Colin Wills, Arnold Irrigation District manager, checks a sinkhole Monday, May 17, 2021, in the canal in Deschutes River Woods. 

Hundreds of residents in southeast Bend have been without irrigation water since Thursday after a large sinkhole appeared in a canal, causing a measurable loss of water.

The Arnold Irrigation District shut off water to more than 600 patrons Thursday, according to Colin Wills, manager of the district. The canal was losing 30 cubic feet of water per second to the sinkhole, he said.

Sinkholes appear periodically in Central Oregon, where man-made canals crisscross a region of volcanic rock and the occasional lava tube. Wills said his irrigation district can repair most sinkholes when they appear, but last week’s hole is larger than normal and requires additional help.

“We are doing everything we can,” said Wills. “We are hiring a construction company and an engineer right away.”

Kyle Gorman, region manager for the Oregon Water Resources Department, said lava tubes are common in the Deschutes River Woods area, where the sinkhole appeared. But having a sinkhole open up in a canal occurs infrequently, he added.

“Maybe one every few years or so,” he said.

Wills said the sinkhole was drawing in upstream and downstream water. The drop in water volume was noticed around 11 a.m. Thursday.

Rob Rastovich, a cattle rancher and patron of the Arnold Irrigation District, visited the sinkhole and said it was unusually large.

“I’ve never seen one this big. This one you could put a full-size pickup truck in this sinkhole. It’s huge and it goes deep,” said Rastovich. “Fortunately we caught it when we did before it became more of a problem for the irrigation district and those surrounding homes on the canal.”

Rastovich said the district sent him a text message warning about the sinkhole, which gave him time to fill up his pond before the water was shut off completely. He has enough water to last a week.

“As long as it doesn’t go past a week, we should be OK,” said Rastovich. “But it’s a critical time for the pasture, and we are just getting started. If the weather isn’t too hot (it) hopefully won’t get too much damage from it.”

Wills said a number of tests were performed after the water was turned off to locate the sinkhole and check for other holes.

In a statement released late Monday, Arnold Irrigation District said it had hired a geo-physical engineer to explore the conditions of the area and develop recommendations for the repair. Equipment was expected to start arriving in the area Monday evening, with construction set to begin at 7 a.m. Tuesday.

Customers that need water for watering lawns can use potable water, said Wills. Those customers who need the water for agricultural irrigation will need to wait a few more days.

Bob Pohly, a southeast Bend resident, said the water shutdown is challenging the community.

“The water shut off means we might lose some grass and other plants if the water is off too long,” said Pohly. “So far it has been off since Thursday and no end in sight. Most of us are hauling hoses with sprinklers around our properties.”

The shutdown is not the first for patrons who rely on Arnold Irrigation District. Low water supplies last year forced the district to shut off water to patrons in mid-August, the district’s first early shutdown since 1994.

Is there a danger other sinkholes may appear? Wills said that’s hard to say as the sinkholes are a bit like lighting, striking at random.

“It happens to all the districts. We all have sinkholes,” said Wills. “You can never predict when it’s going to happen.”