@AskPippa I don't know that there are places with THAT much excess water that they can irrigate a desert (it's not working so well in California this past decade), but we're also talking about quantities of water that are VASTLY larger than what a pipeline carries. The entire flow of multiple rivers.
Better to learn to live within our means and take proactive steps to manage our water resources responsibly, a task that Alberta is uniquely unsuited to tackling.