A
Strategic Flood Risk Assessment (SFRA) has been prepared to help us
when considering flood risk as a planning issue.
It informs decisions on planning applications and
forms part of the evidence base for the
Local
Development Framework. The information is also useful to us in
other roles, such as highway drainage and emergency management.
The SFRA is in three parts:
- a Level 1 study of North Somerset
- a Level 2 study of Clevedon, Nailsea,
Portishead and larger villages
- a Level 2 study of the Weston-super-Mare
area.
The
Level 1 study (pdf, Sep 09, 38.8MB) provides
an overview of flood risk across North Somerset (excluding Steep
Holm) and includes the breakdown of the Environment Agency’s
Flood Zone 3 into 3a and 3b (functional floodplain), which is
needed to apply the Sequential Test in
Planning Policy Statement 25: Development and Flood Risk.
The outputs from this study comprise a
written report and two sets of maps, one showing historic flooding
records and the other showing existing and future flood risk,
including the impact of climate change between now and 2108.
Existing flood risk is mapped on the basis of a
1-in-100-year return period flood level in the case of rivers
(fluvial flooding) and a 1-in-200-year return period flood level on
the coast, including the tidal length of rivers (tidal flooding).
This is known as Flood Zone 3. The extent of an extreme flood event
(up to 1-in-1000-year return period) is known as Flood Zone 2.
Flood Zone 3 is expected to expand as a result of climate change to
take in the current Flood Zone 2 and additional land.
The Environment Agency’s Flood Zones show flood
risk in the absence of flood defences. In practice, these reduce
the real risk to which people and property are exposed. It is
important though to know the extent of the theoretical floodplain
because defences can be breached or overtopped. The division
into 3a and 3b takes account of flood defences provided that they
are of a sufficient standard.
You can view the extent of the flood zones and other planning
related information by using our
Planning
Map.
To view the relevant map see the
reference key to find the appropriate reference, then select
the corresponding plan from the list below.
ST35NE, Historic
ST35NE, Existing and future
ST35NW, Historic
ST35NW, Existing and future
ST36NE, Historic
ST36NE, Existing and future
ST36NW, Historic
ST36NW, Existing and future
ST36SE, Historic
ST36SE, Existing and future
ST36SW, Historic
ST36SW, Existing and future
ST37SE, Historic
ST37SE, Existing and future
ST45NE, Historic
ST45NE, Existing and future
ST45NW, Historic
ST45NW, Existing and future
ST46NE, Historic
ST46NE, Existing and future
ST46NW, Historic
ST46NW, Existing and future
ST46SE, Historic
ST46SE, Existing and future
ST46SW, Historic
ST46SW, Existing and future
ST47NE, Historic
ST47NE, Existing and future
ST47NW, Historic
ST47NW, Existing and future
ST47SE, Historic
ST47SE, Existing and future
ST47SW, Historic
ST47SW, Existing and future
ST55NW, Historic
ST55NW, Existing and future
ST56NE, Historic
ST56NE, Existing and future
ST56NW, Historic
ST56NW, Existing and future
ST56SE, Historic
ST56SE, Existing and future
ST56SW, Historic
ST56SW, Existing and future
ST57NW, Historic
ST57NW, Existing and future
ST57SE, Historic
ST57SE, Existing and future
ST57SW, Historic
ST57SW, Existing and future
The main
Level 2 study (pdf, Jul 10, 25MB) looks in
detail at five areas of interest (the document may take some time
to download due to the file size):
-
Area 1: coastal
strip from south of Clevedon to Ham Green
-
Area 2: draft
RSS proposed urban extension area south-west of Bristol
-
Area 3: land
around Nailsea and Backwell
-
Area 4: land
around Yatton and Congresbury
-
Area 5: land
around Banwell, Winscombe, Churchill, and Wrington
Certain caveats attach to the Level 2 report as
follows:
Areas 1/2 – No further strategic growth is
planned for these areas. Any proposals for this would have to
consider the need for additional flood risk information.
Areas 3/4 – The Level 1 flood maps must be used
for Sequential Test purposes and not Figures 3.12 and 3.13. The
undefended depth/velocity information is still relevant and should
be used regarding the Sequential Test. Should additional growth be
expected for Areas 3 and 4 the flood risk evidence would need to be
revisited before identifying sites.
A separate
Level 2 study of Weston-super-Mare (pdf, Jan
11, 25MB) has also been undertaken. This covers the same
range of information that the main Level 2 study provides for
other areas but also relates it specifically to potential
development sites.
Separate files comprise Appendices B, C, D and
E. These are available to view at Somerset House on request
or a CD can be sent out.
The SFRA is a living document and the published
reports need to be read in conjunction with the latest available
information. This can arise from updates to the Environment Agency
Flood Map (dealing with the boundaries between Flood Zones 1, 2 and
3) and from local or site-specific studies that review the 3a/3b
split. Two updates have been accepted to date, for
Bleadon/ Loxton (pdf, Mar 11, 948k) and
Congresbury/ Yatton (pdf, Mar 11,
661k).
A challenge to the SFRA classification at
Colehouse Farm, Kenn (pdf, Oct 11,
2.4MB) has also been upheld, as a result of which the land
shown has been reclassified from fluvial 3b to fluvial 3a.
For more information about the
SFRA contact our
Planning
Policy team.
