 Made of concrete and steel , the dam is 2 @,@ 335 m ( 7 @,@ 661 ft ) long and the top of the dam is 185 metres ( 607 ft ) above sea level . The project used 27 @.@ 2 million cubic metres ( 35 @.@ 6 × 10 ^ 6 cu yd ) of concrete ( mainly for the dam wall ) , 463 @,@ 000 tonnes of steel ( enough to build 63 Eiffel Towers ) and moved about 102 @.@ 6 million cubic metres ( 134 @.@ 2 × 10 ^ 6 cu yd ) of earth . The concrete dam wall is 181 metres ( 594 ft ) high above the rock basis . 
