The general supervisor of the project was Roy Gausmann (1882-1974). Reginald H. Keays was the Head Engineer, Supervisor as well as Construction Engineer. He signed most of the designs that have been preserved to this day. Supervising engineers were also appointed for supplemental projects: two engineers for the Dam, four for the tunnel, one for the Galatsi plant, and one for the distribution network. The American engineers were in charge of the project and they held all responsible positions in each construction site. The Greek engineers were clearly outnumbered. They were hired due to their knowledge of the state mechanism and to their relevant significant work experience abroad.