Slides in this set
Flood management strategies
These methods all reduce flooding however they all speed up the water downstream
and create other problems elsewhere
·Vertical barrier designed to temporarily contain
the waters of a river or other waterway which may
rise to unusual levels during seasonal or extreme
·In September 2005, following Hurricane Katrina,
New Orleans, Louisiana, was substantially
flooded after its system of levees and flood walls
failed due to soil conditions and poor design.
· They can restrict access to the river side and A floodwall gate at Harlan, Kentucky
offer little flood water storage capacity. Also they temporarily opening for train passage.
are very expensive to build and maintain.…read more
· Are often made of earth with rubble fill and more
common outside the town centre where there is
more room. If set back from the channel, they can
provide storage for excess floodwaters while
inhabited areas remain unaffected.
· Commonly used to carry a road, railway, or canal
across a low-lying or wet area
· They take up large amounts of room so are not
commonly situated in cities.
· Embankments should be constructed using
suitable materials to provide adequate support to
the formation and long-term stability. West Somerset Mineral Railway
embankment near Gupworthy,
· If the wrong materials are used the embankment UK
will not last for a long period of time.…read more
·A raised bank of alluvium flanking a river. The
bank is built up when the river dumps much of its
load during flooding.
·May be artificially enhanced or introduced to
raise the level of the river bank. This is done to
regulate the water levels.
·The main purpose of a levee is to prevent
flooding of the adjoining countryside; however,
they also confine the flow of the river, resulting in
higher and faster water flow.
· The area behind the levee is typically poorly drained since the water cannot flow up the levee
into this area.
A levee can breach and break away leaving a large opening for flood water to flood the protected
land. Water can also go over the top of the levee. This can lead to landslide erosion of the
· These methods attempt to restrict floods either by creating a smoother channel for faster flow to
get the water out of the area as quickly as possible or by widening/deepening the channel.
· It is often achieved by lining the channel with concrete and the latter by dredging to increase
the capacity. Both schemes may increase the risk of flooding downstream and both require
maintenance as the channel reverts back to a more natural state by a combination of deposition
and erosion.…read more
· Constructed to redirect excess water upstream of a settlement via an alternative route. Water
is able to re-enter the main channel further downstream, thereby reducing the flood risk.
· By creating a bypass that can only be accessed at high discharge levels, the peak flow in the
main channel is reduced. The relief channel may remain dry until activated by floodwaters.…read more