Environmental Engineering Reference
In-Depth Information
Fig. 4.8
The artificial beach
in Carlyon Bay, Cornwall,
was supplied with sand and
gravel waste from tin mining
in the hinterland, delivered
through a tunnel cut from the
Homebush valley.
© Geostudies
bay to the north, which had a rocky shore with stacks in front of cliffs. By 1985
this had acquired an artificial beach more than 5 km long and up to 300 m wide.
A major potential source of sediment suitable for beach renourishment in
south-west England exists in the tip-heaps of quartz and feldspar sand and gravel
in the china clay quarrying region of Hensbarrow Down, near St Austell in
Cornwall. There is a similar, smaller area in south-western Dartmoor, which was
used to replenish a small beach at Torpoint, near Plymouth.
Colliery waste was dumped on the shores of County Durham, England
for more than a century, until the closure of the coal mines in recent years
(Hydraulics Research Station
1970
; Nunny
1978
). Deposits of dumped waste
have been reworked and drifted alongshore for several kilometres, augmenting the
natural beaches of locally-derived calcareous sand (Fig.
4.9
). The added coal and
shale have been sorted into gravel and sand, and in some places coal fragments
were collected from the shore, mainly for domestic use. Wide, convex beaches
formed, but after dumping was halted, the beaches were cut back by wave action,
and low clifflets or beach scarps were formed, fronted by a developing concave
profile.
Fig. 4.9
The beach at
Ness Point, near Seaham in
Durham, was augmented
by the dumping of gravelly
waste from nearby coal
mines. Dumping ceased
when nearby coal mines
were closed in 1993, and the
beach is being re-shaped by
wave action. A low clifflet
(
arrowed
) marks scarping at
the limit of wave re-working.
© Geostudies
