Issue link: https://www.e-digitaleditions.com/i/1349956
WATER USE Wasted Water, Wasted Dollars: How Much Are You Losing? Leaks happen. Whether from components at the pump station or throughout the system to the last lines, irrigation leaks seem to be ever-present in the orchard. They can appear negligible at the source, but when added up the volume of underutilized water – and the energy and cost to move it – can be quite surprising. "On a 20-acre orchard we tested last year, we found water losses of more than 24,000 gallons per irrigation event – just from leaks," said Tom Devol, senior manager of Field Outreach and Education at the Almond Board of California (ABC). "Every grower would like to see that water applied to trees rather than being lost to evaporation or seepage in areas that are out of reach by tree roots. Here at ABC, we're working to quantify these issues for growers." Devol said the key to quantifying water loss – and understanding its effects across an orchard and a grower's bottom line – starts with boots-on-the-ground surveillance and adjustments. While initially this may sound time consuming, the good news is several Resource Conservation Districts (RCDs) across the state offer free irrigation system evaluations through Mobile Irrigation Labs, which identify issues and generate recommendations specific to an individual grower's situation. "You can't manage what you don't measure," Devol said. "That's why ABC has partnered with local RCDs to bring more distribution uniformity tests to growers – free of charge. This is a great starting point for understanding how your water is being applied across your orchard, and in the process it can uncover some issues that may be overlooked because they appear insignificant at first glance." Is your water going where you think it is? Water losses – seen and unseen – can negatively affect your orchard's distribution uniformity (DU), a measurement of how evenly water is applied across an orchard. A high DU rate of 90% in an orchard means that the area receiving the least amount of water gets about 12% less water than the average area of the orchard, while the area receiving the most water gets about 12% more than the average. Contrast that with a low DU rate of 75%, in which the low and high percentages are about 30% – and potentially greater. This drastic variance results in significant under- or overwatering of trees within an orchard. "Better uniformity means more consistent yields and maximized water use and nutrient applications," Devol said. "Not only is this a win for the grower, it's a win for the broader almond industry as it continues to strive to achieve its 2025 Goal of increasing water use efficiency." In 2020, ABC provided a grant to the Tehama County and East Stanislaus RCDs so that both could offer more DU tests through their Mobile Irrigation Lab programs. For the Tehama County RCD, this funding resulted in 30 free irrigation evaluations for almond growers in Tehama, Butte, Glenn, Colusa and Yolo counties. With the program's great success, ABC will be supporting and expanding this service again in 2021. "Understanding how your system is distributing water – whether that's across 10 acres or 100 acres plus – is really important," said Kevin Greer, manager of the Tehama County RCD Mobile Irrigation Lab. "That said, finding balance between the areas closest to the pump, where pressures tend to be the highest, and the areas furthest from the pump, where pressures typically are the lowest, can be difficult." "I tell all my neighbors about it because it's a great service and we need to be cognizant of the finite amount of water we have every time we irrigate." — James Lefor Tehama County RCD Mobile Irrigation Lab Manager Kevin Greer (left) reviews a system map of pressure and flow measurements with Capay grower Chad Johnson. 5