Notes on Coastal Studies
1.
What is a coastal environment?
A
coast is the area where the sea or ocean meets the land.
What
factors lead to the differences and dynamism of coastal environments?
• Waves
• Currents
• Tides
• Geology (rock composition)
• Human activities (e.g.
trading, fishing, recreation)
• Types of ecosystems (e.g.
mangroves and coral reefs)
Waves
·
It is the main shaping force of coastal
environments
·
Waves form when wind blows across the surface
of seas and oceans
·
Energy from the wind is transferred to the
water and it is this wind that helps shape coasts when the waves hit land
Currents
- They are large-scale
and persistent movements of water in seas and oceans, driven by prevailing
winds (generally blow in one direction)
- Ocean currents play a
very important role in distributing sediments and regulating temperatures
- Currents (e.g.
longshore currents) carry large
amounts of energy and shape coasts through the processes of coastal
erosion, sediment transport and sediment deposition
- Ocean currents carry
cool water away from the North and South poles towards the Equator and
warm water from the Equator towards the Poles
- In this way, ocean
currents help create milder climates in coastal areas
Tides
- Refer to the daily alternate
rising and falling of the sea level seen along the coasts
- They are caused primarily by the
gravitational pull of the Moon and the Sun on the earth
- Low tides are experienced between
the high tides and takes about 6 hours for tides to change
- Each coastal area receives two high tides and two low tides daily and the difference in water level between low and high tides is called the tidal range
- Tidal action has a significant
impact on the coast
- For example at high tides, waves erode
and transport more sediments away from the larger parts of the coasts than
at other times
- Areas located between low and
high tides will have more weathering and erosion than areas constantly
submerged by sea water
Geology
·
Coastal environments are affected by their
geology, which is the arrangement and composition of rock found in the area
·
Rocks may be arranged in layers, such as in
alternate layers of hard and soft rocks
·
More resistant
rocks such as granite and basalt will erode slower than less resistant rocks such as limestone and
shale
·
But granite and basalt are still vulnerable
to erosion when the joints of these rocks are attacked by waves, thus erosion
weakens the rocks
·
Coastal processes that operate on coasts
consisting of different types of rock result in coasts with different
coastlines
Human activities
·
People change coastal environments by living,
trading, fishing and engaging in recreational activities in these environments
·
For example, people alter coastlines when
they build marinas and port facilities
·
People also cause pollution in these
environments by dumping waste
Types of ecosystems
·
Communities of plants and animals interact
with each other as well as the environment and ecosystems in coastal
environments include mangroves and coral reefs
·
They affect the rate of change of coastal
environments by reducing the impacts of waves on coasts
·
For example, coral reefs provide natural
barriers that help slow down the speed and impacts of waves on the coastline
·
Another example is mangroves with aerial
roots, help to trap sediments and reduce coastal erosion
·
Over time, the trapped sediments can form
small islands and extend the coastline further seawards
2. Explain how waves are generated and
the factor influencing wave energy.
Waves
are generated when there is a transfer of energy from wind to water surface
Wave
Energy
- It is the energy
produced by the movement of waves
- Wind energy depends
the fetch, the wind speed and the wind duration
Factor
|
Description
|
Size
and energy of waves
|
Fetch
|
The
distance of the sea over which wind blows to generate waves
|
The
greater the fetch, the more energy the waves have
|
Wind
speed
|
The
speed of air movement
|
The
faster the wind speed, the greater the waves energy
|
Duration
of wind
|
The
length of time which the wind blows continuously
|
The
longer the wind blows, the larger the waves
|
3. Explain the processes which occur
when waves breaks.
The forward movement of waves up the
shore is called swash (loses energy due to gravity)
The flow back to the sea (due to
gravity) is called backwash
The swash carries sediments up the shore while the backwash carries the sediments back towards
the sea.
5. Describe the different
types of waves and their associated coastal environment.
Constructive waves
|
Destructive waves
|
|
|
6.
Explain wave refraction and the processes which occur when waves break.
·
The process by
which waves change direction when they approach a coast
·
Waves converge on
headlands and diverge on bays
·
When waves converge
– increased wave height and greater erosive energy
·
When waves diverge
– decreased wave height and lower erosive energy
·
Uneven impact on
shoreline
Fig. 4: Action of wave refraction on headland and
bay
At
the headland – waves approach a headland and bend towards it. More erosion will
occur at the headland where wave energy is concentrated.
