Long Lake Dam is a concrete gravity dam on the Spokane River

Spokane River

The Spokane River is a tributary of the Columbia River, approximately long, in northern Idaho and eastern Washington in the United States. It drains a low mountainous area east of the Columbia, passing through the city of Spokane, Washington.-Description:...

, about 30 miles (48.3 km) northwest of Spokane

Spokane, Washington

Spokane is a city located in the Northwestern United States in the state of Washington. It is the largest city of Spokane County of which it is also the county seat, and the metropolitan center of the Inland Northwest region...

 in eastern Washington. It forms Long Lake

Long Lake

-Canada:Long Lake and its French language equivalent, "Lac Long", is the most commonly used name for a geographical feature in Canada. There are 203 Long Lakes and 164 occurrences of Lac Long...

, a 23.5 mi (37.8 km) long reservoir, and has a hydroelectric generating capacity of 71 megawatts. The dam was built by Washington Water Power (now Avista Utilities), which operates five other dams along the Spokane.

Upon its completion in 1915, Long Lake Dam completely blocked salmon

Salmon

Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

 migrations to the upper portions of the Spokane River watershed, although much larger Grand Coulee Dam

Grand Coulee Dam

Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...

 on the Columbia River

Columbia River

The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

extirpated salmon from the entire Spokane basin by 1942.