Meaning of ACCRETION in English
The imperceptible and gradual addition to land by the slow action of water. Heavy rain, river or ocean action would have this effect by either washing up sand or soil or by a permanent retreat of the high water mark. The washing up of soil is often called avulsion although the latter term is but a variety of accretion.
Duhaime's Law English dictionary. Английский юридический словарь Duhaime . 2012