At
the bay - waves diverge when they reach the adjacent bays. More deposition will
occur in bays where wave energy is spread out.
7.
Why do coastal landforms and features vary from place to place?
Coastal
Processes
A. Coastal Erosion
B. Coastal Transportation (Sediment
transport)
C. Coastal Deposition (Sediment deposition)
A) Coastal Erosion
Factors
affecting coastal erosion
Types
of waves
|
Structure
and composition of coastal rocks
|
Position
of the coast
|
·
Destructive
waves have more energy therefore more materials are eroded than deposited
|
· Coastal rocks with cracks
and joints
will be eroded and broken down more quickly when attack by waves
· A coast that consists of soft
rocks such as shale and clay will be eroded much faster
· Coastal rock with soluble
minerals can chemically react with water to form new chemicals, which may
gradually weakened and broken down under the constant attack of sea water
|
· Coasts that are protected
or sheltered from prevailing winds and wave action by natural or man-made
structures will experience less erosion than coasts that are open and
unprotected
|
Processes
of Coastal Erosion
Type
of coastal erosional processes
|
Description
|
Hydraulic
action
|
· It is the direct impact
of the waves against the coast
· The sheer force of
breaking waves pounding against a sea cliff exerts great pressure on the
cliff face
· Air in the cracks may be compressed
by the water entering the cracks and the pressure exerted can widen the
cracks
· Over time, this constant
compression and outward push of the air may cause the cracks to be enlarged
· Eventually, it will cause
the breakdown of the rocks
|
Abrasion
|
· Refers to the impact of
materials carried by the waves scraping/ hurling against the coast
· Destructive waves are
capable of lifting up large pieces of rocks from the sea bed and hurling them
against the coast
· This powerful impact of
the rocks being thrown against the coast may eventually erode and change the
coast
|
Solution
|
|
Attrition
|
|
B) Coastal Transportation
- One way of transporting sediments
along the coast is by beach drift
and longshore drift
- When waves approach the coast at
an angle, the swash carries the
materials in the water up the beach at an oblique angle, while the backwash carries the materials perpendicularly
down the beach due to the pull of gravity
- This results in a zigzag movement of the materials along
the beach
- This process is known as beach drift
·
When the waves approach the coast at an
angle, they generate longshore currents in the nearshore zone and move
sediments along the shore
·
Longshore
currents
are ocean currents that flow parallel to
the coast
·
The
combined effect of sediment movement by longshore currents and beach drift is
known as the longshore drift
- The direction of the longshore
drift is affected by the direction of the wind
- For example, if the wind is
blowing from a southeast direction, the direction of the longshore
drift will be from east to west
- This is a powerful process that
is capable of moving very large amounts of beach sediments along the
direction of movement
C) Coastal Deposition
Sediments
are transported away and deposited elsewhere. When wave energy decreases, the
waves are unable to carry these sediments. Marge sediments are deposited first,
followed by the smaller sediments. Deposited sediments vary in types and size,
resulting in a variety of beaches.
Deposition
of sediment along the coast is dependent on the following factors:
Supply of sediments
|
Gradient of slope
|
Position of the coast
|
|
|
|
In what ways do coastal landforms and
features vary from place to place?
Different
coastal landforms such as sandy beaches, rocky beaches or steep cliffs may be
found along coasts. These are largely the result of erosional and depositional
processes.
