In the western United States, water use and water rights questions associated with Native American communities are a major factor in the region’s future. Under federal law, these communities are entitled to substantial but often unquantified amounts of water. Planning for the future often gets tangled up in these questions.

For example:

Not all tribes in the Basin have adjudicated rights or settlements covering all of their tribal lands. In Arizona, five federally recognized tribal governments do not currently have quantified water rights: the Havasupai Tribe, the Hualapai Tribe, the Kaibab Band of Paiute Indians, the Navajo Nation and the San Juan Paiute Tribe. An additional six tribes do not have adjudicated rights or settlements for at least some of their lands: the Hopi Tribe, the Pascua Yaqui Tribe, the San Carlos Apache Tribe, the Tohono O’odham Nation, the Tonto Apache Tribe, and the Yavapai-Apache Nation.

That’s from the Inter Tribal Council of Arizona’s comments (pdf here) on the US Bureau of Reclamation’s draft Colorado River Basin Water Supply and Demand Study. The ITCZ also make a salient point that never occurred to me regarding water consumption under various economic scenarios being considered:

[E]conomic hardship that depresses population growth and thus M&I water demand in the large cities may result in tribal members who were living in those cities and become unemployed moving back to their tribal homelands, increasing M&I water demand there.