GAINT BUDDHA MONK
Construction was started in 713, led by a Chinese monk named Haitong. He hoped that the Buddha would calm the turbulent waters that plagued the shipping vessels traveling down the river. When funding for the project was threatened, he is said to have gouged out his own eyes to show his piety and sincerity. After his death, however, the construction was stuck due to insufficient funding. About 70 years later, a jiedushi decided to sponsor the project and the construction was completed by Haitong's disciples in 803.
Apparently the massive construction resulted in so much stone being removed from the cliff face and deposited into the river below that the currents were indeed altered by the statue, making the waters safe for passing ships.