* Describing soil: "The fertile alluvial soil of the Nile River Valley has supported agriculture for centuries."
* Describing landforms: "The alluvial plain stretched out before them, a flat expanse of land formed by the deposited sediment of a river."
* Describing a geological process: "The alluvial process of erosion and deposition shapes the landscape over time."
* Describing a specific location: "The ancient city was built on an alluvial fan, where the river once flowed."
Remember, "alluvial" refers to things related to the deposition of sediment by a river or stream.