accretion—A gradual and imperceptible build-up of land by natural means. This accumulation of land can be either by the recession of the sea or a river, thus exposing land, or by the deposit of sand or soil washed up from water to form firm ground. When there is a recession of the water, the term applied is “reliction.” Where, due to natural causes, land forms on the bank of a body of water, the term applied is “accretion.” Accretion of land is of two kinds: By alluvion, i.e., by the washing up of sand or soil, so as to form firm ground; or by dereliction, as when the sea shrinks below the usual watermark. The term “alluvion” is applied to the deposit itself, while “accretion” denotes the act. However, the terms are frequently used synonymously. In determining whether the change in the course of a river is by “accretion” or “avulsion,” the test is not whether witnesses might see from time to time that progress has been made, but whether witnesses could perceive the change while it was going on. See also dereliction; reliction; recession of water.

accretion topography—Topographic features built by accumulation of sediment, especially meander scrolls.

–

Source: NSPS “Definitions of Surveying and Associated Terms“, used with permission.

Part of LearnCST’s exam text bundle.