Construction continued and on September 13, 1963, the dam was topped out. Work on the power plant and spillways began directly after the dam wall was complete. The spillway tunnels were excavated around both abutments of the dam, dropping steeply from their control gates on Lake Powell to merge with the lower ends of the diversion tunnels. This measure saved cost, but introduced a weak point where the two tunnels intersected. The upper ends of the diversion tunnels were then sealed with solid concrete. The first electricity was generated on September 4, 1964, with the power sent into the regional electric grid through a pair of long-distance transmission lines as far as Phoenix, Arizona and Farmington, New Mexico. It took two more years to complete all remaining aspects of the project. On September 22, 1966 Lady Bird Johnson gave the official dedication speech for Glen Canyon Dam, before a crowd of 3,000 people.