility is usually measured so that scheduling allows adequate water to all areas.

The irrigation application rate is generally listed on commercial sprinkler heads or in company literature, but the catch cans give exact outputs in inches per hour for each individual irrigation system that will be plugged into the scheduling program. Once the information is entered, the program will calculate and tell you how long to irrigate each station whether it’s watered two, three or four times per week.

The most difficult part of the scheduling is setting out catch cans to measure precisely how much water individual sprinkler systems put out.

The scheduling coefficient sounds like a complicated figure, but Vang says it is generated automatically on the website based on the turf type. This can be tested on the website by going to the commercial turf scheduling page and progressing through the data it requests. You will need to provide details about your catch can test, such as its duration and the number of cans used. After you provide information on the spacing of sprinklers, the scheduling coefficient will appear automatically on the scheduling page.

Irrigation can be set to begin on any desired day of the week, and scheduling can be set for one, two or four-week intervals. Professional automated irrigation controller systems can be set to utilize the weather station data automatically, but most managers will have to manually change their controller settings as the seasons progress and weather changes. There is even a way to calculate drip irrigation scheduling for farmers.

Vang also points out that the Wateright website takes in data from weather stations from the previous 24-hour period, so there is a delay in the relay of weather conditions that must be taken into account. For example, if a lawn or turfgrass facility uses data from the previous sunny day, and it is cloudy on the day of irrigation, the manager should use his own judgment on whether to decrease the irrigation that day. There is a component of the scheduling calculation whereby a user can figure in a percentage of application based on his judgment of how much less irrigation might be used under a low-sunlight condition, which of course involves some guesswork.

This last “adjustment” part of the irrigation scheduling calculation can also be used to account for other variations in the turfgrass to be irrigated. For example, there may be different microclimates within one irrigation station, or part of the station may be largely shaded by trees or buildings for much of the day. Percentage adjustments, based on the manager’s educated guesswork, can make those irrigations more efficient and avoid costly waste.

With 120 weather stations providing data throughout California, the Wateright irrigation scheduling system can be very accurate.
Photos by Kaomine Vang.

The website offers tutorials on how to set up a schedule using the above elements, and also hosts a number of articles on subjects such as distribution uniformity and scheduling irrigation either on water budgets or sensor data that can be good background material for turfgrass managers. There’s even an advisory that kids can use for the irrigation scheduling of their home lawns, thus educating them in the wise use of water.

Vang says the Wateright system has been used successfully by managers of commercial properties, home lawns, schools, golf courses and sports facilities over the years. It was originally designed for golf courses, which is one of California’s big water users, but he sees even more potential in the future for the smaller facilities and residences. Using educated guesses or even soil probes to test moisture may not be as effective when determining the needs of various grasses. The potential savings are significant, with some early tests showing savings of up to 25 percent of a facility’s water usage.

“I’m pretty sure it could be higher than that,” he says, noting that some sprinkler systems he sees are sending water running down the streets. The Center for Irrigation Technology would like to conduct surveys and research in the future to determine exactly how many turfgrass managers are using the Wateright program and how it could be more effective. That would be a worthwhile project, since water is becoming more and more scarce in the arid West.

Don Dale resides in Altadena, Calif., and is a frequent contributor to Turf. He has covered the green industry for more than 10 years.