Transcript Floods Hard and Soft Engineering

Floods
Hard Engineering
Hard Engineering
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This uses technology, large amounts of
money to try and control the river.
It can prevent floods in the short term.
In the long term the river will try to get out of
this ‘straight jacket’ and the floods can be
made worse as a result.
Dams
Straightening (or channel realignment
Meanders are removed
from a river, this means
the water has less distance
to travel and can therefore
be removed quicker.
However, it increases
erosion and flooding
downstream. Straightening
increases the rivers
efficiencey.
Diversion Spillways
( includes intercepting channels and flood
relief channels)
Floods are directed
away from housing
and settlements into
extra land or
channels. However in
urban area this isn't
possible, and
compensation often
has to be paid to
those who own the
land.
Flood wall
Building up of levees
(embankments, flood walls, artificially
enhanced levees, revetments)
The levees are widened and
heightened to increase the
amount of water a river can
carry before it floods. They are
often enforced with concrete.
Flood magnitude may
increases due to the increased
amount of water held.
Increased flooding upstream
and downstream, and
increased erosion downstream.
Straightening or
Realigning
Channelisation
Containment
The Dijle Case Study