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Resolution of Arizona's Disputed Water Rights

The extent of resolution of Arizona’s disputed water rights is measured by the number of Hydrographic Survey Reports (HSR) completed by Arizona Department of Water Resources for the 10 basins within the adjudications.

Disputed or unresolved water rights present challenges to insuring a long-term water supply. Western water law is based on the concept of “prior appropriation,” which means that whoever was first to use surface water gets to keep it.

Across the state, water in many streams and rivers is overallocated, meaning that there are more claims to the water than is available. To resolve this, a “general stream adjudication” is necessary. This litigation is a complex process to determine water rights, involving all claimants who feel they have a right to the water. Claimants then rely on the court to determine who will ultimately have water rights. In Arizona, the Little Colorado and Gila rivers are proceeding through a general stream adjudication process that started in the 1970s.

One important step in this process is the publication of a Hydrographic Survey Report (HSR) which provides information about the condition of the watershed, the claims that are made on the water, and a recommendation from the Arizona Department of Water Resources regarding the rights of individual claimants. With this report, the “Special Master” can recommend to the assigned judge a resolution through a final decree that settles the water claims. Completion of the adjudications is important in that rivers and streams flow within the limits of their annual yield, and water users have increased confidence in the amount of water that they are allowed to use. Water markets can then allow more efficient use of water.

Extent of Resolution of Arizona’s Disputed Water Rights is updated annually and is available for Arizona’s 10 basins within the Little Colorado and Gila rivers adjudications with an annual comparison to the previous year.