 Materially , building the dam would have required 15 @,@ 000 @,@ 000 cubic yards ( 11 @,@ 470 @,@ 000 m3 ) of concrete aggregate , 2 @,@ 900 @,@ 000 cubic yards ( 2 @,@ 220 @,@ 000 m3 ) of rock fill , and another 1 @,@ 700 @,@ 000 cubic yards ( 1 @,@ 300 @,@ 000 m3 ) of various other types of fill . Engineers suggested that some of the material could be found at the site , but the remainder would have to be brought from outside sources . 
