A flood embankment is traditionally an earth wall used to shore up flood waters.
Most flood embankments are between 1 metre and 3 metres high. A flood embankment is rare.
Modern improvements to this design include constructing an internal central core made from impermeable substance like clay or concrete, some even use metal pilings.
Some authorities call man-made structures levees.
Problems +Animation of types of floodwall failuresOvertopping some flood embankments are designed to overtop
example Clifton, Rawcliffe and Poppleton IngsWhen not by design, the crest can wash away and cause a breachStructural failure If any weakness is detected under strong water pressure, the compromise
is soon exacerbated Rotation
When the structure has moved of its axis causing an exposed area to be washed awaySliding When the structure has moved sideways exposing the foundation to erosion
as well as allowing gaps in between the structuresSeepage When water infiltrates under the structure. This is caused by burrowing animals
like dogs, beavers, badgers and ottersPiping When water finds its way under the structure and collects on the other side.
A central core is normally designed in to prevent piping The main problem is the space required to construct and maintain such a structure.
A flood embankment of 2.5 metres high requires an outreach of 15 metres, which makes it unsuitable in some areas.
To prevent seepage through the embankment a central core is added to acquire stability and integrity.
Examples
Clifton, Rawcliffe, Poppleton and Leeman ings in York
River Gowan, Cumbria
River Trent
Animation
This is an animation showing a flood event overwhelming neighbouring properties and the added construction of a flood embankment and flood warning and protection statuses.
References