Jane Nower -
15-Nov-2007 - The Environment Agency signed up local radio
107.8 Radio Jackie this week, as an official media ‘flood
warning’ partner. When the Environment Agency is expecting
weather conditions to lead to flooding it issues a series
of alerts known as flood watches and flood warnings directly
to the public by text, phone, fax or email, as well as
via local media.
As Radio Jackie broadcasts to a wide
range of listeners, reaching homes and businesses from
Isleworth in the London Borough of Hounslow down to Banstead
in Surrey, it is hoped that the Environment Agency’s messages
will be heard far and wide.
In each region managed by the Environment
Agency, teams of staff plan the way that the area should
respond to flooding, both from the point of view of preparing
for and reacting to events. Forecasting for the rivers
in the south east of the Thames region takes place in
Reading at the Environment Agency’s Flood Forecasting
Centre, where an extensive network of rain and river gauges
are monitored and a variety of forecasting techniques
are used to predict what is expected to happen.
If rivers are forecast to come out of
banks or flood properties, Flood Watches or Warnings are
issued by the Thames South East Area Flood Incident Management
team.
Louise Guy, a flood incident technical
specialist for the south east of the Thames region said:
“Within the Radio Jackie catchment, five different rivers
and their tributaries all flow northwards towards the
Thames, and each one reacts to changing weather in a very
different way. In the south east, the Beverley Brook and
Hogsmill rivers respond quickly to rainfall as they act
as a drain for highly urbanised areas where rainfall runs
off immediately into the rivers, rather than soaking into
the ground.
“However, the Wey, Bournes and Mole
rivers tend to respond much more slowly than the Beverley
Brook and the Hogsmill. It generally takes sustained rainfall
with high totals to cause these rivers, and the Thames
itself to rise to levels where properties are flooded.”
Eamonn Forde, who manages flood risk
in the tidal Thames area of the Radio Jackie catchment
added: “The River Thames itself is defended to a very
high standard and the Thames Barrier and its associated
gates are part of these defences. When there is a significantly
high tide combined with a surge in water levels coming
up the Thames estuary, we close the Thames Barrier to
protect central London.
“The Barrier has no individual trigger
level for closure. Hydrological and meteorological data
from the Met Office is fed to our control room by telemetry
and is used in our own forecasting models. The decision
to close is based on three major factors: the height of
the tide in the Thames estuary, the tidal surge, which
naturally accompanies each tide and the flow entering
the tidal Thames, which is measured as it passes over
Teddington weir. Closure of all ten gates takes just under
one and a half hours. The gates then remain closed until
the water level downstream of the Thames Barrier has reduced
to the same level as upstream.”
Lucy Mayer, a news broadcaster for Radio
Jackie said: “This media partnership with the Environment
Agency will mean that we are able to provide up-to-the-minute
information about flooding, as well as getting a much
better idea of the challenges that face our listeners
at home and at work as they learn to deal with flooding.”
The Environment Agency is encouraging
as many people as possible to sign up to Floodline on
0845 988 1188 to protect their homes and businesses from
flooding.
