So they would need to build a pipeline through Mexico and then purify the water? Because if they used raw sea water it would likely cause problems as the evapo

So they would need to build a pipeline through Mexico and then purify the water? Because if they used raw sea water it would likely cause problems as the evaporated spray left salt. How much energy is it going to take to build that pipeline, pump water in and purify it? It's a cool idea, don't get me wrong. I just wonder where the water is coming from. That whole area already doesn't have enough water.