—by Ross Courtney
As growers have transitioned from rill irrigation to microsprinklers and drip tube, even automating when they can to conserve every drop, some irrigation districts in the Northwest, often more than a century old, are still catching up.
“Delivery systems of last century don’t work as well today,” said Justin Harter, manager of the Naches-Selah Irrigation District near Yakima, Washington.
With drought more common — and possibly facing a second straight drought year in 2025 — districts with gravity-fed canals built in the early 1900s in the foothills of the Cascade Range, such as those in the Yakima River Basin, have been making their own upgrades. They line canals with concrete, build reregulation ponds and pipe laterals.
The older districts have more work to do than the three younger Columbia Basin irrigation districts, which first started delivering water in 1948 in the wake of the Grand Coulee Dam construction. Those have pressurized delivery systems supplied by the vast reservoirs along the Columbia River.
Some of the projects are big, costing millions of dollars and requiring the help of federal grants, the future of which are clouded in uncertainty as the Trump administration aims to scale back government spending.
But many upgrades are slow, steady improvements to operational efficiencies that the districts pick away at each year.
“We take a very methodical approach,” said Scott Revell, manager of the Roza Irrigation District, which holds junior water rights in the Yakima Valley and serves a high share of specialty crop growers, including tree fruit. More than half of that acreage is harvested mid-September or later, which means those growers are at higher risk of losing water when supplies decline.
On-farm improvements make the biggest difference, Revell said. Growers have done that, especially with the development of drip tube and microsprinklers.
“That’s huge,” Revell said.
Improvements to sustain irrigation
Naches-Selah has some portions more than 100 years old, but the district has lined canals with concrete and rubber, and piped service, as part of its overall modernization plan. Replacing aging wooden and concrete pipes with longer-lasting PVC pipes is also part of the routine.
From 2007 to 2012, the district fully automated 11 gates, representing about 90 percent of its water service, at a cost of $800,000, paid for by a combination of district funding and grants. Those gates work together remotely to maintain canal and pipe levels to cut down on disruptions, Harter said.
The alternative would have been to build an overflow pipeline, to the tune of $5 million in 2007, and it still would have been less efficient, he said.
Improvements are as old as the district itself. In 1917, several breaks in the main canal caused 30 days of disruptions and $500,000 in apple crop losses, according to an article by a district engineer in an old copy of Engineering News-Record. The district rerouted much of the canal, building 16 new tunnels with coal augers, paid for with a $375,000 bond.
For the Roza Irrigation District, much of its modernization came in the wake of a 1977 drought that severely curtailed water levels. Overall, the district serves roughly 4,000 accounts on 72,000 acres.
“It was really rough,” Revell said. “It took out a lot of farmers.”
Since then, the district has spent $94 million on numerous projects, with the majority, $58 million, paid by district funds.
The district built three reregulation ponds to capture operational runoff that would otherwise end up back in the Yakima River. The district also piped laterals, lined canals with concrete, cut expansion joints to prevent buckling, upgraded user flowmeters and built gravel refits to keep weeds out of pipes.
Since 2014, the district has spent $2.5 million treating concrete cracks with stretch sealant called AquaLastic. When the canals are empty, the material, color-coded by year of installation, looks like strips of tape holding the concrete together.
Next on the big to-do list is piping the last 10 miles of the main canal near Benton City, a project that will require modifying one of the reregulation ponds and will cost $18 million.
“We’re going to need help paying for that,” Revell said.
The district, founded in 1920, eventually wants to pipe 75 more miles of laterals.
The Dalles Irrigation District in Oregon’s Columbia River Gorge is in the process of digitally centralizing information for all district staff and each user to monitor water remotely on an internet dashboard.
The district has connected its pumps, tanks and reservoirs to the network via radio.
The district has roughly 220 user accounts with a total of about 300 turnouts; so far, 80 of those turnouts are connected to the dashboard. Growers must still physically look at the rest of their meters, but the connection is on the way.
The district is young by irrigation district standards. It started in 1961, pumping from the Columbia River to a series of uphill reservoirs. The users, almost all of them cherry growers, receive water from gravity-fed laterals.
Everything has always been piped, said Weslee Cyphers, district manager. No open canals. So, to upgrade, the district must look to “fine-tune” what they already have, such as the meters, Cyphers said.
“We can’t just look at the obvious,” he said. •
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