June 25, 2009

93 power poles go up for transmission lines from a new hydro plant near Boise

BY NATE KNIFE - nknife@idahostatesman.com

The poles brought in by a helicopter Monday and Tuesday will help carry electricity from Arrowrock Dam on the Boise River starting next year. The power plant's two 7.5-megawatt generators should crank out enough power for about 15,000 homes.

The $42 million plant 22 miles upstream from Boise is being built by the Boise Project, a group of five irrigation districts, and is financed by bond sales. The Boise Project supplies irrigation water to about 224,000 acres across Southwest Idaho and Oregon. It sells power to lower irrigators' costs.

The Boise Project initially proposed a 60-megawatt hydroelectric power plant in 1989, but the proposal died amid concerns that so large a plant would be too expensive and would hurt salmon.

"This is the end of a 20-year endeavor," said project manager Paul Deveau. "It took a long time to get this put together, but it will definitely be worth it."

Arrowrock Dam, a project of the U.S. Bureau of Reclamation, was finished in 1915.

At 350 feet, it was the tallest concrete dam in the world at the time, according to the Idaho Department of Water Resources.

"They used to brag that it was bigger than the dams on the Nile River," Deveau said.

Water from Arrowrock Reservoir helps irrigate more than 167,000 acres for 46,000 customers, Deveau said.

The dam was built to be retrofitted with a power plant.

The Boise Project operates several hydroelectric power plants along dams, including the 101-megawatt generator at Lucky Peak Reservoir.

The power poles were brought in by helicopter, partly to save money.

"Normally they'd be stood up from the ground," Deveau said. "But since we're putting them up on hills, the cost of dragging them up would have been huge."

Environmental concerns were also considered. Caribou Construction President Breck Glassinger said using the helicopter reduces damage by heavy equipment.

"We are very sensitive to the environmental impacts of any project we work on, and this approach offered the best management practices for placement," Glassinger said.

The power lines will carry electricity to the Northwest power grid.

Forty local construction workers were hired to build the project. Contractors Mountain States Hydro and Riverside Inc. are scheduled to begin testing the dam's systems in December or January, and the plant is expected to go online soon after.

The Arrowrock hydroelectric power plant is the first to be built in Idaho in 17 years. The Milner plant on the Snake River was the last full plant constructed, said Ric Gale, vice president of regulatory affairs at Idaho Power.

Lucky Peak Dam, which was started in 1949 and completed in 1955 by the Army Corps of Engineers, was also fitted with a hydroelectric powerhouse, which was completed in 1988.

Nate Knife: 672-6742