George the Geographer’s guide to coastal
management at Walton-on-the-Naze
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Naze Tower
Geology
Cliff profile
measurements
Management
survey
Longshore
drift
Management
Old
pictures
Cause of
erosion
Beach
profile
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Geology
Home
Geology
Cause of
erosion
Longshore
Drift
The cliffs all the way along the coast at Walton-on-the-Naze rest on
London Clay. On top of this are a number of other deposits. By the
Naze Tower the cliffs are level and rise about 20 metres above the
beach. Further north, the cliffs decrease in height, over a distance
of 300 metres, to just 4 metres above the level of the beach. Over
the next 220 metres they gradually decrease to the flood wall.
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
The different rock types
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Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
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Naze Tower
Management
Brickearth
This is a layer of clayey loam. it is thicker at
the northern end where it lies directly on top
of the London Clay.
Pleistocene Beds
These are made up of gravels, clayey
sands and thin, grey clays. These beds are
missing along the lower cliffs to the north.
Red Crag Beds
This is a red-brown, sandy, shelly layer.
This bed is rich in fossils and was
deposited when the area was covered in
warm seas. these deposits are the only
ones of this age known in Britain. the
combination of shells found in this bed is
unique. One fossil is 'Neptunia Contrarius',
a whelk which is unusual because its shell
spirals 'anti-clockwise' and opens on the
left, whilst most modern ones spiral the
other way round.
London Clay
This is a sticky, grey, impermeable clay
which was formed around 60 million years
ago. the top layer is very contorted. the
rock contains many fossilised shark teeth
and plants.
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
The Cause of Erosion
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Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
The are a number of reasons to explain
the erosion at Walton-on-the-Naze.
Firstly, at high tide, the sea reaches the
base of the cliffs. The processes of
erosion attack the London Clay making
the foot of the cliff steep and unstable.
When it rains, the water soaks into the
sand and gravel layers. From here it
percolates downwards through the sand
and gravels and the Red Crag beds.
It will keep moving downwards until it
comes to the London Clay. This is
impermeable so the water can not pass
through it. Instead it collects on top of the
London Clay and acts like a lubricant,
making the surface more slippery. This,
combined with the increased weight of the
wet, saturated rock makes the whole cliff
unstable.
(continued on next slide)
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
The Cause of Erosion (continued)
Home
Geology
Cause of
erosion
The London Clay can not support the
weight of the cliff above it and the cliff
begins to slump. As it does so, it pushes
rock and debris onto the beach where it is
eroded and removed by the action of the
sea. Once it is removed the sea can
attack the base of the cliff and the
process starts over again.
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Whilst this is happening, water drains out
of the rock above the London Clay. As it
flows over the cliff face it saturates the
rock that has fallen which helps make it
slide and slump onto the beach.
(continued on next slide)
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
The Cause of Erosion (continued)
Home
As the erosion occurs it looks like a series of ‘bite shapes’ have been taken out
of the cliff foot.
Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Longshore Drift
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Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Longshore drift can be investigated in two ways.
After a minute the
distance the float has
travelled is measured.
Drop a float (such as an orange) into
the waves and see how far it travels
The direction it travelled
is also noted.
Minute 1 – 4.2 metres
Minute 2 – 5.0 metres
Minute 3 – 5.1 metres
The float travelled from
south to north.
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Longshore Drift (continued)
Home
Geology
Cause of
erosion
Measure
fromdrift
the top
groyne to in
thetwo
level
of the beach to see if the beach has built up
Longshore
canof
beeach
investigated
ways.
on one side of the groyne. The side with the shortest measurement means the beach material
has built up on that side.
If there is more sediment on the north side, longshore drift is going from north to south. If
there is more on the south side, longshore drift is moving from south to north.
