BS meter is pinging.
10,000 years old+, feeding 5 billion people?
i think not.
... entirely possible!
I love it, if it was you are right... the rest of the evidence would be there. The parked equipment used to do the trenching, the maintenance equipment, the sheds, the pumps/valves control systems, the source of the water, the harvesting / processing/storing facilities. The residences, the social infrastructure..... government structures, libraries, museums,..... streets/ streetlights....etc etc.
All those things would be visible.
In the absence, it’s all horseshit.