SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/64785
Head-to-head coverage (overlapping the spray from a sprinkler head with the spray from the sprinkler head next to it) maxi- mizes irrigation efficiency. The higher the efficiency, the less time it's required to run the irrigation system to produce the desired results. • Use sprinklers with the same precipita- tion rates within each zone. "Precipitation rate" refers to the amount of water sprays or rotors discharge in inches per hour. Always have sprinklers with the same precipitation rates running together on the same zones for an even application of water over the entire zone. When sprinklers with different precipitation rates are combined on the same zone, some areas of the zone will be overwatered and others will be too dry. • Design using head-to-head coverage. OTHER KEYS TO EFFICIENCY • Regulate water pressure. High water pressure causes water to emit from sprays and rotors as fog or mist, often evaporating or drifting away in the wind and leading to longer run times. Every additional 5 pounds of water pressure (5 psi) over the sprinkler's optimum operating pressure causes each head to use 6-8 percent more water—an amount that can really add up over time. Pressure-regulating valves and swing joints can remedy this situation, as well as sprays and rotors with in-stem pres- sure regulation. • Check nozzle efficiency. Distribution uniformity, or "DU," is the industry meas- urement of nozzle efficiency shown as a percentage or decimal. The higher your system's distribution uniformity, the less time it will have to run to achieve the de- sired results. You can determine your DU by conducting an irrigation audit on your own using a catch-can method, or you can have a third party perform the audit, such as the Center for Irrigation Technology or your sprinkler manufacturer. • Schedule wisely. Evapotranspiration, or "ET," measures the rate that plants lose water through evaporation and transpira- tion. ET is calculated based on tempera- ture, humidity, solar radiation, wind speed and rainfall. ET rates are typically lowest early in the morning, so water ap- plied during that time is less likely to evaporate due to solar radiation. Wind speeds also tend to be lower in the early morning hours than at other times of the day, making it more likely for your irriga- tion water to land where it should and further improving system efficiency. • Consider ET-based control. Using an ET-based control system can reduce irriga- tion frequency by as much as 30-50%. These systems gather local weather data to calculate a daily ET rate. This information then determines whether the system should run on any given day or whether zone/station run times should be adjusted. Even if your current controller is not ET- based, it's a relatively simple upgrade that can save a tremendous amount of water over time. ■ www.stma.org SportsTurf 31