Flashcards in How can coastlines be managed to meet the needs of all players Deck (34)
what are some economic, social and environmental costs of coastal recession?
economic loss- loss of property in the form of homes, businesses and farmland. These are relatively easy to quantify
social loss- costs of relocation and loss of livelihood/jobs (which can be quantified) but also include impact on health such as stress and worry (which are much harder to quantify.
environmental losses- loss of coastal ecosystems and habitats. These are almost impossible to quantify financially but are likely to be small.
what is meant by amenity value?
the value in cultural, human wellbeing and economic terms of an attractive environment that people enjoy using.
why are economic losses due to erosion small?
-erosion happens slowly with a small number of properties affected over a long period of time
-property that is at risk loses its value long before it is destroyed by erosion, because potential buyers recognise the risk
-areas of high-density population, especially towns and villages, tend to be protected by coastal defences
for people living on the coast, erosion means...
-falling property values, as the fate for eventual loss approaches
-an inability to sell their property because the possibility of loss by erosion is too great
-an inability to ensure against their loss (coastal erosion isn't covered)
-the loss of their major asset, and facing the costs of getting a new home
-an increasingly unuttered environment scarred by collapsing cliffs, failing sea defences and blocked roads and paths
In the UK, what is available for people who's homes have been lost to coastal erosion?
'Coastal Change Pathfinder'
-covers the cost of property demolition and site restoration
-provide up to £1000 in relocation expenses such as removal vans and storage
-provide up to £200 in hardship expenses
-have 'roll back' policies giving people fast-tracked planning approval to build a new home somewhere else
what are some social and economic impacts of coastal storm surges in developed and developing countries?
USA hurricane sandy:
$- $70 billion in damage, 6 million lost power, 350,000 homes damaged or destroyed
:(- 71 deaths
Philippines typhoon Haiyan:
$- damage of $2 billion
:(- at least 6,300 deaths and 30,000 injured
what are some places most at risk from coastal flooding? why are they all at risk
low lying land:
1. coral reefs which act as a natural coastal defence are being destroyed by global warming
2. water supply is limited and at risk of salt-water incursion
3. they have small/narrow economies based on tourism and fishing, which are easily disrupted
4. they have a high population density meaning there's a very limited space, so not opportunity for relocation.
what are meant by environmental refugees?
communities forced to abandon their homes because of natural processes including sudden ones such as landslides or gradual ones such as erosion and rise in sea-levels.
what is hard engineering?
man-made structures that aim to directly stop physical processes (such as erosion or mass movement) or alter them to protect the coast (encouraging deposition)
what are some general costs and benefits of hard engineering?
+ obvious to at-risk people that something is being done to protect them
+a 'one-off' solution that could protect a stretch of coast for decade
-costs are usually high and there are often maintenance costs (groins £200, sea wall £3,000-10,000, rip rap £1300-6000)
-coastlines are made visually unattractive and needs of coastal ecosystems are often over-looked
-defence built in one place frequently have adverse effects further along the coast.
what is rip-rap and what does it do/what are its impacts?
what: large igneous or metamorphic rock boulders, weighing several tonnes
purpose: break up and dissipate waves energy (often used ay the base of a sea wall to protect them from undercutting and scour)
impacts: reduced wave energy sediment deposition between rocks may become vegetation over time
what are offshore breakwaters and what do they do/what are their impacts?
what: large igneous or metamorphic rocks weighing several tonnes
purpose: forces waves to break offshore, rather than at the coast, reducing wave energy and erosive force.
impacts: deposition encouraged between breakwater and beaches- can interfere with LSD
what are sea walls and what do they do/what are their impacts?
what: concrete with steel reinforcement and deep piled foundations; can have a stepped and or 'bullnose' profile
purpose: a physical barrier against erosion. they often also act as flood barriers. modern sea walls are designed to dissipate rather than reflect wave energy
impacts: destruction of the natural cliff face and foreshore environment if reflective, can reduce beach volume.
what are revetments and what do they do/what are their impacts?
what: stone, timber or interlocking concrete, sloping structures which are permeable.
