Transcript Management of coastal recession at Walton-on

Management of coastal recession at
Walton-on-the-Naze
(Case Study)
• Walton-on-the-Naze is a coastal town in Essex. It suffers
from coastal erosion due to the types of rock which make
up the cliff.
• The rock types are London Clay and Red Crag and both of
these rock types are easily eroded by the sea.
• The cliffs also suffer from slumping which makes the
defence of the area even more complex.
• Longshore drift moves sand along the coastline from
south to north.
• All of these factors must be considered when deciding
the type of management that will be effective in an area.
• Walton can be split into two distinct areas. The
northern end of the coastline has not been protected
because the Environment Agency does not consider the
buildings there worth saving.
• The only buildings there are a Grade II listed Tower and
several houses on Old Hall Lane.
• The southern part of the coastline has been protected
because of the coastal town of Walton with its
population of 12,000.
• In 1977 a major project was completed on the southern part of the
coastline.
• It consisted of a seawall, breakwaters and groynes. This was to
protect the properties on the cliff such as Sunny Point road where the
average house price is £400,000.
• It must be
considered
why these
particular
techniques
were used
at Walton?
• Groynes were used because longshore drift was occurring along
the coastline from the south to the north. The groynes would
help to stop longshore drift and keep the beach in place.
Breakwaters, which are large groynes, were also placed at
regular intervals because of the power of the longshore drift on
this particular coastline.
• The cliff was regraded to produce a gentler slope and drainage
channels were installed to allow water to flow underground
through special tunnels and out onto the beach through holes in the
seawall.
• The regraded cliff was planted with a variety of shrubs and trees
which included gorse and nettles at the side of the path to stop
people from scrambling on the cliff.
• At the bottom of
the cliff there is a
seawall - this is to
protect the London
clay there which
is very easily eroded
by the sea.
• In 1998 the council paid £167,000 for 300 tonnes of granite to
be placed around the Tower breakwater.
• This rip-rap has slowed down erosion in this area but has not
stopped it. The beach in front of the cliffs at the northern part
of the coastline was replenished in 1999 with sand and gravel
which had been dredged from Harwich Harbour.
• However, the majority
of this material had
been removed by
2003 illustrating the
power of longshore
drift along this
stretch of coastline.
Today’s Activity
• Complete the worksheet.
• You only have until the end of this lesson.
• Stick in the worksheet.
• If you finish, read through your exercise
book/textbook as revision for the test.
Swanage
2005
Swanage
2006