Anyone know what is more economical? Many areas of the world are flooded, but many are experiencing extreme drought. Can you move enough water from one to another? Is it cheaper to transport dirty fresh water by aqueducts to drought areas, then purify the water? Or is it cheaper to desalinate local sea water? The Romans built aqueducts in ancient times the hard way. Today we have earth moving equipment. Why not build aqueducts to transport fresh (but dirty) water hundreds of miles?