The US Court of Appeals for the Tenth Circuit ruled in favor of three Pueblo Indian tribes Tuesday in a water rights case.

The decision is part of a nearly 40-year-old dispute over water rights in the Jemez River Basin in central New Mexico. The pueblos of Jemez, Santa Ana and Zia claim those rights, and the US initiated the case on the tribes’ behalf. It was just a single discrete issue that came before the Tenth Circuit, however: “whether the Pueblos’ aboriginal water rights were extinguished by the imposition of Spanish authority without any affirmative act.”

The district court had found that the Pueblos did have aboriginal water rights, that is, property rights of indigenous people that are maintained even after another sovereign assumes control. However, the court also found that Spain had extinguished the tribes’ rights, even though Spain never undertook any affirmative act to decrease the amount of water the Pueblos could use. The Tenth Circuit, in reviewing US case law regarding the extinguishing of aboriginal rights, found that it was always a matter of an affirmative action, and that, “[n]o matter the method used, the sovereign’s intent to extinguish must be clear and unambiguous.”

Looking to the historical record, the Tenth Circuit found that Spain had general principles and systems for the administration of water, but that none of them specifically mention any Native American tribes, let alone the three Pueblo tribes in this case. In fact, the record shows “no evidence that Spanish sovereignty had any impact on the Pueblos’ use of the water from the Jemez River at all.” The Tenth Circuit remanded the issue back to the district court, noting that this decision only holds that Spain did not extinguish the tribes’ water rights. The matter of whether Mexico or the US, as subsequent sovereigns over the tribes, extinguished their rights still has to be determined.