coastal management - lyme regis Flashcards
coastal management benefits
maintains balance between the forces of nature and demands of people
protects from erosion and flooding
coastal management costs
coastal defenses becoming more expensive
increasing costs may outweigh benefits
less common because are expensive and have high maintenance costs, interfere with natural coastal processes and can cause destructive knock-on effects elsewhere - for example, altering wave patterns along coast leading to new problems (e.g. cliff collapse), looks unnatural
hard engineering
using artificial structures to control natural processes
groynes
timber/rock structures built out to sea from the coast, trap sediment moved by longshore drift, enlarges beach which acts as a buffer to reduce wave damage
£150000 for every 200m
groynes advanatges
creates wider beach, popular with tourists
provides useful structures for people interested in fishing
less expensive than other methods
groynes disadvantages
interrupts longshore drift so starves beaches further along the coast, leading to increased rates of erosion elsewhere, problem shifted rather than solved
unnatural - can be viewed as unattractive
rock armour
piles of large boulders dumped at foot of cliff, forces waves to break, absorbs energy and protects cliffs
£200000 per 100m
rock armour advantages
relatively cheap and easy to maintain
can provide interest to the coast
often used for fishing
rock armour disadvantages
rocks are usually from other parts of coastline or even abroad
can be expensive to transport
often do not fit in with the local geology
can be very obtrusive
gabions
wire cages filled with rocks that can be built up to support a cliff or provide a buffer against the sea
up to £50000 per 100m
gabions advantages
cheap to produce and flexible in the final design
can improve drainage of cliffs
can eventually become vegetated and merge into the landscape
gabions disadvantages
for a while they look very unattractive
cages only last 5-10 years before they rust
sea wall
concrete or rock barrier against the sea, placed at the foot of cliffs or at the top of beach, often has curved face to reflect the waves back into sea
£5000-£10000 per metre
sea wall advanatges
effective at stopping the sea
often has a walkway or promenade for people to walk alongs
sea wall disadvantages
can look obtrusive and unnatural
very expensive and high maintenance costs
soft engineering
try to work with natural coastal processes, tend to be cheaper than hard engineering but may require more maintenance, generally more sustainable and are often preferred option for coastal management now
beach nourishment
addition of sand or shingle to an existing beach to make it higher or wider, sediment usually obtained offshore locally to it blends in with existing beach material
up to £500000 per 100m
beach nourishment advantages
blends in with existing beach
increases tourist potential by creating a bigger beach
beach nourishment disadvantages
needs constant maintenance unless structures there to retain beach
expensive
dune regeneration
marram grass planted to stabilise dunes (effective buffers) and help them develop, fences used to keep people off newly planted grass
£200-£2000 per 100m
dune regeneration advantages
maintains natural coastal environment that is popular with people and wildlife
relatively cheap
dune regeneration disadvantages
time-consuming to plant marram grass and fence areas off
people don’t always respond well to being prohibited from accessing planted areas
can be damaged by storms
dune fencing
constructed on sandy beach along seaward face of existing dunes to encourage new dune formation - help to protect existing dunes
£400-£2000 per 100m
dune fencing advantages
minimal impact on natural systems
can control public access to protect other ecosystems
dune fencing disadvantages
can be unsightly especially if fences become broken
regular maintenance needed especially after storms
managed retreat
deliberate policy of allowing the sea to flood or erode an area of relatively low-value land, form of soft engineering
doesn’t need large sums of money, becoming increasingly popular as sea levels rise
coastal monitoring, management and adaptation
no active intervention - do nothing, no current plans to build defences
hold the line - maintain the current defences
advance the line - increase coastal defences to extend coastline out to sea
managed retreat
driven by costs and benefits, only areas of high value land protected by costly engineering
lyme regis
small coastal town on south coast of england, heart of the world heritage site known as Jurassic Coast, famous for fossils, popular tourist destination
reasons for management in lyme regis
much of the town built on unstable cliffs
coastline is eroding more rapidly than any in europe due to powerful waves from south west, many properties destroyed or damaged, sea walls have been breached many times
coastal management in lyme regis
new sea wall and promenade constructed to east of mouth of river lym, wide sand and shingle beach, extension of rock armour, constructed new 390m sea wall in front of existing wall
lyme regis coastal management positives
new beaches have increased visitor numbers and sea front businesses are thriving
new defences have stood up to recent stormy winters
harbour is now better protected, benefitting boat owners and fishermen
lyme regis coastal management negatives
increased visitor numbers led to conflicts with some local people who think traffic congestion and litter have increased
some people think new defences have spoilt natural coastal landscape
new sea wall may interfere with coastal processes and affect neighbouring stretches of coastline, causing conflicts
stabilising cliffs will prevent landslips that may reveal important fossils - potential conflict
