This document discusses coastal processes and erosion. It describes coastal erosion as the loss or displacement of land along coastlines due to natural forces like waves, currents, winds and storms. Coastal erosion becomes a problem when people build structures in erosion-prone coastal areas. It also discusses coastal hazards from rapid events like cyclones and tsunamis, as well as slow erosion. Human activities like sand mining, dredging and coral mining can exacerbate coastal erosion. The document outlines natural causes of erosion like wave action, winds and tides, as well as catastrophic events. It notes challenges with perceiving coastal hazards and adjusting to them through engineering structures, which may protect some property but ultimately damage beaches.

1. COASTAL
PROCESSES
BY:
THOMAS CHINNAPPAN . A ,
M.SC.APPLIED GEOLOGY,
PERIYAR UNIVERSITY,
SALEM.

2. COASTAL EROSION
• Coastal erosion is the loss or displacement of land, or the long-
term removal of sediment and rocks along the coastline due to the
action of waves, currents, tides, wind-driven water, waterborne ice,
or other impacts of storms.
• Coastal erosion is a natural process rather than a natural hazard; erosion
problems occur when people build structures in the coastal zone.

3. COASTAL HAZARDS AND
ENGINEERING STRUCTURES
• Coastal hazards are physical phenomena that expose a coastal
area to risk of property damage, loss of life and environmental
degradation. Rapid-onset hazards last over periods of minutes to
several days and examples include major cyclones accompanied
by high winds, waves and surges or tsunamis created
by submarine earthquakes and landslides. Slow-onset hazards
develop incrementally over longer time periods and examples
include erosion and gradual inundation

4. HUMAN CAUSES IN COASTAL
EROSION
• The mining of sand and gravel along beaches and in the surf-zone will cause
erosion by depleting the shore of its sediment resources.
• In connection with maintenance dredging of tidal inlets, harbours, and navigation
channels, sand is very often lost from the littoral budget because the sand,
unless otherwise regulated by legislation, is normally dumped at deep water.
• Coral mining and other means of spoiling the protective coral reefs, for example,
fishing by the use of explosives or pollution, will also cause coastal erosion and
beach degradation.

5. • Major Causes of Coastal Erosion
Natural CausesAction of Waves: As waves move towards the shore,
waves break and the turbulent energy released stirs up and moves the
sediments deposited on the seabed.
• The wave energy is a function of the wave heights and the wave periods.
• Winds: Winds acts not just as a generator of waves but also as a factor of
the landwards move of dunesTides:. During high tides, the energy of the
breaking waves is released higher on the foreshore or the cliff base (cliff
undercutting)Catastrophic events events like tsunamis which result in
major coastal changes over very short time periods.

6. PERCEPTION AND ADJUSTMENT
TO COASTAL HAZARDS
• From 1978 to 1982, $43 million dollars in federal flood insurance was paid in
damage claims to barrier-island residents, which far exceeded the premiums
they paid.
• It is becoming increasingly obvious that the most sensible thing to do with
many such structures is to abandon the costly and ultimately doomed efforts
to protect or maintain them, and simply leave these areas in their dynamic,
natural, rapidly changing state, most often as underdeveloped recreation
areas.

7. • From a philosophical perspective:
• Any shoreline construction causes change.
• Engineering structures designed to protect a beach may eventually destroy it

8. • Stabilization of the coastal zone through engineering structures protects the
property of relatively few people at a larger general expense to the public.
• Once constructed, shoreline engineering structures produce a trend in
coastal development that is difficult if not impossible to reverse.

9. THANK YOU