Geography Reference
In-Depth Information
GAUGING THE URBAN FLOOD
HAZARD IN MANCHESTER, UK
(see Figure 7.3). However, there is no recent
history of significant flooding, and the residents
and industrialists using the floodplain are generally
very unaware of the risks that they face. As a
consequence, and supporting the hazard-response
model, there is very little attempt by the people at
risk to protect themselves against future flooding.
Many of the industrial properties are occupied by
ephemeral 'ethnic' clothing manufacturing
businesses, thus exacerbating the general ignorance
of flooding problems in the area.
Flooding mechanisms and impacts
The River Irwell rises in the hills above Bolton in
Lancashire, UK, and flows southwestwards into the
Mersey and the Irish Sea.
The flood-generating mechanism is frontal rain
on these hills from Atlantic winter depressions. The
effect is flooding downstream in the Salford area
of Greater Manchester (Figure 7.4). This flooding
has been exacerbated because, first, the channel of
the river was moved fifty years ago to allow for
urban and industrial development, and second,
because the river is now 'hemmed in' by low
embankments to maximise the usable area of
valuable land in a congested urban location. Some
out-of-bank flooding nevertheless occurs at return
periods as low as five years.
The area has experienced some severe flooding
in the past, notably in 1866, 1946, 1954 and 1980
Damage potential
A survey has gauged the likely damage that would
occur were the properties on the flood-plain to
be flooded from flood severities up to and
including the 250-year event. This survey was
designed to assess the benefits of providing a range
of flood protection measures, including major
engineering works to the river and its floodplain,
within a framework of investment appraisal that
Figure 7.4
Flooding and flood
hazard solutions for the River
Irwell, Manchester, UK.
