“we let the first farmer along the river to possibly use more water”
Interestingly that is the law nowhere in the US. In the East, upstream users cannot damage the interest of downstream users. (Not usually an issue because there are not general water shortages.) In the west, however, water is an owned commodity and water rights are separate from other property rigths. You may be stealing someone else’s property if you eat a snowball made from newfallen snow!