BBC: Perth is blessed with abundant water – but most of it is the salty stuff you sail on Authorities in Western Australia say they can show the world how to conquer a water crisis that had threatened to decimate the state capital, Perth, amid a long-standing drought and declining rainfall. Turning the sea into drinking water is at the heart of Western Australia’s multi-faceted approach to satisfying the thirst of a booming population that lives on the edge of a desert. It’s not …