Wear and tear threaten critical Malheur County siphon

Owyhee Irrigation officials are looking to make repairs to sections of the Malheur Siphon during the next year because wear and tear has taken a toll on the structure.
(The Enterprise/Pat Caldwell)

By Pat Caldwell

The Enterprise

NYSSA – Almost from the beginning there were signs one of the region’s most iconic symbols was in trouble and now the Malheur Siphon needs up to $2 million in repairs.

Time and soil elements induced damage to specific sections of the 4.3-mile irrigation lifeline.

“We are fighting Mother Nature and what the soils are doing,” said Jay Chamberlin, manager of the Owyhee Irrigation District.

The siphon was finished in 1935 as part of the ambitious Owyhee Dam project. The familiar tube furnishes 300 cubic feet of water per second to agriculturists of the Owyhee Irrigation District in the northern section of the county. That translates into about 2,244 gallons of water per second – a rate that would fill a standard swimming pool in about seven seconds.

The siphon begins in the southern part of the valley and ends north of the Malheur Butte. The water in the siphon comes from the Owyhee Dam. The siphon moves water to fuel numerous irrigation canals and laterals in the northern part of the county.

Chamberlin said the structure’s legs are the issue. The soil where the legs are lodged – specifically near Malheur Butte and Foothill Drive – consists of bentonite clay. The soil swells and compresses each day as the temperature climbs or falls. That motion forces the support legs to move, sometimes as much as several inches a day, which in turn stresses the big water, tube.

“That causes the pipe to be misaligned and, literally, it has kinked itself,” Chamberlin said.

If the problem isn’t fixed, the pipe could fail and deprive farmers of needed water. The economic impact would be devastating, Chamberlin said.

“Just in crop loss it would be $18 million,” Chamberlin said.

Yet the problem isn’t a new one. Officials knew the siphon faced challenges with soil movement just a short time after it was finished.

A mid-1940s narrative from the Society of Economic Geologists reported that within three years of its construction the supports of the pipe showed “severe distress in the section lying north of the Malheur River.”

Chamberlin said officials tried several methods over the decades to resolve the problem, including retrofitting and welding to realign the support legs.

“We added onto the legs, put cables on the legs all to try to force them into position,” he said.

While the stopgap measures worked for a long time, now the situation is becoming acute, he said. The irrigation district hired an engineering firm to evaluate the siphon. The district also is asking its nearly 1,500 patrons to pay a special $1.50 assessment per irrigable acre to raise about $100,000 towards the repair work.

“It is just a fund to keep the project moving forward,” Chamberlin said.

That includes paying for additional engineering evaluations.

The repair will mean drilling deep into the ground to build new support legs, Chamberlin said.

The new assessment won’t enough to repair the siphon and the irrigation district is hunting other sources of money.

“We just don’t have that kind of reserve money available to us and we are looking at grant and loan opportunities. We are looking at the scope of the work to figure out if there is some of that work the district can do itself and subcontract other portions of it,” he said.

While the U.S. Bureau of Reclamation manages the siphon and retains jurisdiction over the structure, the maintenance the aqueduct rests with the irrigation district.

“We transfer operation and maintenance to the irrigation district,” said Brian Sauer, water operations manager for the Bureau of Reclamations Middle Snake River field office.

There is some mystery about when, or even if, the condition of the soil was known when the pipe project was built.

“We are trying to determine if the industry knew that there was a thing called expansive soils, and, if so what harm getting that soil wet might do to a facility such as the siphon. Was it common knowledge and therefore did BOR know?” said Vicki Hoffman, BOR water operations manager.

Chamberlin said what was known about the engineering challenges is a key question.

“If it (the siphon) was part of the original project, which it was, and it was giving them trouble way back then, then why was it not addressed back in the 1930s and 1940s?” he said.

Chamberlin said the siphon is, overall, still a sturdy structure.

“For as old as it is, it is worth saving,” he said.