a concrete structure, maybe two feet wide at the visible base, with an inverted T- or L-shaped underground base for stability

A vertical concrete levee usually built along roadsides and around neighborhoods where there is not space for the massive side slopes of an earthen levee.

A long, narrow concrete, or masonry embankment usually built to protect land from flooding. If built of earth the structure is usually referred to as a levee. Floodwalls and levees confine streamflow within a specified area to prevent flooding. The term "dike" is used to describe an embankment that blocks an area on a reservoir or lake rim that is lower than the top of the dam.

a self-supporting barrier to floodwater

A wall constructed adjoining channel to prevent flooding of the surroundings areas.