As I said it is a personal view, and while I accept it could be wrong I rather like the idea that they were so clever they worked out how to preserve clean water. Not just for drinking, bathing, and enough to make lemonade for the annual olympics, but the incidence of spina bifida was massively high in this period in this region (see Don Brothwell, the archaeo of disease), and a pool of clean water would have been a major benefit for these people too.

This could all be bollux of course !

VBB

PS Yes it was a hydrologist Ish' now you mention it.