The Xia Dynasty (c. 2070-1600 BCE) was the first government to emerge in ancient China and the first to adopt the policy of dynastic succession, making it the first dynasty of China.
The Xia Dynasty was overthrown by the Shang Dynasty (c.1600-1046 BCE), a more historically certain governmental entity, which was in turn overthrown by the Zhou Dynasty (1046-256 BCE).
The argument claiming the Xia Dynasty is a mythological construct claims that the Zhou (and later dynasties) wanted to make clear that the previous ones lost their right to rule through immoral conduct and so created a proto-dynasty - the Xia - as a pre historic model for this.
Many scholars today still maintain that the Xia Dynasty is a myth but seem to be at a loss to explain why the physical evidence uncovered argues against their claim.
Those who believe the Xia Dynasty was a reality are at an equal disadvantage in that none of the sites uncovered so far positively identify themselves as belonging to the Xia Dynasty and could as easily be interpreted as early Shang Dynasty buildings.
According to historians like Sima Qian, there was once a great ruler named Huang-ti (also Huangdi, `emperor') better known as the Yellow Emperor who emerged from the tribal system pre-historic China to rule the region of Shandong between 2697-2597 BCE.
The flood was a serious problem during Yao's reign in controlling the flooding of the Yellow River which disrupted agriculture as well as drowning or displacing his people.