Environmental Engineering Reference
In-Depth Information
Fig. 4.22
On the coast near
Rye in Sussex longshore drift
carries shingle from Cliff End
(
A
) to accrete alongside the
River Rother breakwater (
B
),
and from here it is recycled
by lorries that take it back to
Cliff End. © Geostudies
to intercept this drifting shingle and form a wide beach. In 1934 some shingle was
taken from the accreting area adjacent to the Rye breakwater and returned to the
depleted beach to the west, using a beach railway. In 1955 the Kent River Board
began regular ferrying of lorry loads of shingle taken from alongside the breakwater
round to the western end and dump them to restore the depleted beach (Fig.
4.22
): in
the first year 155,000 m
3
of shingle was returned to the SW end of the beach, and in
subsequent years similar quantities were recycled (Eddison
1983
).
On the Adelaide coast in South Australia sand lost from the southern beaches
has drifted north towards Port Adelaide, where the wide beach has been used as a
source of sand trucked back southward to the eroding beaches (Fig.
4.23
) (Wynne
1984
). Since 2010 it has been found more practical to recycle sand on a smaller
scale within selected beach compartment (Fig.
4.24a
,
b
).
At Noosa, on the east coast of Australia, a hydraulic system of recycling was
installed in 2004 to replace previous recycling efforts which included dredg-
ing of Noosa Sound. The hydraulic system collects sand from the downdrift end
of the beach and pumps it back along the beach to provide beach nourishment
(Nankervis
2005
). The system is permanently installed and operated regularly to
provide a constant supply (35,000 m
3
/year) of sand to Noosa Beach.
Alternatively, recycling can be carried out by barges travelling along the shore,
as on the Caucasian Black Sea coast (Sect.
4.2.4
, p. 47) or by pumping the sand
back from the updrift end of the beach through a pipe, as at Narva Bay in Estonia.
Recycling has the advantage that the shape and size characteristics of the sediment
