A floodplain is flat or nearly flat lowland bordering a stream or river that experiences occasional or periodic flooding. Read more about it in this document, which is illustrated with many photos from the field.
CRWP (n.y): Floodplain Restoration and Storm Water Management: Guidance and Case Study. Willoughby: Chagrin River Watershed Partners (CRWP), Inc. URL [Accessed: 09.05.2019]