What legal doctrine typically governs new water claims in Arizona?

The legal doctrine that governs new water claims in Arizona is the doctrine of prior appropriation. This principle is based on the idea that water rights are allocated based on the priority of use, meaning that those who first put the water to beneficial use have the first claim to it. In Arizona, a state with limited water resources, this doctrine is crucial as it allows for a more structured and fair allocation of water, which is essential for agriculture, urban development, and other uses reliant on water availability.

Under prior appropriation, water rights can be severed from the land and transferred, promoting efficiency and enabling water to flow to its most beneficial use. Claims to water must be established through a legal process with demonstration of beneficial use; thus, this doctrine ensures that water is used responsibly and sustainably in a desert environment where scarcity is a significant concern.

Riparian rights, while a common method of water rights allocation in other states, are not applicable in Arizona. Dormant water rights refer to rights that are not actively used but remain valid, and water supply management, while important for the regulation and sustainability of water use, does not serve as a legal basis for new claims. Therefore, prior appropriation is the foundational doctrine guiding new water claims in Arizona.