Accretion is the gradual and imperceptible addition of soil by gradual deposition through the operation of natural causes, to that already in possession of the owner. It is the gradual instrusion of the dry land area into the water area. Accretion is formed by the washing up of sand, silt or soil so as to form firm ground, called alluvion. Reliction is dry land formed by the withdrawal of water from the shores of a river, lake or sea. The process of the water withdrawal is termed dereliction.
Erosion is the direct opposite of accretion.
It is the gradual eating or gnawing away of soil by the operation of water, so that the water encroaches upon an area that was dry land prior to the erosion. Avulsion is the sudden and perceptible action of water which causes the removal of a considerable quantity of soil from the land of one owner and its deposit upon or annexation to the dry land of another. This may be sudden or rapid change in the course and channel of a river or the sudden creation of a completely new channel. It is distinguished from accretion and erosion by the time element. Historical Development From the earliest of times in England, the common law vested title to and control over navigable waters in the Crown and in the Parliament.