Assessment of the Movement of Material Along Deal's Beach
This was carried out at site 3 because there are groynes at site 3
which created an area within 2 groynes called a groyne box which I
could study in order to look at the movement of pebbles within a
confined area.
Diagram of a Groyne Box:
Sea Wall
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1 2
3
4 5
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Groyne 1
Groyne 2
Sea
The purpose of this aim is to see the effects of Longshore Drift over
a longer period of time.
Theory Work
Groynes are structures that extend finger like, perpendicularly from
the shore. Usually constructed in groups called groin fields, their
primary purpose is to trap and retain sand, nourishing the beach
compartments between them. Groynes initially interrupt the longshore
transport of littoral drift. They are most effective where longshore
transport is predominantly in one direction, and where their action
will not cause unacceptable erosion of the down drift shore. When a
well designed groin field fills to capacity with sand, longshore
transport continues at about the same rate as before the groins were
built, and a stable beach is maintained.
Groynes are suitable erosion control measures where a beach is
desirable, and they are compatible with most recreational activities.
The beach fed by the sand trapped between the groins acts as a buffer
between the incoming waves and the backshore and inland areas: the
waves break on the beach and expend most of their energy there. Filled
groins provide this protection during normal weather conditions but
offer only limited protection against storm-driven waves. Groynes can
be found a t Deal.
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Seawalls are solid structures built parallel to the beach for two main
reasons. One reason for building seawalls is to protect homes on the
coastline from the destruction of large storms such as hurricanes or
from the large waves they can create. Another reason they may be