What does alluvion refer to?

Alluvion specifically refers to land that is formed gradually as a result of natural sediment deposition caused by flowing water, typically along rivers or near coastal areas. This process leads to the accumulation of soil and minerals, which over time creates new land. It is a geological phenomenon crucial to understanding property and land rights, especially in the context of riparian law, where land adjacent to water bodies can expand or contract based on natural deposition or erosion.

The other options touch on different aspects of land and property rights but do not accurately define alluvion. For example, measuring land ownership is a legal and surveying practice rather than a natural occurrence, ownership rights to underwater land might relate more to navigable waters or mineral rights, and government-owned land deals with a different aspect of land management and governance. Thus, identifying alluvion strictly as land formed through natural processes aligns with established definitions in both legal and environmental contexts.