purpose: to absorb wave energy and reduce swash distance by encouraging infiltration. reduce erosion on dune faces and mud banks
impact: reduced wave power can encourage deposition and may become vegetated.
what are groins and what do they do/ what are their impacts?
what: vertical stone or timber 'fences' built at 90° to the coast, spaced alongtheu beach.
purpose: to prevent LSD movement of sediment and encourage deposition building a wider, higher beach
impact: prevention of longshore drift, deposition and beach accretion, sediment starvation and increase in erosion down drift, terminal groin syndrome.
what is soft engineering?
an alternative to hard engineering that attempts to work with natural physical systems and processes to reduce the coastal erosion and flood threat. It is usually less obvious and intrusive and may be cheaper in the long term.
what are three key soft engineering strategies?
-cliff regrading and drainage
describe beach nourishment and the costs and issues
what it is: artificial replenishment of beach sediment to replace sediment lost by erosion, to enlarge the beach so that it dissipates wave energy and reduces wave erosion and increases the amenity value of the beach.
costs and issues: typically costs £2 million per km and ongoing costs are high and sediment must not be sourced from elsewhere in the local sediment cell
describe cliff regrading and drainage and the costs and issues
what is is: cliff slope angles reduce to increase stability and revegetated to reduce surface erosion. In-cliff drainage reduces pore-water pressure and mass movement risk.
costs and issues: costs of £1 million per 100m are common. can be disrupted during construction
describe dune stabilisation and the costs and issues
what is it: fences are used to reduce wind speeds across the dunes, which are then replanted with marram and lyme grass to stabilise the surface. This reduces erosion by wind and water.
costs and issues: dune fencing costs £400-2000 per 100m and replanting dunes about £1000 per 100m. this means that working to maintain natural sand dunes can be very cost-effective in the long term.
what does sustainable coastal management mean?
managing the wider coastal zone in terms of people and their economic livelihood, social and cultural well-being, safety from coastal hazards, as well as minimising environmental and ecological impacts.
what are 5 aspects to coastal management?
1. monitoring coastal change and adapting to unexpected trends
2. educating communities to understand why change is needed and how to adapt
3. adapting to sea level rise by relocating, alternative building methods and water supplies
4. creating alternative livelihoods before existing ones are lost into the sea
5. managing flood and erosion risks where possible, or relocating to safer areas.
what are some reasons adopting to sustainable management may lead to conflict?
-coastal management resources may have to be used less in order to protect them- so some people may loose income
-relocation may be needed where engineering solutions are too costly or not technically feasible
-some erosion and/or flooding will always occur, as engineering schemes cannot protect against all threats
-future trends, such as sea level rise, may change, creating uncertainty and the need to change a plan.
describe what is meant by conflict in the context of coastal management
the disagreement over how the coast should be protected from threats and which areas should be protected. often conflict exists between different stakeholders, such as residents versus the local council
what is a holistic approach increasingly used to manage the coast?
ICZM (integrated coastal zone management)
coastal management planning over the long term, involving all stakeholders, working with natural processes and using 'adaptive management' i.e changing plans as threats change
the ICZM work with littoral cells
what is meant by the littoral zone?
a series of sub-zones to represent the features of the wider coastline. include: offshore, nearshore, foreshore and back shore. the zone reaches dynamic equilibrium where there's a balance between inputs and outputs
in the UK, what is coastal management overseen by?
DEFRA (the government department for environment, food and rural affairs)
what are the four policies for coastal management and describe them
1. NO ACTIVE INTERVENTION: no investment in defending against flood or erosion. the coast is allowed to erode inward or flood
2. STRATEGIC REALIGNMENT: allow the coast to recede but manage the process by directing it in certain areas
3. HOLD THE LINE: build or maintain coastal defence so that the position of the shoreline remains the same.
4. ADVANCE THE LINE: build new coastal defences on the seaward side of the coast (often involves land reclamation).
deciding on which policy coastal management policy to use depends on a number of different factors such as...
-the economic value of the assets being protected
-the technical feasibility of the engineering solutions
-the cultural and ecological value of land
-pressure from communities
-social value of communities that have existed for centuries.