Definition from Wiktionary, the free dictionary
floodwall (plural floodwalls)
- A man-made vertical barrier designed to temporarily contain the waters of a river or other waterway during a flood
2007 May 29, John Schwartz, “Can Science Outwit Storms Like Katrina?”, New York Times:
- The New Orleans levees and floodwalls were built to withstand a hypothetical storm […] .