Beach Renourishment Principles - Beach Renourishment - page 46

but erosion began on Holloways Beach when the mouth of a distributary that had
been supplying sand was diverted northward to Richter Creek during a 1938 flood.
Deprived of a sand supply, Holloways Beach began to erode as sand drifted away
northward. In 1992 a 600 m sector of this beach was renourished with 83,000 m 3
of sand dredged from the lower reaches of Richter Creek and delivered to
Holloways Beach by lorries, essentially an artificial revival of the fluvial sand sup-
ply that originally built this beach. Maintenance of such deltaic beaches could also
be achieved by relocating the mouth of a river distributary so that it fed sand to the
updrift end of a resort beach.
Sand from the Mississippi River has been used to restore beaches and dunes
on Scofield Island, a rapidly-deteriorating barrier island in Plaquemines Parish,
Louisiana. As part of the project planning, Poff et al. ( 2011 ) evaluated the feasibil-
ity of mining and transporting sand from the Mississippi River. Riverine sand was
recommended as an alternative to offshore sources.
4.2.6 Sediment from Tidal Inlets
On barrier island coasts there are often shoal deposits at tidal inlets, formed sea-
ward by ebb tides and lagoon ward by flood tides. It is necessary to consider the
possible impacts of extracting sediment from such shoals, such as the effects on
wave and current regimes in the inlet, and the possibility that changing wave
patterns will have adverse effects on the adjacent coastline. At Captiva Island in
Florida resort beaches were renourished with sand dredged from ebb-tide shoals
off the nearby inlet at Red Fish Pass. This extraction proved beneficial because it
modified the wave refraction pattern in such a way as to stop sand drifting back
from the renourished beach into the inlet. Sand was also available from flood-tide
shoals just inside Red Fish Pass, but this was not used because of the risk that
deepening this area would induce sediment inflow and result in erosion alongside
the inlet (Walton and Dean 1976 ). At Palm Beach on Australia's Gold Coast, sed-
iment has been dredged from inside the mouth of nearby Currumbin Creek and
used to renourish the southern end of Palm Beach. Dredging has taken place at
least once a year for the last three decades. Sediment is pumped onto the beach by
pipes then a bulldozer is used to distribute the sand along the beach.
4.2.7 Sediment from the Sea Floor
Sand and gravel dredged from the sea floor has been widely used for beach renour-
ishment in such places as Seaford in England, Ostend in Belgium (Sect. 4.3.1 , p.
56), Port Dickson in Malaysia and Miami Beach in Florida (Sect. 4.3.8 , p. 73/74).
Nearshore shoals have provided sandy sediment for beaches on Nordeney in
Germany (Sect. 4.4.2 , p. 80), on the Adelaide coast in South Australia (Sect. 4.3.4 ,