Which of the following is not correctly matched? Dams - Rivers

Option B is the wrong match. Hoover Dam sits on the Colorado River in the Black Canyon, on the Nevada-Arizona border, and was completed in 1936 for flood control, water storage and hydropower. The Tennessee is the river of the Tennessee Valley Authority, which built its own dams such as Wilson and Norris, but Hoover is not one of them.

The other three are correctly matched. Grand Coulee on the Columbia River in Washington State is among the largest hydroelectric plants in the United States. Nurek on the Vakhsh River in Tajikistan is one of the world's tallest embankment dams. Cahora Bassa on the Zambezi in Mozambique is a major hydropower project that supplies power to South Africa.

The core concept is that major dams are identified by their river basin, and this question tests basin-level geography of hydropower. It connects to GS-I rivers and to the GS-III debate on hydropower and inter-state water sharing.

Trap: Aspirants see the word Tennessee and assume it is the Hoover river because of the TVA association. Remember that TVA dams sit on Tennessee tributaries, while Hoover is on the Colorado.