1912 siphon touted as engineering marvel, still in use today

The Colorado River Siphon was touted as an engineering marvel 100 years ago. And, indeed, when many engineering “marvels” of that era have been discarded, updated or become obsolete, the siphon is still being used today.

“It's what made possible the irrigation of the Yuma Valley,” according to Carol Brooks, curator for the Arizona Historical Society in Yuma.

Bob Steele, in a history of the siphon for the U.S. Bureau of Reclamation, called it “one of the greatest achievements in engineering.”

Completed in 1912, the tunnel was built under the river to pump water from the All American Canal on the California side to the Arizona side. The water is then distributed to the Yuma Valley through canals.

The reason it was built? To solve a dilemma posed by the building of Laguna Dam, noted Mary Lou Wilkey of the Yuma Historical Society in a 1970 Yuma Sun article.

“Following construction of the dam, the diverted Colorado River could no longer deliver water to the ranchers of the Yuma Valley,” she wrote.

As a consequence, “farmers couldn't get enough water,” Brooks noted.

“To recapture their share of water, it was necessary to siphon the water off and transport it back across the river,” Wilkey wrote.

Engineers from the U.S. Reclamation Service, now the Bureau of Reclamation, determined that the most feasible plan was a subterranean siphon buried under the riverbed just downstream of Indian Hill and Prison Hill.

Today, a 955-foot tunnel of 14-foot conduit delivers the water to the Yuma Valley.

“Down in the canal, in front, is a humongous tunnel that is the siphon,” Brooks explained.

Work on the siphon began in November 1909. It consisted of a vertical concrete shaft on each side of the river, connected by a horizontal tunnel under the river.

“Both Reclamation and Yuma would overcome many trials and natural obstacles encountered in pioneering the construction of such a new engineering concept,” Steele wrote.

Very quickly the site took on the look of a mining camp, complete with a cement house, engine house, office building and three roadways.

“Everyone here (in Yuma) worked on Laguna Dam and the siphon. They needed farmers with mules and horses to do the dredging. Somebody had to dig the canal,” Brooks said.

A man called J.N. Quick and his son used 16 horses to level the hills at the bottom of Indian Hill, according to Steele.

“By the end of the year, 60 men were working 24 hours a day, seven days a week, with no holidays,” he added.

Sinking of the Arizona shaft started on Dec. 27, 1909, and sinking of the California shaft began on Feb. 14, 1910.

“Workers fired up the first big boiler on the ground, and a bull wheel hoisted automatic dump buckets that carried dirt from the mouth of the siphon. While one bucket was hoisted, another was loaded by five Indian shovel men who kept the dirt flying into the second bucket. More shovelers were added as soon as the machinery had been sufficiently tested,” Steele reported.

“Yuma Indians hauled wood from the California side of the river in boats and the Yuma Transfer Company then took it to the siphon site. A 70-horsepower steam engine furnished the power used in construction with wood used as its fuel.”

Steele wrote that by the new year of 1910, the siphon assumed a definite and visible form as workers gradually sunk the Arizona shaft. “At first, there was considerable water in the hole, but workers rigged up a pump that hauled about 300 gallons of water per minute that kept the water out.”

Each eight-hour shift accomplished four feet more of concrete work.

By the end of January, the workers had reached a depth of 60 feet, below level of river. That's when workers encountered “troublesome” pockets of water in quicksand.

Pumps lifted over 600 gallons of water per minute, keeping comfortably ahead of the leaking water. But then drillers hit new water channels and the pumps were unable to lift the water as fast as it seeped into the shaft. So work was temporarily stopped until larger pumps could be installed.

In April, at almost 90 feet deep, the workers struck bedrock in the Arizona shaft.

Undeterred, the Reclamation Service hired deep sea divers.

“They originally had workers doing the diving, but they were getting the bends (decompression sickness),” Brooks said.

So the contractor, Charles W. Corbley, brought in professional divers A.D. Christie and Louis Hammel from San Pedro, Calif.

It was quite a sight. “Most Yuma residents were not used to the odd sight of divers in the middle of the desert,” Steele wrote.

Working in relays, with Christie working in the morning and Hammel in the afternoon, the two divers successfully put six shots of dynamite in the hard pan and gravel below the cutting edge of the big concrete retaining wall.

Asked what it felt like to be so deep in the water by himself, Hammel replied, “Lonesome as hell.”

On June 9, the ground surrounding the Arizona shaft started caving in around the outside of the shaft, due probably to the shifting sand underneath.

Steele reported that Reclamation Service officials decided not to try slipping the concrete casing down the last five feet since the wall was already deeper than needed.

“The officials sealed up the bottom of the shaft with concrete, pumped out the water and quicksand at the bottom of the shaft, and by the end of June the shaft was sealed.

“Derricks and hoists were then rigged up in preparation for the tunneling which would soon start from the Arizona side of the river.”

By the end of 1911, the Reclamation Service had prepared both shafts for the digging the tunnel necessary to connect the two shafts.

By the end of June 1912, the siphon was ready.

On Nov. 18, 1912, the whole town of Yuma, and beyond, celebrated with a special ceremony. Brooks pointed to an old photo of men standing inside the canal waiting for the water to start coming through when suddenly they see a wall of water coming toward them. The cameraman snapped the photo as the men dashed out of the way.

“They weren't expecting a wall. They thought it would come in scattered in all different ways,” she observed.

According to G.S. Scott, author of a 1912 article titled “Opening of the Siphon,” there were 5,000 or 6,000 people living in the area, but “perhaps 10,000” came out to celebrate the opening of the siphon.

Wilkey noted that the completion of the siphon was “an epic event in the history of local irrigation.”

She described the siphon as “a work of scientific and technological genius.”

“Moreover, the disclosure that Yuma's water is piped under the river remains a shocking revelation.”

With the opening of the siphon, a 1912 USBR report notes that water was sold at the rate of $1 per head hour, equivalent to about $1 per acre-foot. On June 29, the siphon was put in operation and the price for water reduced to 50 cents per acre-foot.

Mara Knaub can be reached at mknaub@yumasun.com or 539-6856. Find her on Facebook at Facebook.com/YSMaraKnaub or on Twitter at @YSMaraKnaub.