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Some results on
the next slide
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Longshore Drift (continued)
North
South
Low tide measurement
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Geology
Cause of
erosion
Mid tide measurement
High tide measurement
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Beach profiles
Unprotected cliffs north of the Naze Tower
Home
Geology
Cause of
erosion
Longshore
Drift
A clinometer is used to
measure the angle of the
beach starting at the sea
and working towards the
sea wall or foot of the cliff
Distance from the sea (m)
Angle (degrees)
0 - 19
1
19 - 28
0
28 - 37
1
37 - 41
2
41 - 63
3
63 - 72
4
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Protected cliffs south of the Naze Tower
0-7
2
7 - 23
4
23 - 44
5
44 - 56
6
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Cliff profiles
Home
Geology
Cause of
erosion
Longshore
Drift
Beach profile
In the past it was possible to measure the angle of slope
of the cliff. By each groyne, a 30m tape was laid up the
cliff face starting at the foot of the cliff. A measurement
was taken every time there was a major change in the
angle. A minus sign shows a downwards slope.
With more vegetation plus health and safety, it is not
possible to measure the cliff face the same way today
South
Cliff profiles of protected cliffs 1984
Groyne 6
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Groyne 5
Groyne 4
Groyne 3
North
Groyne 1
Tower Breakwater
Groyne 2
Distance
from sea
wall (m)
Angle
(degrees)
Distance
from sea
wall (m)
Angle
(degrees)
Distance
from sea
wall (m)
Angle
(degrees)
Distance
from sea
wall (m)
Angle
(degrees)
Distance
from sea
wall (m)
Angle
(degrees)
Distance
from sea
wall (m)
Angle
(degrees)
0 - 33
5
0 - 17
5
0 - 13
6
0 - 12
6
0 - 54
10
0 - 23
7
33 - 58
16
17 - 38
15
13 - 55
15
12 - 45
14
54 - 61
-2
23 - 51
15
58 - 68
-2
38 - 56
16
55 - 63
1
45 - 59
-2
61 - 78
31
51 - 58
1
68 - 79
20
56 - 64
1
63 - 78
31
59 - 77
29
Top of cliff
Level
58 - 63
15
Top of cliff
Level
64 - 76
32
Top of cliff
Level
Top of cliff
Level
63 - 76
33
Top of cliff
Level
Top of cliff
Level
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Cliff profiles
Home
The protected cliffs were measured at one point a few years later
in the 1990s
Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
IDEA!!
You could use the information to draw the shape
of the cliffs. If it looks similar to the present day
shape, it could help tell you if the management
scheme has worked.
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Cliff profiles
Home
Geology
Cause of
erosion
These are the
measurements of the
sea wall at the base of
the protected cliff
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Cliff profiles (unprotected cliffs before Crag Walk constructed)
Level with Naze Tower (1978)
Home
Geology
Cause of
erosion
Longshore
Drift
Beach profile
These are the
measurements of the
unprotected cliff.
They were taken in
1978 and 1984.
Steep slopes with lots
of changes in gradient
would show that the
cliff is slumping and
eroding.
Angle
(degrees)
Distance from cliff
foot (m)
Angle
(degrees)
Distance from cliff
foot (m)
Angle
(degrees)
0 - 1.6
53
0-2
36
0 - 1.5
72
1.6 - 8
4
2 - 14
7
1.5 - 20
4
8 - 24
31
14 - 29
37
20 - 24
89
24 - 46
13
29 - 33
-13
24 - 30
3
46 - 51
-5
33 - 39
26
30 - 33
90
51 - 62
10
39 - 46
13
Top of cliff
Level
62 - 68.5
88
46 - 51
39
Top of cliff
Level
51 - 54
90
Top of cliff
Level
Level with Naze Tower (1984)
Management
Survey results
Naze Tower
Management
375 metres north of Naze Tower
(1978)
Distance from cliff
foot (m)
Cliff profile
measurements
Old pictures
150 metres north of Naze Tower
(1978)
150 metres north of Naze Tower
(1984)
375 metres north of Naze Tower
(1984)
Distance from cliff
foot (m)
Angle
(degrees)
Distance from cliff
foot (m)
Angle
(degrees)
Distance from cliff
foot (m)
Angle
(degrees)
0 - 51
12
0-9
48
0-1
90
51 - 58
15
9 - 14
45
1-7
51
58 - 67
72
14 - 23
4
7-9
90
Top of cliff
Level
23 - 36
60
9 - 32
1
Top of cliff
Level
Top of cliff
Level
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
How have the cliffs changed? Protected cliffs
Home
Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
How have the cliffs changed? Protected cliffs
Home
Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
How have the cliffs changed?
