alluvion

noun | \ ə-ˈlü-vē-ən \ | al·lu·vi·on

1. : material (as clay, silt, sand, or gravel) deposited by running water; especially : the land added by the gradual or imperceptible accumulation of such material along a bank or shore alluvion formed in front of the property of several owners is divided equitably —Louisiana Civil Code : the land added by the gradual or imperceptible accumulation of such material along a bank or shore alluvion formed in front of the property of several owners is divided equitably —Louisiana Civil Code