What type of water rights may be described as "first in time, first in right"?

The term "first in time, first in right" refers specifically to appropriative water rights. This principle is a fundamental aspect of water law in the context of scarce water resources. Under appropriative rights, water is allocated based on the sequence of use — the first person to divert and use water has priority over those who come after them. This means that if a drought or shortage occurs, those who established their rights to the water first will have the legal claim to use it before others.

Appropriative rights contrast with littoral and riparian rights, which are associated with land ownership adjacent to a body of water. Littoral rights pertain to properties bordering large bodies of water (like lakes) and focus on the landowner's right to access and use the water. Riparian rights apply to landowners whose property abuts a flowing water source (like rivers), granting them rights to use the water, but these rights do not follow the priority system of time and usage that characterizes appropriative rights.

Principal is not a commonly recognized type of water rights, making it irrelevant in this context. Thus, the structure and historical context of appropriative water rights make them the correct choice in this scenario, showcasing the importance of timing in legal claims to