How can we
restore the shore?
Slide: 1
Natural Approaches to
Solving the Beach Erosion
Problem
• Dune Building
• Beach Replenishment
Slide: 2
Erosion Solution: Dunes
• Dunes are hills built by water flow
– Habitat for flora and fauna
– Protect from erosion and encourage
deposition
Dune building can be
done using natural
means or it can be done
using man made
structures.
Slide: 3
Natural:
planting vegetation
Man Made Structures:
using sand fencing
Dune building method #1 Slide: 4
Use of Vegetation
Sand dune stabilization:
Sand dune stabilization is a coastal management technique
for preventing erosion. Sand dunes trap sand and
beach material that is washed up or blown up to the shore. The
rate of erosion is slowed and an effective flood barrier is
created. Footpaths will also have to be introduced to stop
trampling. Sand dune stabilization is economical,
environmentally friendly, does not disrupt the coastline further
on, creates natural habitats for animals and plants and is not
regarded as unattractive. However, for successful dunes to be
placed it must be thoroughly researched beforehand and will
take a long time to establish. Sand dunes may be stabilized
through the planting of vegetation. Vegetation encourages dune
growth by trapping and stabilizing blown sand.
Slide: 5
It is clear to see
that people have
tried to help
save the dunes
in this area by
planting
vegetation
Slide: 6
The plant
life here,
has helped
to capture
the blowing
sand.
Slide: 7
The shore side of the dune…
Slide: 8
This picture shows the leeward (land) side of the dune. Write a claim about the
amount of vegetation on the windward (ocean) side of the dune. Support with
reasoning.
Slide: 9
Inland →
←Shore
Look at the vegetation that is nearest the shore.
Compare it to the vegetation that is further inland.
Slide: 10
How does vegetation help to save
the beaches?
Slide: 11
These diagrams
show how the
natural action of
the waves helps
to restore
eroded
beaches.
This occurs in a
natural cycle.
Slide: 12
Dune Building Solution #2:
Temporary Fences
• Standard slatted wood sand fencing is
ideal for dune-building structures because
it is inexpensive, readily available, easy to
handle, and can be erected quickly.
Slide: 13
Slide: 14
Slide: 15
Plastic fencing has the advantage of
being strong, durable, and reusable,
and it won't be taken for campfire
fuel. Plastic fencing, however, is
about three times as expensive as
wooden sand fencing.
Slide: 16
Keep our beach areas beautiful!
For aesthetic reasons, for safety,
and to avoid interference with
public access, dune-building
structures should be removed as
soon as they have served their
purpose. Sand collected by
structures should be stabilized with
appropriate vegetation.
Slide: 17
Keeping pedestrians off the
dunes !!
Elevated walkovers can prevent damage to dunes
from pedestrian traffic. If walkovers are conveniently
placed near access roads, parking areas,
beachfront subdivisions, and public facilities,
pedestrians will be less likely to cut foot paths
through the dunes to the beach. The presence of
walkovers may increase public awareness of the
value and fragility of sand dunes.
Solution: Slide: 18
Beach Replenishment
More than 70% of Earth's shorelines are retreating due to rising
sea levels. As shorelines move landward, structures located on or
near the beach may be destroyed. In addition, communities
may lose significant amounts of income if they lose the use of
their beaches.
It is, in fact, the interaction of the natural migration of the beach
with the placement of beachfront structures creates the
demand for shoreline protection. If no homes, roads or
businesses were built in the coastal area, beach retreat might be
seen more as the fundamental process that it is and not as a
threat that should be corrected. Shorelines moving landward do
not necessarily mean that beaches will vanish.
Slide: 19
Beach nourishment: A beach is
the perfect defense against wave
action and, if a beach is poor,
one option may be to undertake
beach nourishment. This
basically involves adding large
quantities of material to a beach
in order to build it up. The
material added will need to be
very similar to the material
naturally found on the beach.
This barge is taking the sand from
further out in the ocean and
shooting it onto the beach. This is
called dredging.
Offshore dredging can provide a
good source of suitable material
for beach nourishment. This
involves importing sand off the
beach and piling it on top of the
existing sand. The imported
sand must be of a similar quality
to the existing beach material so
it can integrate with the natural
processes occurring there,
without causing any adverse
effects.
Slide: 20
The barge that is dredging in this picture is shown
far out in the ocean. The pipes on the beach carry
the sand from the barge to the beach.
Slide: 21
Here, the sand is deposited on the
beach from the pipeline.
Slide: 22
Another picture of beach
replenishment from dredging.
Bulldozers are then used to
spread the sand around the
newly restored beaches.
Slide: 23
Slide: 24
Let’s examine how erosion and deposition
have played an important role in creating a
beach that you may be familiar with.
Slide: 25
This is Sandy
Hook New Jersey.
It was created by
the act of
deposition.
Sand from the
south is brought
to the north by a
current known as
the Longshore
Current.
Longshore Current Slide: 26
North
South
As the Longshore Current is moving northward, the ocean
tides and waves pull the sand to the beach. These actions
sometimes work against each other. Sand is therefore
deposited in many new places as it moves along the
shoreline.
Slide: 27
Notice how the water current and waves stir up the water and carries it
along to a new place depending on the direction the current is flowing.
You may have felt the effects of a current while standing on the
shoreline. It pulls you farther north or south without you
realizing it.
Slide: 28
Sandy Hook New Jersey
The shape of Sandy
Hook is also due to
the actions of people
to try and restore the
southern beaches
from erosion.
Notice the V shaped
extensions of beach
on the eastern shore
line.
Sandy Hook beach was once a sand
bar that formed into a peninsula by a
northern flowing current called the
long shore current.
As the current pulls sand from
southern areas of the New Jersey
shoreline, it deposits the sand at
Sandy Hook in the north.
Now that Sandy Hook is a peninsula,
it still feels the effects of the long
shore current.
The southern beaches of Sandy
Hook erode a bit each year while the
northern beach continues to grow.
Let’s examine the process of erosion
that is occurring on the southern
beaches and ways that this can be
fixed.
Slide: 29
Solution:
Slide: 30
Groins and seawalls can be used to
help restore the beaches.
Slide: 31
Groins, or
jetties as they
are sometimes
known, are
often made of
rock, wood or
concrete. They
are placed
perpendicular
to the beach to
catch sand as
it travels north.
Slide: 32
Erosion Solution: Groins
• Groins are structures
that interrupt water flow
and limit erosion
Slide: 33
Examine the
picture of
Sandy hook
again. Why
do you think
the beach
has this V
shaped
formation on
the eastern
shoreline?
Slide: 34
Erosion Solution: Sea Walls
A sea wall is a wall that is built along the beach
– Absorbs no water
– Completely prevents both deposition and erosion
Sea walls
Slide: 35
A seawall is a structure which is designed to protect a shoreline
from flooding and erosion. Essentially, a seawall acts as a layer between
the vulnerable coastline and the ocean. Wave action can beat at the
seawall without eroding the coast, although the seawall itself will
eventually break down and require repair or replacement. Seawalls also
help to insulate communities from flooding, although high waves can still
rise over most seawalls. A seawall can also provide a space for
recreation, since the top of a seawall is often flat, allowing people to walk
on it or to fish from it.
Run for the hills! More storms are
on the way. What will happen to
our beaches?