 Site clearing and foundation work would have been scheduled to begin after completion of the diversion work in the seventh year of the project . The first pouring of concrete was scheduled for the project 's eighth year , and work on the powerhouse would have begun in the 11th year . Owing to the large size of the reservoir , engineers estimated that the diversion tunnels would be closed in the 13th year , allowing construction to pace the filling of the new lake . The reservoir would have reached a pool elevation of 550 feet ( 168 m ) in the 21st year , the dam would have been completed to elevation 660 feet ( 201 m ) in the 25th year , and the reservoir would have been filled to the full 640 @-@ foot ( 195 m ) level in the 31st year after the project 's start . The installation of power generators was planned to follow as needed , with the last unit scheduled for installation by the 45th year of the project . 
