n. the low-lying land adjacent to a river, usually of rich soil because of alluvial deposits left by spring freshets.
See also: interval
- 1912  Raven is just ahead in the woods there alone and the Indian is further back with a bunch of ponies down in the riverbottom.
- 1963  He may also be reworking bars or sections of riverbottom which are only exposed at low water or taking up bedrock which has been made workable by recent weathering.