Home
Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
What do people think?
Home
How far have you
travelled to get to
Walton?
Live in Walton
49
Less than 5 miles
21
Between 5 - 15
19
Over 15 miles
11
What is the main purpose Shopping
of your visit?
Use the beach
33
Geology
Cause of
erosion
Work
25
Visiting family or friends
13
Open space north of the Tower
36
Close to the pier
29
By the Naze Tower
28
Don’t know
7
Are you aware of the
erosion at the Naze
cliffs?
Yes
85
No
15
Do you think the Naze
cliffs should be
protected?
Yes
71
No
27
Don’t know
8
Longshore
Drift
Beach profile
Which part of the Walton
coast do you prefer to
visit?
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
29
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
What do people think?
Home
Geology
Cause of
erosion
Do you think the high
Yes
cost of protection works
no
is money well spent?
80
Which of the following
Public open space (café and
do you think is the most picnic are by the Tower)
important to protect?
Naze Tower
40
Longshore
Drift
Beach profile
What management
would you prefer to see
used?
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Who should pay for
management works?
20
27
Houses
20
Water company works
13
Groynes and breakwater
38
Sea wall
29
Rock revetment
20
Drainage
13
Government
48
Lottery
30
Local authority
11
County council
8
Residents
3
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
What do people think?
Home
Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
The Naze Tower
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Geology
Cause of
erosion
Longshore
Drift
Beach profile
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measurements
Old pictures
Management
Survey results
Naze Tower
Management
The Naze Tower was built in 1720 by Trinity House. It
was a navigation aid and, combined with the tower at
Walton Hall, it helped vessels in the area. It is 26 metres
high and has 111 steps to a modern day viewing platform
at the top. Originally there was a beacon lit at the top so
it provided an early form of lighthouse.
In the 1700s, the tower was also a tea house. During the
Napoleonic Wars and the First World War it was used as
a lookout post. In the Second World War it was used as
a radar station with a radar dish fixed on the top.
The importance of the building was recognised in 1984
when it was given Grade II* listed status by English
Heritage. It is thought to be the only building of its kind
in existence.
The building was on the ‘Building at risk’ list until it was
renovated and opened to the public. It now contains a
tea room as well as a museum and gallery. Views of the
Naze can be seen from the public viewing gallery on the
roof.
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Management
Home
Geology
In 1977, large defence work was constructed south of the Naze Tower. The
cliffs were regarded to a stable angle. A sea wall was built to protect the cliff
foot. Drainage was added to remove water from the cliff. Concrete footpaths
and steps built. Groynes and a new Tower Breakwater were added.
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Management
Home
Geology
Cause of
erosion
By the 1990s the sea had eroded the
unprotected cliffs and there was a risk it
would erode behind the sea wall.
1998, 300 tonnes of granite rock armour was
placed at the northern end of the defence
scheme. Cost £167,000.
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Management
Home
Geology
Cause of
erosion
Longshore
Drift
In 2011, 16,000 tonnes of granite rock
armour was placed at the foot of the cliff
nearest to the Tower to construct Crag
Walk. The 110 metres of rock armour
protects the base of the cliff but also
allows people to walk on it even when
the tide is in. Information boards have
been placed at points along it. It cost
£1.2 million.
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
Continued on
next slide
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George the Geographer’s guide to coastal management at Walton-on-the-Naze
Management
Home
Geology
Cause of
erosion
The cliff will slump down to fill the space behind Crag Walk.
This means the top of the cliff will still retreat. It may save
the Naze Tower, but the café will probably be lost. Although
the cliff top will retreat, it should be at a slower rate that if
the cliff was unprotected.
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
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Home
Geology
Cause of
erosion
Longshore
Drift
Beach profile
Cliff profile
measurements
Old pictures
Management
Survey results
Naze Tower
Management
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