It stopped raining in the inland valleys of Peru. Spelled death for those societies. And there was nothing men could do to either stop it — or cause it.
I don’t think it ever rained much in those valleys. Not since people have lived there, anyway.
The original civilization seems to have been based mostly on catching fish and eating it. The main crop was cotton for nets. It was grown on irrigated land, so the only drought that would affect them much was if it were to stop snowing in the Andes, kind of like it has in the CA Sierra. Which is possible I suppose.
The city nearest this site averages about an inch of rain per year.