Complex sentence: The project to build the station was launched in the fall of 1974, the Morrison Dam was constructed between 1975 and 1977 ro provide cooling water for the station, with work on the power house starting in 1975.
Split into simpler sentences: The project to build the station was launched in the fall of 1974. The Morrison Dam was constructed between 1975 and 1977 ro provide cooling water for the station, with work on the power house starting in 1975.