Erosional Landforms
|
Depositional Landforms
|
|
|
Formation
of Cliffs and Wave-cut Platforms
- A cliff refers to a
steep rock face
- Can either tilt
forward or backwards
- They are produced by
the action of waves undercutting a steep rocky coast
- Hydraulic action and abrasion
may erode a crack on the rock surface
- Eventually, the crack
may be enlarged to produce a notch
- This notch may be
further deepened inwards to produce a sea
cave
- Further undercutting
by the waves will eventually cause the roof of the sea cave to collapse
- As the process
continues, an overhanging cliff is
formed
- The overhanging cliff will collapse
and the materials will be deposited at the foot of the cliff
- Some of these materials
may be picked up by the crashing waves and thrown against the base of the
cliff, thus causing further erosion
- As the erosional
process continues, the cliff may
retreat further inland
- Over time, a gently-sloping platform appears at the
base of the cliff and this platform is called the wave-cut platform,
which is usually submerged during the high tides
- The wave-cut platform is also known as the shore
platform
Headlands
and Bays
Some coastlines have alternate
strips/ bands of resistant hard rock and less resistant soft rock arranged
at right angles to the coast
- The less resistant
soft rocks will be eroded faster than the more resistant hard rocks
- When the less
resistant soft rocks are eroded away, bays are formed
- The remaining more
resistant hard rocks extending into the sea are known as headlands
- The result is the
formation of indented coasts with headlands and bays
- For example, East coast of Johor, Malaysia and South coast of United
Kingdom
- Headlands and bays give rise to wave refraction
- Waves usually approach
the shore at an angle
- However, as waves approach an indented shore with
headlands and bays, the waves
are refracted or bent
- Consequently, they
move almost parallel to the shore
- The refraction is caused by the uneven
depth of the sea-floor
- As the waves bend,
their energy is distributed unevenly along the shoreline
- The waves nearer to the shore touches
the sea floor first and slows down
due to friction with the bottom of the sea
- Meanwhile the waves at
the back continue to move towards the shore at full speed
- As a result of wave
refraction, waves approach the
shallow sea in front of the
headlands first before they reach the adjacent bays
- As wave energy tends to concentrate and
strike at the headlands rather than the bays, erosion takes place at
the protruding headlands
- Along the bays, waves are diverged and their energy spread out and weaken
- Deposition of sediment
thus takes place along the bays and over time, sandy beaches are formed
- Waves refraction,
therefore, determines when and where erosion, transportation and
deposition take place
- It causes erosion at
the headlands and deposition along the bays
- Over time, the
indented coast will become more and more prominent
Caves,
arches and stacks
·
Within headlands,
some rocks may be less resistant to erosion than other rocks. These parts of
the headlands will be eroded more quickly, especially by hydraulic action and
abrasion. Waves attack lines of weaknesses (joints and faults) at the base of
the headland and undercut it. The continuous action of waves forms a cave
(e.g. a cave in Hanauma Bay, USA) at the area that is hollowed by the wave
action.
·
Caves may develop
on each side of the headland. Erosion may eventually join caves together,
leaving a bridge of rock known as an arch (e.g. an arch in Port
Campbell, Australia) above the opening.
·
After a period of
time, the roof of the arch may collapse to form a stack (a stack in
‘James Bond Island’, Thailand). A stack is a pillar of rock in the sea left
behind after an arch collapses.
Beaches
(depositional coasts)
- It the most common
depositional feature found along a coast
- The size and
composition of the materials on the beach vary greatly and may change over
time according to changes in weather conditions, wind direction, wave
energy and ocean currents
- Usually the waves and
winds will cause the materials on the beach to be sorted by size
- The slope of the beach
is determined by grain size. Finer grain sizes tend to result in beaches
with a gentle gradient
- On the other hand,
materials of coarser grains form beaches with a steeper gradient
- Generally, the finer
materials are deposited nearer the sea and coarser materials further
inland if the wind is strong and there is destructive waves
- During calm conditions
with constructive waves, fine materials are deposited further up the coast
and the coarser materials are deposited nearer the sea
Spits
and Tombolos
- It is formed by longshore drift
- Along some coasts
where the direction of the coastline changes abruptly, longshore drift
continues to transport the materials in the original direction for some
distance
- The materials are
deposited in the sea where they accumulate over time
- Eventually, the
accumulated materials will appear above the surface of the water, forming
a spit
- A hook or curve may
develop at one end of the spit, most likely due to wave refraction concentrating
at that point
- A spit has one end
connected to a mainland while the other end projects out into the sea
- When a spit is formed,
it may continue to expand until it joins the island to the mainland
- In this case, a new
landform called a tombolo (e.g. a tombolo found in the Gulf of
Thailand) is formed
- A tombolo may also
join two islands
The Coral Triangle spans an area of 6 million
square kilometres. It consists of countries such as Indonesia, Malaysia, the
Philippines, Papua New Guinea, Timor Leste and the Solomon Islands. 76 per
cent of the world’s coral species, 6 out of 7 of the world’s marine turtle
species, and at least 2,228 reef fish species live in this area.
The Coral Triangle region is unique not only because
of its wildlife and marine and coastal ecosystems, but also for the benefits
the local communities and governments can gain from the area.
Consider this:
•
120 million people are directly sustained by
the marine and coastal resources of the Coral Triangle
•
US$2.4 billion is the amount that fisheries in
Southeast Asia make from making use of the coral reef ecosystem
•
US$12 billion is the size of the Coral Triangle
nature-based tourism industry
How do people use coastal areas?
|
Humanities
activities in the coastal areas
|
Examples
|
1
|
Fisheries
and aquaculture
Fisheries
are areas where fish are bred and raised to meet the growing demand for fish.
