coastal systems -coastal management (hard engineering strategies) Flashcards
(21 cards)
what is coastal mangement?
.human intervention in coastal landscapes
what are the 3 aims of coastal management?
.provide protection against, and mitigate the impacts of, coastal erosion
.provide defense against, and mitigate the impacts of, flooding
.protect coastal habitats and ecosystems
what are the 2 main methods of coastal management?
.soft engineering strategies
.hard engineering strategies
what is a hard engineering strategy?
.more traditional approach that works against natural processes
.involves the building of structures and were very common up to 1990s
why is human intervention needed?
.50% the world’s population lives within 60km of a coast
.75% of all large cities are on the coasts
.erosion, flooding and habitat destruction are increasing in many areas
can we protect everywhere?
.protecting the whole coastline is not an option, it is both unaffordable and would have huge consequences for coastal systems, as material eroded from one part of the coast provides sediment that protects another area of the coast
who is response for funding coastal protection?
.in England and Wales, the Environment Agency is responsible for funding coastal protection
what happens before a project is given the go ahead?
.a cost benefit analysis
.when the financial cost of a strategy eg -building costs, maintenance is compared to the expected benefits in terms of savings eg -housing protected, savings inrelocating people
what was the traditional approach to coastal management?
.before the 1990’s, human intervention involved taking direct action along relatively short sections of coastline to either stop or slow down erosion or reduce the risk of coastal flooding -including both soft and hard but mainly hard
what are the sustainable approaches?
.become the preferred approach in recent decades as our understanding of coastal systems has increased
.these approaches are more holistic, take a longer-term view and typically focus on a sediment cell .the aim is to consider the entire coastal zone and to achieve a balance between natural processes and human needs
what are the 5 hard engineering strategies?
.groynes
.sea walls
.rock armour
.revetments
.offshore waterbreak
what are groynes?
.timber or rock structures built at right angles to the coast
.they trap sediment from being moved along the coast by LSD
what are the positives and negatives to groynes?
.positives -work with natural processes to build up the beach
.positives -not too expensive
.negatives -starve beaches further along the coast of fresh sediment -leads to increased erosion elsewhere
what are sea walls?
.stone or concrete walls at the foot of a cliff or top of a beach
.have a curved face to reflect waves back into the sea
what are the positives and negatives to sea walls?
.positives -effective prevention of erosion
.negatives -reflect wave energy rather than absorb it
.negatives -very expense to build and maintain
what is rock armour?
.large rocks placed at the foot of a cliff or top of a beach
.forms a permeable barrier to the sea, breaking up waves
what are the positives and negatives to rock amour?
.positives -relatively cheap and easy to construct and maintain
.negatives -dangerous for people clambering over them
.negatives -rocks are usually not local so can look out of place with local geology
what are revetments?
.sloping wooden concrete or rock structured place at the foot of a cliff or at the top of a beach
.break waves energy up
what are the positives and negatives to revetments?
.positives -relatively inexpensive to build
.negatives -instructive and unnatural looking
.negatives -need high levels of maintenance
what are offshore breakwaters?
.a partly submerged rock barrier, designed to break up the waves before they reach the coast
what are positives and negatives to offshore breakwater?
.positives -effective permeable barrier
.negatives -visually unappealing
