Beaches
Being a unique boundary between land, water, and air, beaches are very
dynamic forms of land. Waves continuously operate on the beach, putting beach material into
motion. Winds and
tides are also important
forces acting directly on
the beach and causing
changes. Also altering
the nature of the beach
is human interference.
Building of breakwaters,
piers, jetties, and
sea walls can disturb
the natural movement
of beach material and
can cause profound
changes.
During the monsoons, very high waves dissipate their energy, causing
beach erosion and damage to nearshore landforms and property. During
fair weather, low-energy waves help build up beaches by deposition or
accretion of sand. One of the important features of wave action near the
shore is the generation of nearshore currents (Fig. 27). These water movements,
which can be longshore or offshore, are fundamental to the movement
of beach material. Also to be noted is the increased intensity of these
currents during the monsoon, which would be hazardous for those who
venture into the sea for recreational activities. Strong currents directed
towards the sea, perpendicular to shore, are called ‘rip currents’ or ‘killer
currents’, and one should be careful of them.
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