Noun
a fan-shaped deposit where a fast flowing stream flattens out
Source: WordNetHistory Aerial photo of Roseau The city of Roseau sits on an alluvial fan formed hundreds of years ago as the Roseau River meandered across the area from what is now known as Newtown to its current location. Source: Internet
It is platted on a quarter section of land (160 acres; 0.6 km²) on the alluvial fan of North Crestone Creek. Source: Internet
Velindre area of Port Talbot is built upon an alluvial fan deposit. Source: Internet