One of the ways you can claim rights to water sources is to own land next to them or over them. It seems intuitive that you should be able to dip into a river running along your property to get a drink for yourself and possibly your livestock, or water for your plants and possibly your farm fields. That works so long as you don't hog too much of the river flow and your downstream neighbors can do the same as you are doing. In practice, there are so many humans today demanding so much water that the amounts each person or enterprise can withdraw…