This is a picture of the downstream side of Morelos Dam, on the U.S. Mexico border west of Yuma, Ariz. I took it in March, when there was water flowing downstream, into Mexico. That is an unusual sight. This is usually the point where the Colorado River ends.
It’s not entirely clear to me where in this picture the actual U.S.-Mexico border is – out there somewhere underwater. Normally this is not much of an issue, though I’ve been there when it’s dry and there’s no less clarity on the land itself. I’m pretty sure the day I was there when it was dry I crossed back and forth between the two countries on foot without realizing it quite a few times.