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Story Last modified at 3:00 p.m. on Wednesday, August 10, 2011

On East Twin Peak...recalling what lies beneath
Mountain Echoes

Frank E. Baker


Brent Voorhees, left, and Frank Baker atop 5,873-foot East Twin peak.
Photo courtesy of brent voorhees

Scrambling up the last 50 feet of a steep gully to the 5,873-foot summit of East Twin Peak this past June with my climbing buddy Brent Voorhees, my brain unexpectedly issued a 'blast from the past' bulletin: we've been looking up for hours, but deep beneath our feet inside the mountain lies a wondrous engineering feat for its day; a 4.5-mile long tunnel with a pipeline carrying water from Eklutna Lake to run the power plant on the other side of the mountain along Knik Arm.

On one of the maps that I'd looked at before the trip, I could actually see a line showing the tunnel's route down through the mountain.

Built by Palmer Constructors and subcontractors from 1951-54, the tunnel was part of a federal government reclamation project to provide reliable power to Alaska's growing population, due mainly to the large-scale military expansion at the beginning of World War II. The Eklutna hydroelectric power project was approved by U.S. Congress in 1950.

During the four-year construction period from 1951-54, Palmer Constructors employed an average of 155 workers with a maximum of 343 during 1953. Wages for the workers ranged from a low of $2.70 per hour for laborers to a high of $3.57 per hour for crane operators. Divers were paid $40.00 per six-hour shift and $20.00 per hour for any time over 6 hours. In addition, they received an additional $1.00 per foot for depths between 60 to 100 feet and $2.00 per foot for depths over 100 feet.

Tunneling began in 1951 from both ends — Eklutna Lake above and along Knik Arm from below. The two headings were connected on Oct. 15, 1953, and according to some sources, were off by less than an inch at the conjunction!

Located 34 miles northeast of Anchorage, the 4.5-mile-long tunnel from Eklutna Lake to the Knik Arm power plant is concrete lined, nine-feet in diameter and has a capacity of 640 cubic feet of water per second (cfs). The system also includes a 1,375-foot-long penstock that conveys water from the surge tank at the end of the tunnel to the power plant turbines.

The intake structure at Eklutna Lake consists of a precast concrete trashrack just over 133-feet long, and 225 feet of precast conduit that's nine-feet in diameter. The trashrack is 60-feet below the surface of the lake at the end of a 500-foot long, 100-foot wide inlet channel.

The dam at Eklutna Lake's outlet, the intake structure and other parts of the system required nearly $3 million in repairs following the 1964 earthquake. Today, the power plant's tailrace along the Old Glenn Highway is a popular fishing spot in the late summer and early fall as salmon return to a nearby hatchery that utilizes water from the project.

Work began in April 1954 to install the two Eklutna turbine units. The project was transferred from the construction phase to operation and maintenance on July 1, 1955. The Eklutna power plant has two, 16,000 k/w generating units each driven by a single, 25,000 horsepower turbine turning at 600 revolutions per minute (rpm). The combined rated capacity of the power plant is about 32,000 k/w. The original power installation included 5 substations and more than 66 miles of transmission lines. The Eklutna Project was dedicated on August 29, 1955. Total cost was about $32 million.

Resting on top of East Twin peak with a sweeping view of Eklutna Lake and the Chugach mountains, I thought about the how tough those tunnel workers must have been back in the early 1950s. I'm sure that some of them, when they had a chance, glanced up toward the mountain we had just climbed, wondering what it would be like to stand on top. But on this warm June afternoon, I couldn't help but think about what it must have been like for them as they ventured farther and farther into the mountain's recesses to where it was cold, dark and damp.

On these trips I always relish the views to far horizons. I've always felt in a strange way that those vistas provide a glimpse into the future. But I believe it's also important to look back to remember the history of a place. After a brief lunch, we put our names in the register, packed up, and began the descent back down the gully to connect with Twin Peaks trail. On this day we'd ventured high. But more than half a century earlier, some intrepid souls embarked on an even more challenging journey deep inside the mountain, far beneath our feet.

Frank E. Baker is a freelance writer who lives in Eagle River.

This article published in The Alaska Star on Wednesday, August 10, 2011.