Irrigating Idaho’s Breadbasket

Posted: May 1, 2023 at 4:20 pm

Devoted team keeps electricity, water flowing behind the scenes at pioneering Minidoka Dam

During tours, the cavernous Allen E. Inman Powerplant at the historic Minidoka Dam impresses visitors with its magnitude and powerful generators. The force of the Snake River spins turbine blades to power generators and produce electricity.
During tours, the cavernous Allen E. Inman Powerplant at the historic Minidoka Dam impresses visitors with its magnitude and powerful generators. The force of the Snake River spins turbine blades to power generators and produce electricity.

Story and photos by Dianna Troyer

Little did engineers and laborers more than a century ago know the small Minidoka Dam and power plant they built across the Snake River would eventually irrigate a colossal number of crops.

Although dwarfed in size and not a household name compared with Hoover Dam, the Minidoka Dam has a mighty impact and is a major reason households have food. Water flowing from the dam through canal systems transformed arid Cassia and Minidoka counties into “Idaho’s Breadbasket,” producing an economic impact of more than $1 billion annually.

After a hiatus during the COVID-19 pandemic, tours of the facility have resumed. Visitors often stand in silent awe inside the cavernous Allen E. Inman Powerplant, the tour’s grand finale.

“The sheer size and magnitude of the structure and internals—the force of the river spinning turbine blades to power generators and produce electricity—are really impressive,” says Cody Sibbett, operations and maintenance planner at the Bureau of Reclamation’s Upper Snake Field Office in Heyburn.

During tours of the dam and adjoining power plants, Cody says people often tell him they no longer take electricity for granted. They also have a deeper appreciation for the complexity of electrical production and the behind-the-scenes employees who maintain the dam and its accompanying structures. Cody says he is grateful electricity flows to his home near Albion from Raft River Rural Electric.

From a viewing deck inside the power plant, visitors look down 30 feet to two massive 10-megawatt horizontal shaft Kaplan generating units that emit a steady, powerful hum. Combined with two other units nearby in the original power plant, the four units have a generation capacity of 28.5 megawatts with a combined flow of 8,670 cubic feet per second.

Above the monoliths, a 20-by-38-foot American flag drapes from the wall, a tribute to the federal government’s foresight and American engineering ingenuity that established the Minidoka Project. The dam and irrigation canals, completed in 1906, are the cornerstone of the vast project, which encompasses seven dams in eastern Idaho and western Wyoming and hydroelectric power plants at Minidoka and Palisades.

Cody and his colleagues tell visitors of the dam’s and the power plants’ national significance and their roles in maintaining and operating the system.

Beginning in 1904, engineers and laborers toiled two years to build the dam at Minidoka Falls. The stalwart structure is 86 feet tall, 736 feet long, 412 feet wide at its base with a 2,300-foot-long spillway. It was the first embankment dam built by the U.S. Reclamation Service, an agency President Theodore Roosevelt established in 1902 to irrigate the arid West.

The Minidoka Dam staff is, from left, Nathan Davis, Jason Takeshita, Steve Mazur, Donovan May,Joe Fisher, Kevin Watson, Cody Sibbett and Kerry Strunk.
The Minidoka Dam staff is, from left, Nathan Davis, Jason Takeshita, Steve Mazur, Donovan May, Joe Fisher, Kevin Watson, Cody Sibbett and Kerry Strunk.

The original power plant, completed in 1909, was the first federal power plant in the Northwest. It also holds the distinction of being Reclamation’s oldest operating hydroelectric facility nationwide. In 1974, it was named to the National Register of Historic Places.

With water flowing from the dam, farmers in Cassia and Minidoka counties created “Idaho’s Breadbasket” full of crops renowned for variety, volume and value, according to the 2017 Census of Agriculture.

In Cassia County, farmers and ranchers brought in $927 million in farm cash receipts in 2017, making it the top county in Idaho in that category, according to the census. The county ranks as a top producer of potatoes, dry edible beans, sugar beets, corn silage, alfalfa, wheat and barley.

Minidoka County is first statewide in sugar beet and sheep production. Its farmers and ranchers tallied $354 million in farm-gate receipts in 2017.

On his morning commute throughout irrigation season, Cody describes seeing rows of sprinklers stretching to the horizon, watering countless acres of crops.

“Seeing that water and knowing it comes from our system and enables farmers to grow our food gives me a lot of job satisfaction,” he says. “It’s personal to me because I know the farmers from having grown up in the area and my dad working for a canal company.”

He says a local billboard reminds motorists, “If you eat, you’re involved in agriculture.”

During irrigation season from March to October, his colleague Jason Takeshita monitors precise waterflows.

“This dam’s primary purpose is to convey water for agriculture,” says Jason, the bureau’s operations and maintenance power plant supervisor. He transferred from Hoover Dam in August 2021.

“At Hoover, the priority is maintaining grid stability for the Southwest and minimizing power fluctuations,” he says. “Here, water conveyance takes priority, and water orders change frequently during irrigation season. Water flowing through the system is tracked to the acre foot on a daily basis. Electrical power is a byproduct of this conveyance.”

While the dam and canals were originally built for farming, the project’s mission expanded when a power plant was finished in 1909. Irrigation water could then be pumped to more areas, and electricity could be provided to Heyburn, Rupert and Paul, the townsites the bureau laid out.

“Some people don’t realize they were among the first rural towns in the United States to have electricity,” says Kerry Strunk, the dam and power plant facility manager.

In 1914, Rupert High School students had electrical tools in their woodshop and electric stoves in their domestic science programs, a technological feat for that era. Students and teachers relied on electricity to heat and light the building.

Part of the original power plant has been preserved as a museum to pay tribute to visionary farmers’ accomplishments.

“It’s amazing what they did,” Kerry says, showing posters of farm families working in their fields. “It’s an honor to be part of the team that continues what they started and to serve communities by providing irrigation water and electricity.”

Kerry leads visitors through the plant to the five original generating units, which were retired in 1995 and replaced with two rebuilt units. In 1997, two additional units began operating in the Allen E. Inman Powerplant, named for a dedicated employee who died in a plane crash with other Reclamation employees before the facility was completed.

To keep the system maintained and modernized, Cody says the team is always monitoring structures and prioritizing projects.

The spillway was replaced with 15 radial gates, a four-year project completed in 2015.

“We’re dedicated to keeping the Minidoka Project operating, just like those who came before us,” he says.