These
fisheries include farming fish in cages or ponds close to coasts in rivers or
converted wetlands, which is known as aquaculture.
|
Ca Mau,
Vietnam
Areas
cleared from coastal mangroves which are waterlogged are favourable for shrimp
production. The remaining mangroves protect the area from storms and coastal
flooding.
Mud and
concrete ponds have been constructed to hold the shrimps production. Production
of shrimp farms reached a record high of US$800 million in 2010.
Clearing
of mangroves has left the coastline more vulnerable to erosion from storms
and pollution pond waste. Thus organic shrimp farming was introduced
to help prevent clearing of mangroves and maintaining a balanced ecosystem.
|
2
|
Housing
and transportation
There are
some people who live on stilt houses, connected by walkways.
Boats are
also there to facilitate movement, and are a common mode of transportation.
|
Kukup,
Malaysia
It is a
place with stilt house communities. Floating fish farms are a common sight.
Fresh fish and other marine products such as salted fish and dried prawns are
sold at these farms.
Boats are
used by local fishermen to facilitate their fishing activities. Visitors can
also use the ferry services to go to Kukup.
Over the
years, Kukup has become an attractive tourist destination, with its economy
largely driven by the income earned from local and foreign tourists.
|
3
|
Tourism
and recreation
People
usually associate coasts with tourism and recreation. Tourism at
coastal areas makes up the most important component of international tourism.
|
Sentosa,
Singapore
Many
developments in Sentosa have capitalized on the coast. One such development
is ONE015 Marina Club which has world-class marina facilities.
Its marina
is in a harbor with wharfs offering maintenance services for boats and
yachts. It also has recreational boating facilities.
Resort
World Sentosa has also maxmised the use of its waterfront by building its
hotels, museum and marine life park on the coast.
With these
attractions, it is not surprising that the island had 19 million visitors
in 2011, a 600% increase from 2003.
|
Why are coral reef and
mangrove ecosystems distinctive and valuable?
|
Coral reefs
|
Mangroves
|
Ecosystems
|
These
reefs consist of colonies containing billions of tiny coral animals called polyps
Polyps
secrete calcium carbonate around themselves as protection
Polyps
leave empty outer limestone skeletons when they die
Provide
microscopic algae with nutrients and CO2, while the algae provide
the polyps with sugars and oxygen, which are products of photosynthesis
Algae
lives in the coral tissue and they have a symbiotic relationship (live
together and benefit each other)
|
Salt-tolerant
tropical or sub-tropical plants which grow in conditions that most plants are
unable to
Grow
in tidal mud on sheltered coasts
Habitat
to many plants and animals
|
Distribution
|
Widely
distributed but are mostly found between the Tropic of Cancer in the
northern hemisphere and the Tropic of Capricorn in the southern hemisphere
Region
of Southeast Asia has the largest area and the highest biodiversity of
coral reefs in the world
e.g.
Great Barrier Reef in Australia, reefs around Philippines and Indonesia.
|
Found
along coasts of countries located between Tropic of Cancer and Tropic of
Capricorn
Most
abundant on tropical coastlines such as the Malay Peninsula, Borneo, northern
Australia
|
Environmental
conditions affecting their growth
|
Strong waves increases the likelihood
of food and oxygen supplies and prevents sediments from suffocating living
corals
Storm waves can destroy
corals
Sediments
suffocate corals
Average seawater salinity
Lower
salinity levels inhibit coral growth e.g. at the river mouth
Clear saline water
(between 10m and 60m deep) allows sunlight to penetrate, triggering algae
photosynthesis
High
turbidity restricts sunlight penetration so algae cannot photosynthesize
efficiently
Sea temperature
must be ideal (not lower than 170C to 180C)
|
Mangroves
are a type of halophyte
Special
aerial roots to enable them to take in oxygen in waterlogged conditions
Prop
roots to anchor the trees firmly in the soft and muddy ground. The roots
ensure that the trees will not be uprooted or swept away by strong waves
Some
mangrove fruits are javelin-shaped so that they can pierce the soft mud to
germinate and grow into sapling immediately
Some
fruits are buoyant, allowing them to float away and germinate in other
coastal areas
Some
species have developed ways to secrete excess salt, through the underside of
their leaves
Many
mangroves show patterns of horizontal zonation, where the structure
and dominant species in each zone varies due to environmental conditions
|
Value
|
Provide food and habitat
to many species of marine fish species. For
example the parrot fish graze on the living coral polyps
Ability to absorb wave
energy generated in the open seas, thus, protecting land
mass from coastal erosion
Tropical
cyclones can damage coral reefs and then the coasts become more prone to
erosion
|
Dense network of roots
help to build up sediment that can protect coastal areas
from erosion by tides, storm waves and tsunamis
Breeding ground and
habitat for a range of marine creatures. For
example, Barnacles, oysters and sponges anchor on the hard surfaces of the
aerial roots.
