Arizona Water Augmentation - Part 6:Tribal water leasing
Since the 1980s, Arizona Tribes have leased water for off-reservation use by cities and industries. A Tribal water lease is an agreement through which a Tribe allows an entity to temporarily use part of the Tribe’s water allocation in exchange for payment. It is generally understood that authorization from Congress is required for Tribes to lease water off-reservation. [1] However, the choice to make a Tribe’s water available for lease is up to the Tribe.
Currently, six Arizona Tribes lease Colorado River water to eleven municipal water providers, two mining companies, one power company and the Central Arizona Groundwater Replenishment District.[2] Additionally, one Tribe leases water to another Tribe.
The amount of Tribal water made available through leases has varied over the years, but recently has totaled more than 150,000 acre-feet per year. For context, that is more water than is used annually by the city of Tucson or the city of Mesa to meet tap water needs.
Will more water become available through Tribal water leases?
In 2023, Congress approved legislation authorizing the Colorado River Indian Tribes (CRIT) to lease part of its high priority Colorado River allocation. This water could be conveyed via the Central Arizona Project canal to water users in Maricopa, Pinal and Pima Counties. As yet, no leases have been finalized. [3]
Likewise, the White Mountain Apache Tribe Water Rights Settlement Act authorizes the Tribe to lease 25,000 acre-feet of Colorado River water to various entities in central Arizona. Although the settlement was completed several years ago, it has yet to become effective and the leases have not been executed.
Currently, two new Arizona Indian water rights settlements are making their way through Congress: the Northeastern Arizona Indian Water Rights Settlement Agreement (NAIWRSA) and the Yavapai-Apache Nation Settlement Agreement (YANSA). Both of these agreements contain provisions authorizing additional Tribal leases of Colorado River water.
Not including NAIWRSA and YANSA, in total, about 300,000 acre-feet per year of Colorado River water could be made available through leases, should the Tribes wish it. However, the priorities of the water supplies that could be leased vary, and some lower priority supplies might not be available if shortage is declared.
For many Arizona Tribal members, water is more than a commodity: Water carries significant cultural and spiritual values that add unique considerations to a Tribal nation’s decision to lease its water. However, a Tribal water lease can be a mutually beneficial transaction between a Tribe and a lessee, providing a source of immediate, substantial revenue that the Tribe can use for economic development and community benefits as well as providing reliable water resources for central Arizona cities to meet the rigorous long-term water supply requirements for urban growth or to support investments in electric power production, mining or other industries.
In recent years, the federal government and other agencies have offered financial incentives to Tribes and other water users to leave their water in Lake Mead to protect against deep shortages on the Colorado River. If such programs continue, they might pose stiff competition for the same water that Tribes might otherwise make available for leasing.
The CRIT’s Colorado River rights are the highest priority in Arizona. If the NAIWRSA is approved by Congress, the Navajo Nation and Hopi Tribe will also secure high priority Colorado River water rights. Cities and industries facing potential reductions of lower priority Colorado River supplies in central Arizona may look to leasing higher priority supplies as a hedge against future cuts.
This blog series is co-sponsored by the Arizona Water Innovation Initiative, a multi-year partnership with the state led by Arizona State University’s Julie Ann Wrigley Global Futures Laboratory in collaboration with the Ira A. Fulton Schools of Engineering.
[1] Tribes need congressional authorization to lease their water off their reservations because the federal government holds these rights in trust for the Tribes, which means in many cases that it must approve or oversee major decisions like water leasing. United States v. Winans, 198 U.S. 371 (1905); see also Samuel Joyce, Tribal Water Sovereignty: Authorizing Indian Water Marketing in the Colorado Basin, Stanford Law and Policy Review vol 35:161 (2024) at 166.
[2] The Central Arizona Entitlements and Access tool on the Kyl Center’s Arizona Water Blueprint provides details about Tribal water leases.
[3] CRIT’s water rights were decreed in the US Supreme Court’s landmark 1964 decision in Arizona v. California.