A look at Swan Falls Dam: Then and now

If you think a century-old power plant is a weird place to go for a daytrip, chances are you’ve never been to Swan Falls. Swan Falls Dam — thought to be named after a prospector named P.M. Swan, who filed for a placer mine near the rapids in 1892 — is located about 20 miles from Kuna on the Snake River. It was the first of 17 dams to be built on the Snake River and its tributaries.

The history of the dam and power plant

One of the earliest built in the Pacific Northwest, Swan Falls Dam was constructed in 1901 by Trade Dollar Consolidated, a Silver City mining consortium, with the intention of providing electricity to the Silver City gold and silver mines after the area ran out of wood for fuel. The three-phase electricity used by the dam was the testing ground for modern electricity because the alternating current advocated by Nikola Tesla was better able to traverse the distance between the dam and the city than the direct current supported by Thomas Edison. But the electricity had only recently become available when mining stopped, and went on to be used for things such as the interurban public transit system in the Treasure Valley.

The powerhouse itself was built in three sections, originally designed by Andrew J. Wiley, an irrigation engineer and the assistant of engineer Arthur D. Foote. The first building was constructed in 1900, the second in 1906, then one in 1910, after which the original was replaced in 1911-1913. In 1910, Trade Dollar investors organized the Swan Falls Power Co. and added two new generators. Idaho Power acquired Swan Falls in 1916 during a consolidation of southern Idaho power companies in receivership, expanded the capacity of the dam — which, at the time, had the largest generating capacity in the state — and added new equipment in two phases.

New spillways were built in 1914, and in 1919, Idaho Power workers began to rebuild the old wooden spillway dam between the lava island and the left shore of the falls. A new concrete dam replaced the original wooden crib in 1920, and in 1936, the rocky outcrop on the east side of the river was excavated for an additional spillway and 10 new gates. A concrete fish ladder, intended for salmon, was also built in 1922, but it is not typically used. The dam and power plant were rebuilt in 1994 to update the equipment. Before that, the powerhouse was used as a training assignment for new Idaho Power workers because of the variety of manually operated equipment at the site, including generators installed as long ago as 1918.

Swan Falls today

Presently, the dam is 1,150 feet across and 107 feet high, with a surface area of 1,525 acres, and the reservoir catchment area covers 41,900 square miles. Swan Falls is also an important part of Idaho’s water rights history. Because the dam’s water rights were never subordinated to those of future irrigation projects upstream, Swan Falls was the focus of a water use and water rights conflict during the 1970s and 1980s, the resolution of which altered the course of economic development and water use in southern Idaho.

Now, the dam and surrounding area have additional uses. When the plant was rebuilt, the area around Swan Falls gained a number of amenities for day and even overnight trips. Idaho Power adds and maintains these amenities as a part of its stewardship responsibilities related to its federal license, which it updates every few years through the Federal Energy Regulatory Commission (FERC), according to Fred Noland, Idaho Power recreation supervisor. In the wake of 9/11 in 2001, access to the functioning powerhouse was restricted as a security risk, but the museum and its surrounding areas are still open (pending COVID-19 closures).

“Most of the current park areas was the original village for the project — where most of the plant workers lived,” said Ty Corn, Idaho Power archaeologist. “At one time, there were about a dozen cottages in the area of the park. The village also included fruit trees, a large garden and a few farm animals — all necessary for making a living in the remote location. With the completion of the new plant in 1994 and the general expectation that hydro projects offer more public recreation opportunities, the village was moved upstream away from the dam, and the former village area was converted into a park. All the cottages were removed, but the boardinghouse remains, and it is one of the oldest buildings in the Idaho Power system.”

Day-use and overnight amenities

Amenities available at the Swan Falls area include:

• Two boat ramps — one for the reservoir and one for the area below the dam
• 20 overnight dispersed campsites (free)
• Interpretive panels about resident fish, Native Americans and power plant history
• Day-use park with reservable picnic shelter
• Fishing pier
• Equestrian parking area

A number of the amenities were recently updated with the most recent application for its FERC license, Noland said. “The campsites, boat ramps (and associated parking areas), new interpretive panels and the fishing pier were all completed in 2014; the equestrian parking was completed in 2015.”

Some of the amenities are accessible for the disabled, Noland said. “Our recreation plan includes ways we accommodate those with disabilities,” he explained. “We have designated parking, accessible restrooms, walkways and routes to connect all major amenities, including the picnic shelter, parking, restrooms, interpretive panels and the fishing pier.”

In addition, Swan Falls is within the Morley Nelson Snake River Birds of Prey National Conservation Area (NCA). The canyon is home to the largest population of nesting raptors in North America, with 16 species nesting and eight migrating or wintering. An especially good time to look for birds is from March through June. The area was designated as the Snake River Birds of Prey NCA in 1993, spanning 600,000 acres, and was named after raptor naturalist Morley Nelson in 2009 after his death in 2005.

And Idaho Power isn’t done with providing amenities to the area. “We take an adaptive, collaborative approach to planning facilities,” Noland said. “This is a culmination of visitor survey results, our trend monitoring and input directly from agencies and user groups (nonprofits or clubs).”

Take in the historical sites 

For history and power buffs, the powerhouse itself, as well as the original worker clubhouse and boardinghouse, are also worth checking out. When the new powerhouse was built in 1994, the old one was converted to a museum, Corn said. As such, it’s a treasure trove of information about how both the original and updated powerhouse were built, how the dam itself was built and the history of electricity in that part of Idaho.

Starting in the 1910s, the power company built houses for the workers, which were remodeled as recently as the 1950s. Because of the distance from Kuna, workmen brought their wives and families with them. The cottages were designed by Idaho Power engineers (rather than architects), who used material from magazines like Architectural Record, Building News, Ladies’ Home Journal and Architectural Forum for ideas.

The residential area included flowering shrubs, vegetable and rose gardens, grape arbors, pasture and animal enclosures, a fruit orchard, a playground, clotheslines, outdoor fireplaces and sheds, according to a report on the area from the federal government. In 1938, the area housed enough children to support a school. The families also sold fruit and vegetables locally for extra money. Sadly, the houses have been torn down except for the boardinghouse, built in 1901, which originally had six bedrooms, two bathrooms, a kitchen and a common dining area.

The next historic amenity to be added is likely to be the boardinghouse, which underwent extensive restoration in the past few years. “Restoration is complete,” Corn said. “Idaho Power plans to make it available to public visitation at some point in the future, but we don’t have a timeline right now.”

Moreover, the museum itself is likely to be updated over the next few years. “We are in the process of developing a plan for renovating and upgrading the museum,” Corn said.

Meanwhile, the dam and powerhouse are still in use. “Swan Falls is very much still part of our generating fleet,” said Brad Bowlin, Idaho Power spokesman. “It once had 10 generators with a capacity to put out a little over 10 megawatts of electricity.” Now, the powerhouse’s two turbines have a combined capacity of 27.2 megawatts, he said.

How to get there

From Boise, take I-84 west and take Exit 44 south on Highway 69 (Meridian Road) toward Kuna. From Kuna, take Swan Falls Road south for about 20 miles. Turn right at the Swan Falls Road dirt extension and take it (carefully) down the hill to the dam. (Look to the left about halfway down the hill to see what happens if you aren’t careful.)

(When you drive down the road, keep in mind that the turbines for the first dam in 1901 were hauled down that road by horse and wagon.)

*This article originally appeared in Idaho Business Review’s Treasure Valley Living magazine.