In 1915, the Long Lake Dam was constructed by Washington Water Power (now Avista), on the Spokane River in order to produce hydroelectric power for eastern Washington and northern Idaho, playing a vital role in facilitating urban, industrial, and agricultural development. When the dam was constructed, it was it was considered the tallest dam in the world at 213ft and one of the earliest hydroelectric generating facilities in The Washington Water Power Company's electrical power generating network. Since its construction in 1915, the dam had been untouched by construction and other renovations until 2016.
The Long Lake Hydroelectric Plant and its setting have remained largely unaltered since its original construction in 1915. The historic property was nominated to the National Register of Historic Places in 1988 and currently holds a place in the national registry. Constituent elements include the spillway dam, control dam (intake), cut-off (arch dam), and the four brick operating houses situated on top of the spillway dam.
The Spokane River was once home to the spawning grounds of Chinook salmon, and for centuries provided for local Indian tribes throughout the area. Of the one million salmon to spawn annually, upwards of 300,000 of these were harvested by tribes. For centuries, before the rise of the dams in the late 1800's, Spokane Falls and its surrounding area was a central hub for trading and fishing. The Spokane people shared this territory with many other tribes, including the Colville, Flathead, and Kalispell. Before the implementation of dams on the Spokane, many Natives would fish at Kettle falls, located miles upstream of the Spokane tributaries.
The Spokane Indians were salmon people. The tribe was arranged into three distinct bands along the lower, middle and upper reaches of the river according to the location of historic salmon fishing sites. While relations with their neighboring tribes, particularly the Coeur d’Alenes, were at times strained, salmon fishing and salmon trading brought the Spokane Natives into contact with many other tribes, sometimes from far away. It was not unusual for up to 1,000 Indians to participate in these salmon harvests.