Coastal management Flashcards
Coasts
What is the aim of coastal management?
The aim of coastal management is to protect homes, businesses and the environment from erosion and flooding to mitigate the potential social, economic and environmental impacts.
What is cost-benefit analysis?
Cost-benefit analysis is a decision-making tool used to evaluate the economic validity of projects by comparing the costs and benefits.
What are the four options for coastal management?
1= Hold the line
2= