Environmental Engineering Reference
In-Depth Information
become very narrow in winter, when the backing bluff was undercut by storm
wave erosion, forming slumping cliffs of sandy clay up to 10 m high (Fig.
5.4
). As
these were cut back, there was a risk that a segment of the coastal highway, which
here runs close to the top of the bluffs, would be undermined.
In 1990 a groyne was built at Edward Street and the sector south to Red Bluff
renourished to form a beach 25 m wide and 600 m long by trucking in about
35,000 m
3
of sand, placed to protect the base of the bluffs from further storm
wave erosion (Fig.
5.5
). As a result the undercutting of the bluffs ceased (Fig.
5.5
).
Some slumping continues because of groundwater seepage from the bluff, but by
2004 the cliff base had become largely revegetated. Protection of a cliff base by
Fig. 5.4
Erosion of
backshore bluff on a sector
of Sandringham Beach,
Port Phillip Bay in 1989.
© Geostudies
Fig. 5.5
After the
renourishment of the of
Sandringham Beach, Port
Phillip Bay, south of the
Edward Street groyne, in
1990, backshore cliff erosion
halted and vegetation revived.
© Geostudies
