Coastal erosion is a problem faced by all the coastal populations in different
parts of the world. With a long coast of about 7500 km, the subject of
coastal erosion and control in India assumes great importance. This
problem calls for the protection of houses, cultivable lands, valuable
properties, monuments etc. in the coastal belt. The solution to this problem
involves scientific analysis of the same with a view to devise methods for
preventing and/or minimizing the damage due to erosion caused by the
destructive forces of the waves.
It is well known that the erosion of coast is mainly due to the action of waves
in addition to the currents set up by the oblique attack of waves. Erosion of
the coast depends on many factors like storm waves, nature of the beach,
beach material and the shape of the coast, tidal level changes, movement
, and quantity of the littoral drift material. Human interference is also an
important factor causing coastal erosion. The best natural defense against
erosion is an adequate beach on which waves expend their energy.
However, provision of an adequate beach is rarely possible due to
economical reasons. Resort has, therefore, to be taken to provide
appropriate engineering structures such as seawalls, revetments, anti-sea
erosion bunds, groins, offshore breakwaters, etc. to prevent beach erosion.
Seawalls, revetments and groynes are structures located on the beach, while
offshore breakwaters are located away from the beach. Since waves are the
prime cause of beach erosion, it is natural that the protective methods are
evolved so as to dissipate the energy of waves either by absorbing this
energy on the beach or dissipating/diverting the same before the waves
approach the beach. Rubble mound seawalls are the most commonly used
measure for preventing coastal erosion in India.