Colorado River Basin Ten Tribes Partnership Tribal Water Study

Quick Links:

In 2014, The Bureau of Reclamation’s Upper Colorado Region and Lower Colorado Region, in collaboration with the 10 member tribes of the Colorado River Basin Tribes Partnership, commonly referred to as the Ten Tribes Partnership (Partnership), began the Colorado River Basin Ten Tribes Partnership Tribal Water Study (Tribal Water Study).The Tribal Water Study builds on the scientific foundation of the Colorado River Basin Water Supply and Demand Study (Basin Study) and advance critical information about the member tribes beyond the limited assessment of tribal water in the Basin Study.

The tribes of the Partnership hold a significant amount of quantified and unquantified federal reserved water rights to the Colorado River and its tributaries. In addition, there are unresolved reserved water rights claims and some tribes hold water rights that are not federal reserved water rights. Reclamation did not intend that the Basin Study be used to assess the future impacts of tribal water use in the Basin, and the Basin Study did not fully account for tribal water demand, reflect the potential use of tribal water presently used by others, or show the potential impact on the Basin water supply if a substantial amount of the presently unused or unquantified tribal water is used by the tribal water rights holders by 2060. In recognition of the importance in bringing the tribal perspective to bear in furthering the understanding of these important matters, Reclamation and the Partnership committed to developing and completing the Tribal Water Study as documented in the Agreement Regarding the Importance of the Colorado River Basin Tribal Water Study.

The Study documents how Partnership Tribes currently use their water, projects how future water development could occur, and describes the potential effects of future tribal water development on the Colorado River System. The Study also identifies challenges related to the use of tribal water and explores opportunities that provide a wide range of benefits to both Partnership Tribes and other water users.

Partnership Tribes have reserved water rights, including unresolved claims, to divert nearly 2.8 million acre-feet of water per year from the Colorado River and its tributaries. These rights are, in general, the most senior water rights in the Basin and therefore some of the most protected from shortage.  Partnership Tribes currently divert nearly 1.4 million acre-feet of water per year, almost all of which is used for agriculture.  As they look into the future, most tribes anticipate diverting their full water rights by 2040. 

Although many of the Partnership Tribes do not currently use all their reserved water rights and have not developed the yet unquantified water rights, such tribal water does not go unused.  The full development of tribal water rights for tribal benefit will widen the future gap of projected water supplies and demands; however, the modeling indicates that the effect of tribal water development in the Basin is not as significant as full development of the state apportionments in the Upper Basin and the projected effect of climate change. 

The Study revealed disparities among the Partnership Tribes, and between the Partnership Tribes and other water users in the Basin.  These disparities have created barriers to the full development of federal Indian reserved water rights that include access to funding and capital markets for development, the lack of - and poor condition of - existing infrastructure, the number of tribal members and reservation residents without access to clean drinking water and adequate sanitation, and legal restrictions.

The Study Report, released in December 2018, includes perspectives and positions from each of the Partnership Tribes as statements from the Tribe’s individual perspective.

The Ten Tribes Partnership was formed in 1992 by ten federally recognized tribes with federal Indian reserved water rights in the Colorado River or its tributaries. Five member Tribes are located in the Upper Basin (Ute Mountain Ute Tribe, Southern Ute Indian Tribe, Ute Indian Tribe, Jicarilla Apache Nation, and Navajo Nation) and five are in the Lower Basin (Fort Mojave Indian Tribe, Colorado River Indian Tribes, Chemehuevi Indian Tribe, Quechan Indian Tribe, and Cocopah Indian Tribe).

Back to Colorado River Basin Water Supply and Demand Study

Last Updated: 12/13/18