But then you need a somewhere sunny, with low land prices on a coast with a large demand for fresh water. Otherwise you have to pipe the fresh water uphill to

But then you need a somewhere sunny, with low land prices on a coast with a large demand for fresh water. Otherwise you have to pipe the fresh water uphill to the inland cities - much easier to pipe it downhill from the mountains. Apart from Australia, agricultural bits of california and some parts of the middle east there aren't many places that fit.