Alluvio

Alluvio is thus defined by Gaius (Inst. 2.701): Alluvium is an addition of soil to land by a river, so gradual that it is impossible to estimate how much is added in a short period, or, as it is commonly expressed, the charge is so gradual as to be imperceptible. But a piece of your land swept away by a river and carried down to mine continues your property. There is the same definition by Gaius in his res cottidianae (Dig. 41, 1, 7), with this addition: If the piece of land thus suddenly swept away should adhere for a considerable time to my land, and the trees on it should fix their roots in my soil, it thereupon becomes my property. Alluvio was considered by the Roman jurists as a mode of acquiring property in a thing, which belongs to the jus gentium or naturale; it was a particular kind of title by accessio. A man might protect his land against loss from the action of a river by securing the banks of his land (Dig. 43, 15, de ripa munienda), provided he did not injure the navigation.

An island that was formed in the middle of a river was the common property of the owners on both banks of the river; if it was not in the middle of the stream, it belonged to the proprietors of the nearer bank (Gaius, 2.72; Dig. 41, 1, 7). By a river is meant a public river (flumen publicum). According to a constitution of the Emperor Antoninus Pius, there was no jus alluvionis in the case of agri limitati, the reason being that a certain quantity (certus cuique modus) was assigned by the form of the centuriae (Dig. 41, 1, 16; comp. Aggenus urbicus in Frontin. Comment. de Alluvione, pars prior, ed. Goes; and Ager). Cicero (Cic. de Orat. 1.38) enumerates the jura alluvionum and circumluvionum as matters included under the head of causae centumvirales (Hermannseder, die Alluvien, München, 1856).

[G.L] [E.A.W]