Great so show us the basis for the claimed dates! Ha.
Irrigation did start early on the Euphrates and Tigris, and as early as 3000 BCE. And on the Nile, Egyptians also used irrigation to channeled waters to their crops.
But it my understanding that it was the farmers from the Indus Valley civilization started irrigation as early as 4000 BCE or even earlier. However, my knowledge on the Indian subcontinent is limited, so you may want to ask someone else who know more about India’s prehistory.
Anyway, the cities of Uruk (Erech), Ur, Eridu and Nineveh, all predated 3000 BCE.
Because Uruk was the largest city in the world during the 4th millennium BCE, it was known as the Uruk period (c 4000 - c 3100 BCE). Around 3200 BCE, a ziggurat was constructed in the Anu District of Uruk, with the White Temple on top of the ziggurat.
And the cuneiforms older than the Sumerian cuneiforms were found in Uruk in 3400 BCE, which archaeologists and anthropologists referred to as proto-Sumerian cuneiforms. Actual Sumerian cuneiforms originated in Jemdet Nasr, dated as early as 3100 BCE. Hence, the period (c 3100 - 2900 BCE) was named after this little town.
You can laugh at these dates, but you have no evidence to support anything in regarding to the (dates to) events in the Bible, particularly Genesis and Exodus. And the ages of the patriarchs in Genesis 5 and 8 (Noah) are terribly distorted and exaggerated.