COASTAL PROCESSES
The
coast is the zone between land and sea. The action of waves and sea, constantly
change the form and shape of the coast. Coastal and shelf processes include
wind, waves, currents, climates and tides. This processes influence the
distribution of salinity, sediments, and water borne particles that shape the
coast, seabed, water quality and distribution of marine life within the water
body.
coast is the zone between land and sea. The action of waves and sea, constantly
change the form and shape of the coast. Coastal and shelf processes include
wind, waves, currents, climates and tides. This processes influence the
distribution of salinity, sediments, and water borne particles that shape the
coast, seabed, water quality and distribution of marine life within the water
body.
There
are five main processes which cause coastal erosion. This include hydraulic
action, attrition, abrasion, corrasion, corrosion/solution.
are five main processes which cause coastal erosion. This include hydraulic
action, attrition, abrasion, corrasion, corrosion/solution.
Hydraulic
action is the action of waves and flowing water in the
removal of rocks and sediment from a coastline. In other words, it means that
the coastal erosion is carried out by water and waves.
action is the action of waves and flowing water in the
removal of rocks and sediment from a coastline. In other words, it means that
the coastal erosion is carried out by water and waves.
Attrition
is the breaking down of rocks into smaller particles as a result of collision
with one another. In other words, the water brought into the coast consists
just more than water. It also contains rocks, sediments and particles which
collide with rocks already present at the coastline, breaking them into smaller
and smoother units or particles.
is the breaking down of rocks into smaller particles as a result of collision
with one another. In other words, the water brought into the coast consists
just more than water. It also contains rocks, sediments and particles which
collide with rocks already present at the coastline, breaking them into smaller
and smoother units or particles.
Abrasion
is the sand-paper action of particles
rubbing against the coastline. This sand-paper action actually causes corrasion.
This two are very similar and are classified together by some sources. Flowing
water may contain rocks, sand and sediments which may rub against the floor of
the coastline. This ‘rubbing’ action, causes a sand-paper effect on the coast
which causes wearing on the surface. Simply put, corrasion is the wearing
away of the coastline by abrasion.
is the sand-paper action of particles
rubbing against the coastline. This sand-paper action actually causes corrasion.
This two are very similar and are classified together by some sources. Flowing
water may contain rocks, sand and sediments which may rub against the floor of
the coastline. This ‘rubbing’ action, causes a sand-paper effect on the coast
which causes wearing on the surface. Simply put, corrasion is the wearing
away of the coastline by abrasion.
Water
flowing to the coastline may contain chemicals which can react with other
chemicals at the coast. This reaction causes a solution which is more or less,
a homogenous mixture of the constituent chemicals, resulting in a gradual and
eventual deterioration and breakdown of the coast.
flowing to the coastline may contain chemicals which can react with other
chemicals at the coast. This reaction causes a solution which is more or less,
a homogenous mixture of the constituent chemicals, resulting in a gradual and
eventual deterioration and breakdown of the coast.
Wave action
is the dominant mechanism in both erosion and deposition along coastlines.
is the dominant mechanism in both erosion and deposition along coastlines.
Waves
are powerful due to their pounding action but are also very selective in
etching out rock weaknesses and controlling sediment deposition.
are powerful due to their pounding action but are also very selective in
etching out rock weaknesses and controlling sediment deposition.
The
largest and most powerful waves are those which have travelled furthest, i.e. have the greatest fetch.
largest and most powerful waves are those which have travelled furthest, i.e. have the greatest fetch.
Large storm waves
are powerful and destructive.
are powerful and destructive.
Tidal surges cause
damage when waves reach new heights; they occur on high spring tides, aided by strong onshore winds and low
atmospheric pressure, as in the North Sea, 1953, and at Bangladesh, 1970.
damage when waves reach new heights; they occur on high spring tides, aided by strong onshore winds and low
atmospheric pressure, as in the North Sea, 1953, and at Bangladesh, 1970.
CLIFF EROSION
Coastal erosion occurs often by wave action at beach
level. This creates a wave notch, which advances, leaving a wave cut platform,
and undercutting the cliffs – which retreat by a sequence of rock falls (or
larger landslides in weak material).
level. This creates a wave notch, which advances, leaving a wave cut platform,
and undercutting the cliffs – which retreat by a sequence of rock falls (or
larger landslides in weak material).
Selective
wave erosion of strong rock cliffs etches out faults,
joints and weaknesses to form sea caves, arches and inlets which retreat
between headlands and sea stacks.
wave erosion of strong rock cliffs etches out faults,
joints and weaknesses to form sea caves, arches and inlets which retreat
between headlands and sea stacks.
Coastal
equilibrium produces slowly eroding headlands between
bays where soft rocks are protected by beach deposition.
equilibrium produces slowly eroding headlands between
bays where soft rocks are protected by beach deposition.
Originally posted on January 15, 2020 @ 3:20 pm