|
Pressures
|
Development
of coastal areas on a large scale is putting pressure on coral reef
ecosystems
About
75% of the world’s reefs are threatened
But
95% of Southeast Asia’s coral reefs are threatened
|
Since
1980, the world has lost around 3.6 million hectares of mangroves, equivalent
to a 20% loss of total mangrove area.
|
Pressures on coral reef
ecosystems
|
|||
Pressure
|
Activity
|
Impact
|
Examples
|
Over-collection of corals
|
Overfishing
in reefs and surrounding waters.
|
Depletion
of fish disrupts the delicate balance of the ecosystem’s food chain;
predators of these fish have less to feed on while their prey id able to
increase in numbers.
|
Philippines
|
Fishing methods
|
Dynamite
blasting and the use of cyanide to stun fish.
|
Coral
reef habitat is destroyed.
|
Philippines
Indonesia
|
Spearfishing.
|
Selective
depletion of fish population disrupts the ecosystem’s food chain. For
example, parrotfish eat algae that may inhibit coral growth.
|
Belize
Bonaire, the Netherlands
|
|
Recreational use of coast
|
Tourism
activities such as building of facilities, trampling and anchoring of boats.
|
Waste
may be discharged into water and stress corals; boat anchor may damage corals.
|
Sri
Lanka
|
Coastal development
|
Reclamation
and extension of land areas by dumping rock and sand onto reefs.
|
Coral
reefs are suffocated by sediments and are destroyed.
|
Japan
|
Expansion
of coastal resorts and urban housing increases likelihood of more waste being
deposited into the sea.
|
Coral
reefs are suffocated by sediments and are destroyed.
|
Florida,
USA
|
|
Climate change
|
Rapid
changes in sea temperatures and sea levels may be faster than the ability of
the reefs and their associated life forms to adjust.
|
Coral bleaching
occurs when higher sea temperatures result in the loss of algae; this cause
the coral to turn white or be bleached.
|
Seychelles
|
Pressures on mangrove
ecosystems
|
|||
Pressure
|
Activity
|
Impact
|
Examples
|
Demand for fuel wood and charcoal
|
Mangroves
are cleared for fuel and charcoal, particularly in regions with low
technology and low income economies.
|
Fish
breeding grounds are reduced. Also coasts become more open to storm waves.
|
Indonesia
|
Need for more farming
areas
|
Thousands
of hectares of mangroves are converted into paddy fields and shrimp farms.
|
Mangroves
are cleared and coasts become more vulnerable.
|
Vietnam
Thailand
|
Coastal Development
|
Land
if reclaimed for housing, industry and recreational uses.
|
Mangroves
largely disappear from the environment. Moreover, coastal waters are polluted
as a result of human activities.
|
Caribbean
islands
|
Rising sea level
|
Rising
sea levels, together with extreme storm activity, are likely to occur in
future if climate accelerates.
|
Mangroves
will have trouble colonizing areas further inland despite sea level rise as
they will be in competition with human activities such as farming and
construction of sea defences.
|
Gulf
of Thailand
|
How can we manage coastal
areas in a sustainable manner?
How can coastal areas be
managed?
Management
of coastal area means controlling the development and change in the coastal
zone according to agreed principles and criteria. This involves implementing
policies such as restoring sandy beaches at certain places. To enforce this
policy, a strategy or a series of strategies are needed
Coastal
areas should be managed in a sustainable manner, which means development that
should not compromise the quality of the environment for the present and future
generations.
