The document discusses different methods of coastal management used to reduce erosion and protect coastlines. Hard engineering options like sea walls, groynes, and revetments aim to reduce erosion but are expensive and can damage the environment. Soft engineering options like beach nourishment, managed retreat, and beach reshaping are often more sustainable and cost-effective but provide only temporary protection. The document provides details on each method, including how they work, advantages, and disadvantages.

2. Starter:
Mind-map all the different things people use coast
lines for.
What are
Coasts used
for?

3. Some coastlines are under threat of erosion
causing cliffs to retreat and beach material to be
lost. Others are at risk from coastal flooding.
In many cases the decision has been made to
try and reduce the erosion to protect the
coastline. This is called COASTAL
MANAGEMENT.
Coastal Management = The attempt by
people to maintain the natural features of
the coast for their own advantage

4. Types ofTypes of
CoastalCoastal
ManagementManagement
HARDHARD
ENGINEERINGENGINEERING
Hard engineeringHard engineering
options tend to beoptions tend to be
expensiveexpensive andand
short-termshort-term..
They may alsoThey may also
have a high impacthave a high impact
on the landscapeon the landscape
or environment.or environment.
SOFTSOFT
ENGINEERINGENGINEERING
Soft engineeringSoft engineering
options are oftenoptions are often
less expensiveless expensive thanthan
hard engineeringhard engineering
options.options.
They are usuallyThey are usually
alsoalso more long-more long-
term andterm and
sustainablesustainable, with, with
less impact on theless impact on the
environment.environment.

6.  Very commonly used
 They help build up beach
material by preventing
longshore drift.
 Groynes are small scale
solutions and are cheaper
than sea walls.
 Groynes reduce sediment
loss from LSD, which may
have an effect on areas
downcoast (as these areas
might get starved of
material and their beaches
get smaller).
 They have a short lifespan.
GROYNES – Wooden/concrete barriers built at
right angles to the beach.

7.  Vertical or sloping walls, built along the
shoreline
 Usually made of concrete.
 They concentrate wave energy and
reflect it back at the sea.
 Often controversial as they are ugly
and can be destroyed eventually.
 Waves scour at the bases of the walls
& eventually undermine them, causing
failure. As a result, seawalls only
provide temporary protection before
needing replacement.
 They are expensive.
 The wall receives maximum impact
which weakens the structure.
SEA WALLSSEA WALLS

8.  Designed to reduce the energy of the waves
 The structures absorb the
energy of the waves
before they reach the
cliffs. This method
prevents wave scour.
 Allow sediment to pass
through them, which
means that LSD is not
stopped.
 They are also very
cheap, but they do need
to be replaced quite
often & can be regarded
as ugly.
REVETMENTSREVETMENTS

9. • Large boulders that are lain
against the cliff / on the beach like
a wall
• They are permeable structures
so allow water through but they
are able to dissipate wave
energy by absorbing the
impact of the waves.
• Boulders are much cheaper than
sea walls & are longer lasting.
• However, some consider them
ugly & can reduce the
recreational value of the beach.
• They can also act as groynes &
can prevent LSD
Rock Armour (Rip-Rap)

10. • Similar to the Rip-rap method of
protection (they dissipate wave
energy etc).
• However, gabions use smaller
rocks and are encased in a
wire mesh
• Potential problems arise when
the wire mesh breaks (risk of
injury) and could also say that
they are pretty ugly.
• Gabions may not last for a long
period of time (5-10 years)
GABIONSGABIONS

12.  Replacement of sand/pebbles on
eroding beaches.
 Beaches are the best natural
protection against erosion as they
dissipate wave energy
 The best example is the nourishment
of beaches at Miami Beach where
17.7 million m³ of sediment was built
up
 The problem with beach nourishment
is that one severe storm event may
remove vast amounts of the
expensive sediment.
 Short life span
Beach Nourishment / ReplenishmentBeach Nourishment / Replenishment

13. Beach reshaping.
•Sand dunes and cliffs are a
natural sea defence.
•They dissipate wave energy
and protect the area behind
from flooding.
•They are stabilised by
fences or by planting grasses
to hold the sand and rocks
together.
•This is cheap and effective
but easily damaged by people
if not maintained and have a
short life span

14. MANAGED RETREATMANAGED RETREAT
•This is where in certain areas, the
sea is allowed to reclaim (flood)
the land that was once covered by
the sea.
•This often means that farmland is
lost, but the pressure of floods are
reduced because it creates salt
marshes that can be flooded and
can absorb the energy.
•A natural and long-term sustainable
solution.
•Does require compensation for land
that is lost.

15. Sea Wall
Do nothing –
managed retreat
Beach
Renourishment
Groynes
Cliff reshaping
Beach
Renourishment
Rock Armour

16. Method How does it work? Advantages Disadvantages
Groynes
Sea Wall
Revetments
Rock Armour
Gabions
Beach
renourishment
Beach reshaping
Managed Retreat

17. Dorset tripDorset trip
• Working in groups of 3
• Look through the booklet of activities
• Timeline for the day (important = meet in
North carpark @ 0745, return @ 1700)
• What to bring?