Much of the confusion over Native American water rights in the United States can be traced to Winters v. United States, the 1908 Supreme Court decision that first established those rights. In one part of this decision, the Court seemed to suggest that Native Americans were entitled to all the water flowing in rivers bordering or entering their reservations. Elsewhere in the decision, the Court stated that Native Americans had rights only to an amount of water from such rivers sufficient for irrigation purposes. There was obviously a considerable difference between the two positions. But even if one assumed, as most attorneys have since, that the Court intended to set a limit, its nature was far from clear. What exactly did the Court mean by "irrigation purposes"? Did it mean the irrigation needs at the time of a reservation's creation? Or at the time of the Court's decision? Or was the decree open-ended and intended to guarantee Native Americans additional water (or perhaps less water) as their population grew (or declined) and their agricultural needs along with it? If meant to be open-ended, then did this not create a hardship for non-Native Americans? How, for example, could they proceed to make costly investments to develop their lands if at any time the courts could deprive them of water needed by a nearby reservation? Alternatively, if Native American rights to water were to be determined by irrigation needs (whether past or future), did this not constitute an unjust restriction on Native Americans? Should they, for example, be required to use their water for irrigation when they might prefer to use it for other pursuits, such as mining or fishing? A related unanswered question that emerged as competition for water increased in the arid western United States was Native Americans' right to water beneath the ground: did the right include only surface streams, or did it extend to the groundwaters that often determined the amount of water flowing in streams? Could Native Americans prevent non-Native Americans from engaging in groundwater pumping close to a reservation, if that pumping diminished the reservation's surface water supplies? Such crucial questions have given rise to dozens of conflicting decisions in both lower and higher courts.
