名詞 alluvion:

1. gradual formation of new land, by recession of the sea or deposit of sediment
2. the rising of a body of water and its overflowing onto normally dry land
   同義詞：flood, inundation, deluge
3. clay or silt or gravel carried by rushing streams and deposited where the stream slows down
   同義詞：alluvial sediment, alluvial deposit, alluvium