Because they do
Levees are built along the banks of rivers
Natural levees are built up over time from debris and sediment whereas artificial levees are man made using sand bags and larger rocks.
A levee is a natutral or artificial embankment built along a rivercourse, or an arm of the sea, to protect adjoining land
levees
A traditional flood control method used to keep a stream's flow in its channel is the construction of artificial levees. These raised embankments are built alongside rivers or streams to prevent overflow during heavy rainfall or flooding. By confining the water within the levees, they help direct the flow and protect surrounding areas from flood damage. Other methods, such as dams, can also regulate water flow, but levees specifically aim to contain riverbanks.
Levees, dikes.
Levees are structures built along rivers or coastlines to prevent flooding by containing the water within a designated area. They help protect communities by reducing the risk of water overflowing and causing damage to homes, businesses, and infrastructure.
The embankments are called levees. When the levees around New Orleans failed during and after Hurricane Katrina it led to catastrophic flooding. Note that money had been allocated for work on the levees prior to that but it was decided to use it to improve the roads on top of the levees which, technically, was an "improvement" but one wonders how it would have all played out if it had instead been used to improve the strength of those those levees prior to Katrina.
A wall of earth built to keep out water is called a levee. Levees are commonly built along rivers, lakes, or coastlines to prevent flooding by reinforcing natural barriers with man-made structures.
..... stop floods, just like the levees on the Mississippi.
levees or banks
Levees are embankments or walls built along rivers or coastlines to prevent flooding by containing water within a designated area. They work by raising the height of the natural shoreline, effectively creating a barrier that redirects floodwaters away from populated areas. Levees must be properly engineered and maintained to ensure they can withstand the pressure of floodwaters and remain effective at protecting against flooding.