4. Coastal Erosion and Protection Measures Including Case Studies
109
|%g GROINS
EXISTTNG SHORELINE
gZEj DEPOSITION
BEACH
«—INITIAL SHORELINE
Wave
DIRECTION OF NETLONGS1ORE TRANSPORT
direction
E3Groins
ODeposition
—Initial shoreline
Existing shoreline
Fig. 4.7(b) Typical shoreline évolution due to a groin field.
Drift direction
Fig. 4.7(c) Effect of spacing between groin field (poor rétention for increased
spacing).
CT Groin s
F71 Déposition
«—Initial shoreline
Drift direction
Fig. 4.7(d) Effect of transition groin field (progressive réduction in the déposition of sédiments).