A more thorough explanation:

Definition: Alluviation is the process of land boundaries gradually shifting due to the depositing of sediment and gravel by a moving body of water. The sediment deposited on the land is called alluvion. According to common law, land altered by alluviation changes any boundaries originally determined by the body of water, which can increase the owner's property. However, the owner can also lose land decreased by alluviation.

Example: A river flows through a piece of land owned by John. Over time, the river deposits sediment on the bank, which gradually extends the land. As a result, John's property increases due to alluviation. However, if the river changes course and erodes the bank, John's property can decrease due to alluviation.

The example illustrates how alluviation can affect land boundaries and property ownership. As the river deposits sediment, the land gradually expands, which can increase the owner's property. However, if the river changes course and erodes the bank, the land can decrease, which can result in a loss of property for the owner.