To
manage coastal areas, we can:
·
Limit damaging
activities
·
Protect coastal
resources
·
Restrict
development in areas prone to natural hazards
1) Limit damaging activities
·
Many national and
local government bodies try to limit these activities
·
This is done
through management that aligns the needs and demands of people together with
the nature of the coastal environment
·
For example, sand dunes which are deposits of windblown sand from the foreshore zone
stabilized by plants, were often trampled on by people visiting the beach in
Port Philip
·
Dune vegetation was
being destroyed and the sand dunes were left exposed to wind erosion
·
Houses behind the
dunes were in danger of being partly buried by the large volume of sand blown
by the wind
·
To allow the dunes
to recover, authorities fenced off the dunes and built access paths to the
beach
·
This decision
allowed the coastal environment to recover
·
However, the fences make the beach look less attractive and do not allow
visitors and residents access to all parts of the beach
2) Protect coastal resources
·
Areas close to the
coastlines where around 90% of all marine fish are caught are vulnerable to
overfishing
·
This occurs
especially in the coral reefs areas of Southeast Asia where destructive fishing
methods of blasting and poison fishing are used
·
For example,
Wakatobi National Park in Indonesia and Goat Island Marine Reserve in New
Zealand, zones have been marked off to prevent commercial fishing
·
This is done
through local management or establishment of a marine reserve
·
Marine reserves
protect marine ecosystems which allows fish and endangered species to breed and
thrive
·
The Goat Island
Marine Reserve is now a tourist attraction because of its plentiful fish; there
are up to 14 times more snappers within the reserve than outside it
·
This demonstrates
the positive management impact of protecting coastal resources
·
However, the establishment of marine reserves is often strongly opposed by local
fishermen because they see their access to a valuable resource and food, being
denied
·
The potential
long-term benefits of a marine reserve may not be significant to locals who can
no longer in an area that has supported them for a long time
3) Restrict development in areas prone to natural hazards
·
Tsunamis can be
disastrous to natural environment and human activities
·
For example the
powerful earthquakes in Tohoku in March 2011 resulted in a tsunami of powerful
sea waves that swamped large areas of coastal Japan
·
The tsunami caused
the death of 20,000 people, the destruction of coastal towns and failure of
nuclear power stations
·
The cost of
rebuilding has been conservatively estimated at US$300 billion
·
Despite the
occurrence of natural hazards, people are still attracted to the coasts because
many of the coasts provide natural resources such as food and building
materials
·
Coasts also provide
a substantial range of build services such as docks, ports, housing and
recreational facilities
·
However, residents and
investors of these areas may have to spend more in construction and maintenance
and will also need to be prepared for emergencies
·
Many national
governments and local authorities have developed management policies to deal
with the threat of natural hazards in coastal areas
·
They research on
how severe or widespread the problem is, plan for it, then make and enforce
laws
·
The law and
policies usually involves a combination of the following strategies
Strategies
|
Examples
|
Retreat
or relocation of built structures away from areas prone to natural hazards
|
In
USA, the Federal Emergency Management Agency (FEMA) steers development away
from areas prone to flooding or coastal erosion.
|
Avoidance,
which includes regulating development
|
Indonesian
laws restrict new farms and residences from being established on low-lying
coastal areas.
|
Defence,
such as nourishing beaches, building seawalls and replanting coastal
vegetation
|
Beaches
in the Netherlands are closely monitored and undergo beach nourishment when
long-term erosion is identified.
|
What
are the coastal protection measures?
Measures to protect coasts can be
divided into:
|
|
Hard Engineering
|
Soft Engineering
|
|
|
|
|
Hard Engineering Measures
|
Description
|
Advantages
|
Disadvantages
|
Seawalls
|
|
|
|
Breakwaters
|
|
|
|
Groynes
|
|
|
|
Gabions
|
|
|
|
Tetrapods
|
|
|
|
Soft Engineering Measures
|
Description
|
Advantages
|
Disadvantages
|
Beach
nourishment
|
|
|
|
Planting
vegetation
|
|
|
|
Stabilizing
dunes
|
|
|
|
Encouraging
coral reefs growth
|
|
|
|
THANK YOU VERY VERY MUCH FOR THIS NOTES, IT REALLY OFFERS A LOT OF HELP TO MY GEO !
THANKS THANKS THANKS!!!!!I would thank you from the bottom of my heart, but for you my heart has no bottom.Serious. LOL, i know it sounds corny but who cares! im so thankful!
thanks for the notes
really helped me
Amazing notes it really helped me thank you
tqvm
Thanks for saving me for my prelim. All the best to whoever is using this to prepare for your examination!!
Thanks for saving me for my prelim. All the best to whoever is using this to prepare for your examination!!
cool B)