Mencius
The Book of Records says: "The inundation alarms me."  "Inundation" means "flood waters." Yü was employed to manage  the flood. Yü dredged the earth and conveyed the water to the sea. He drove away the snakes and dragons and exiled them to the marshes. When water traveled through the land it formed the Yangze River, the Huai River, the Yellow River, and the Han River. Since the [marshes] were in remote and cut off places, the depredations visited upon humans by birds and beasts were eliminated, and after that humans got to live on the plains. [However,] after [people's memories of] both Yao and Shun fell into obscurity the way of the sages went into a steep decline.