What is the term for the process in which land area increases due to water depositing soil?

The process in which land area increases due to the deposition of soil by water is known as accretion. This geological phenomenon occurs when sediment, such as soil or sand, is carried by moving water and accumulated in areas where the water slows down, such as riverbanks or shorelines. Over time, this accumulation leads to an increase in land mass.

In contrast, erosion refers to the process of soil and rock being removed from one location and transported to another, often resulting in a loss of land. Degradation typically describes the decline in the quality of land or soil, often due to human activities or environmental factors. Deterioration highlights a reduction in condition or quality, which is also not related to the constructive process of land growth through sediment deposition. Thus, accretion is the appropriate term for the process described in the question.