In Spokane as elsewhere, waterpower was the driving force behind industrial development. The dam and powerhouse at Nine Mile Falls are key pieces of Spokane history. This dam and its builder, Jay P. Graves, provided power for streetcars, electric lights, and factories of early Spokane.
Graves was an industrious man with an entrepreneurial spirit. He came to Spokane in 1887 and speculated in real estate. He profited during the stock market crashes of 1892, investing in other industries in the Spokane area, such as railroads and streetcars. In 1902 Graves purchased The Spokane & Montrose, the first motorized street railway in Spokane. He renamed it the Spokane Traction Company. Graves's new company purchased power from Washington Water Power, who held a monopoly on the sale of power to the area and was a competitor in the railway business.
Graves decided to establish his own electric utility, The Spokane and Inland Empire Power Company. He purchased a site on the Spokane River about nine miles north of the city and put his plan into motion. The Nine Mile Falls Dam was sixty feet high and built at a cost of between $800,000 and $1,000,000. Construction was completed in 1908.
The power harnessed from Nine Mile Falls was used to power Grave's electric interurban railways, which eventually grew to serve much of Eastern Washington and Northern Idaho. By 1907 Graves's railway system operated on over two-hundred miles of track radiating from Spokane. By 1912 the lines stretched two-hundred and fifty miles. These railways, powered by the Nine Mile Dam ushered in the modern era of Spokane, placing it in line with many of the more developed larger cities in the United States.
Graves sold off his interest in the plant in 1911 and it was purchased by the Washington Water Power Company in the mid-1920s. He kept his railroad holdings, but the battle for hydroelectric power was won by the Washington Power Company.
Collectively the complex is one of the best preserved historic power sites in the state. The original generators are still in use. It is even listed in the national Register of Historic Places. The Dam was modernized in 1950, but still retains many original working elements.