The Mount Emei Scenic Area, including Leshan Giant Buddha Scenic Area has been listed as a UNESCO World Heritage Site since 1996.
The stone Leshan Giant Buddha faces Mount Emei, with the rivers flowing below its feet. It is the largest and tallest stone Buddha statue in the world and it is by far the tallest pre-modern statue in the world.
Construction was started in 713, led by a Chinese monk named Hai Tong. 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 Hai Tong'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 water safe for passing ships.
A sophisticated drainage system was incorporated into the Leshan Giant Buddha when it was built. It is still in working order. It includes drainage pipes carved into various places on the body, to carry away the water after the rains so as to reduce weathering.
When the Giant Buddha was carved, a huge thirteen story wood structure (similar to the one at the Rongxian Giant Buddha) was built to shelter it from rain and sunshine. This structure was destroyed and sacked by the Mongols during the wars at the end of the Yuan Dynasty. From then on, the stone statue was exposed to the elements.