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coast at Walton is made up of two contrasting areas. One area is
protected coastline, the other unprotected. The protected area of
coastline, at the southern end of the large spit called the Naze,
has large wooden or metal groynes.
These are there to prevent erosion. Longshore drift brings sediment
northwards along the shore and this piles up on the southern side of
the groynes, widening the beach and so limiting erosion of the
cliffs behind. Schemes like this have required large council
investment.
Other, different
methods to prevent erosion at the southern end of the Naze
have been employed. On top of the cliff area we saw a lot of
vegetation. This was planted to encourage rainwater to infiltrate
into the ground rather than running over the surface of the cliffs
and eroding them. Large concrete steps have also been installed just
behind the beach, before the slope of the cliff. These are there to
slow down the speed of the waves and to protect the bottom of the
cliffs. There are also pipes within the cliffs leading to small
holes in the concrete steps that allow rainwater to drain out onto
the beach.
As you
move further north along the coast the cliffs
become steeper and there are more landslides. Part of the area of
the cliff is protected with rip rap.
These are large boulders or stones used to slow the waves down to
stop erosion. Only this part of the cliff is protected because there
is a footpath up to the top of the cliff.
The rest
of the cliff is left unprotected and you can see the difference. The
cliff is made up of London Clay and Red Crag. The Crag is at the top
and is permeable. The London Clay beneath is impermeable. The cliff
is already very eroded. There is a Second World War pill
box that was built on the top of the cliff fifty years ago
but which is now on the beach. As the cliff has retreated back, the
pill box was undermined and slumped slowly down on the beach. You
can see it as the sea washes over it at high tide. When the tide is
out, you can walk along the beach and find fossils from both the
London Clay and the Red Crag. In the London clay there are fossils
such as twigs, nuts and sharks teeth. This is because, some fifty
million years ago, Walton-on-the-Naze was part of huge river. When
the river met the sea, the twigs and other objects were deposited
and they began to decay. As the years went by they sank further and
further into the mud and were turned into a hard mineral. Now, when
waves break against the base of the cliffs, they washes the fossils
out of the clay, making them easy to see on the wave-cut platform.
The
fossils in the Red Crag are younger and came about one million years
ago. The sea swept over the London Clay, bringing shells and stones.
They can be found on the shore after the sea has eroded the bottom
of the cliff and the rock above as fallen down as landslides. The
most common fossils found in the Red Crag are Natica, Scallop,
Glycymeris, Turrettella and Neptuna. They are often stained orange
from the clay.
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Towards the end of
June, the entire Second Year (Year 8) were taken for a day to
Walton-on-the-Naze in Essex. The aims of the visit included studying the
ways the local North Sea coastline is protected as well as comparing
characteristics of the town of Walton with Radlett, a settlement of
similar size close to the school in Hertfordshire. Tide patterns
permitting, there was also the opportunity to hunt for fossils on the
beach below the cliffs near the Naze, and no day to the seaside would be
complete without a visit to the pier, where staff and students did battle
on the dodgems.