3.1.3.4 Coastal Management Flashcards
what is the aim of coastal management?
to protect homes, business and the environment from the risk of erosion and flooding
how are places chosen to be protected?
cost-benefit analysis
what are the four options for coastal management?
Hold the line
Advance the Line
Do nothing
Manage retreat
what are different hard engineering strategies
sea wall revetments gabions rip rap groynes tidal barrier
how do sea walls operate?
reflect wave energy back to sea, preventing erosion of the coast
acts as a flood barrier too
how do revetments operate?
slanted structures at the foot of cliffs to stop cliff erosion as they absorb and break wave energy
what are gabions and what do they do?
cages of rocks that absorb wave energy to reduce erosion
what is rip rap and what does it do?
boulders piled against the coastline to absorb wave energy and reduce the rates of erosion
what are groynes and what do they do
fences built at right angles to the coast
they trap material transported by longshore drift
which creates wider beaches which slow waves
what are tidal barriers and what do they do?
built across river estuaries
contain retractable flood gates that can be prevented to prevent flooding from storm surges
cost / disadvantage of sea walls
£6000/m
creates strong back wash which erodes under the wall
needs consistent maintenance
ugly
cost / disadvantage of revetments
£4500/m
less durable than sea wall
cost / disadvantage of gabions
cheap but ugly
cost / disadvantage of rip rap
£1000/m
still lets water through so some erosion still takes place
easily moved by high energy waves
cost / disadvantage of groynes
£1000/m
cause erosion to increase further down the coastline
last up to 40 years
cost / disadvantage of tidal barriers
VERY expensive
Thames barrier total construction cost was £534 million which is equivalent to £1.6 billion at 2016 prices
what is hard engineering?
the building of entirely artificial structures to reduce or stop the impact of coastal processes
what is soft engineering
strategies that work with natural features and processes
examples of soft engineering
beach replenishment
managed retreat
cliff regrading and drainage
dune stabilisation
what is bleach replenishment
sand is replaced along the beach
advantages and disadvantages of beach replenishment
A - makes the beach more effective at dispersing wave energy
A - attractive
D - doesn’t prevent longshore drift so has to be done repeatedly
how much does beach replenishment cost
£300/m
what is managed retreat
allowing the coast to reclaim the land
advantages and disadvantages of managed retreat
A - allows more wetland habitats to form, natural and cheap
D - socially unfair for locals who lose land
what is cliff regrading and drainage
reducing the angle of a cliff to stabilise it
drains excess water
advantages and disadvantages of cliff regrading and drainage
A - prevents landslides and slumping, effective on clay and loose rocks
D - can dry the cliff out causing it to crumble, some homes on the cliff may have to be destroyed
what is dune stabilisation
planting durable vegetation with solid root system to stabilise dunes because they act like a barrier between land and sea
advantages and disadvantages of dune stabilisation
A - maintains natural coastal environment, cheap and sustainable
D - time consuming, can be eroded if mistreated by the public
why must coastal management be sustainable?
so there is little damage to people’s homes and livelihoods as well as not incurring high costs
why is soft engineering more sustainable than hard?
because it is cheaper, takes less time and money to maintain.
it integrates with the natural environment and creates important habitats so can increase bio diversity of an area
lower environmental impact and lower economic costs
how can an engineering strategy be sustainable?
social - works and benefits for everyone in the present and future
economic - doesn’t create an unaffordable debt at the time of national debt
environmental - encourages wildlife to thrive and increase biodiversity
what does SMP stand for?
shoreline management plan
what does ICZM stand for?
integrated coastal management plan
what do SMP’s do?
create a plan for each sediment cell with the aim or protecting important sites without causing problems elsewhere in the cell
how many sediment cells are there in the uk?
11
what does an SMP identify?
natural processes
human activities
management decisions
what is DEFRA and does it recommend SMP’s?
Department for Environment, Food and Rural Affairs
yes for all coastlines in england and wales
what do authorities decide to do in each cell?
hold, advance or retreat the line or do nothing
what sort of reports go into an SMP>
wave and tide reports
local monitoring
aerial and lidar reports
topographic beach survey reports
what does an ICZM strive to achieve?
brings together all that use, manage and develop the coast
aims to protect the coastal zone in a very natural way whilst still allowing people to use it and develop it in different ways
how are ICZM’s intergrated in different ways?
1) the environment is viewed as a whole - the lad and the water are interdependent
2) different uses are considered e.g. fishing, idustry and tourism
3) all levels and scales of authority have an iput into the plan
how are iCZM’s dynamic strategies?
because they are re-evaluated if the environment or demands of the area change
