NAMPA, Idaho — Gains in irrigation efficiency will benefit farmers, ranchers and entire watersheds this year even if a hoped-for snowpack rally does not materialize, experts at the Idaho Irrigation Equipment Association’s annual industry conference said Jan. 10.
Even relatively minor fixes can produce major benefits to irrigators, said Waive Stager, who owns Sprinkler Head Rebuilders in Buhl.
A worn nozzle changes how much water is delivered and can hinder flow mechanics.
“Sometimes the nozzle will wear unevenly so you don’t have the stream properly directed to operate the sprinkler,” Stager said.
She advises irrigators to check for wear from sand or silt in water, which can make nozzle openings too big or even misshapen so they deliver more water than is ideal for the irrigation system and crops.
Worn washers are another problem, causing leaks and even resulting in water failing to reach the crop, Stager said.
Replacement parts can operate at peak efficiency for several years depending on how much they are used, and on water quality, she said.
Gains in irrigation efficiency help maintain the water supply while benefiting individual users, said Dan Axness, who coordinates Idaho Power Co.’s irrigation segment.
“If you are inefficient, then you are expending your money and effort for no benefit,” he said.
How much is saved by ensuring top efficiency varies based on individual systems, as well as water quality and even the amount of wind, which can impact coverage uniformity, Axness said.
Lee McConnel, who farms in the Payette River Basin above Black Canyon Reservoir, said he and his brother reduced their water usage by half after converting from gravity-flow irrigation to sprinklers. They moved to wheel lines, and then pivots.
Farmers are more conservative in drier years, sometimes even changing acres planted and crops grown, said Ron Abramovich, USDA Natural Resources Conservation Service water supply specialist. Efficiency can increase in ample- and high-water years because systems stay primed throughout the season.
Jan. 8 snowpack was about 70 percent of average in the Boise Basin — where irrigators from now on need about 64 percent of average runoff for adequate irrigation supply, he said. It's 74 percent in Payette, 98 percent in north central Idaho’s Clearwater and 98 and 107 percent in Bruneau and Owyhee, respectively, near the state’s southwest corner.
Irrigation efficiency gains and conservation are among reasons the Bear Lake system in southeast Idaho and northeast Utah does not need major snowpack every year, Abramovich said. When it fills, it can supply irrigators for more than three seasons.
The Salmon Falls basin in south-central Idaho puts a higher percentage of its water onto crops than it did in the 1990s thanks to lining canals and taking other water-saving steps, he said. These improvements extended the growing season by a week to 10 days.