floodplain
/ˈfləʊdpleɪn/Definitions
1. noun
A low-lying area of land adjacent to a river that is subject to flooding, especially after heavy rainfall or a storm.
“The city’s floodplain was severely affected by the recent hurricane, causing widespread damage and displacement.”
2. verb
To cover or overflow with water, typically as a result of heavy rainfall or a storm surge.
“The storm surge flooded the coastal town, forcing residents to evacuate the area.”