Environmental Engineering Reference
In-Depth Information
Fig. 4.13
Beach renourishment taking place at Ostend, Belgium in 2013. Sand extracted from
the seafloor was pumping directly from the dredge barge to renourish the beach and nearshore
areas. © Afdeling Kust
At Seaford in East Sussex beach erosion began after the building of the large
breakwater at Newhaven in 1845, which cut off the supply of shingle drifting
in from the west. As Seaford beach was depleted, storm waves became increas-
ingly destructive, and a sea wall was built to protect the esplanade, with numerous
groynes inserted in the hope of retaining what was left of the shingle (Fig.
4.14
),
which was augmented artificially in 1963. Beach erosion continued despite suc-
cessive elaborations of the structures. Eventually, in 1987, the shingle beach was
renourished by the Southern Water Authority with 1.5 million m
3
gravel dredged
from the sea floor off Littlehampton, to the west, dumped a kilometre offshore,
then pumped on to the shore, where it was deposited over an armouring of
large granite blocks imported from Galicia in Spain. The restored shingle beach
was then shaped by bulldozers into a broad terrace with a seaward outer slope
(Fig.
4.15
), and a retaining groyne at the eastern end (Nicholls
1990
).
A similar technique has been used to restore the depleted shingle beach at
Sidmouth in Devon. Protected by sea walls built in the 19th century, this south-
facing seaside resort had been steadily losing its beach, partly because the adja-
cent cliffs of soft sandstone have continued to recede, so that the esplanade stands
slightly forward from the general coastline. In consequence, the seafront was more
exposed to wave scour, which dispersed the shingle beach alongshore, mainly
