That's just a Western pipe dream. The water crisis could trigger a revolt but the fundamentals for such revolt have to be there rather than the water crisis being the sole reason.

> people of Tehran will either need to move or die

No. I've lived (along a million other people) without water for many months during a hot summer episode. It was a major lifestyle degradation (and major doesn't even begin to describe it) but death was not a threat (though there was fear of disease spread due to possible degradation of sanitary conditions but that didn't happen either).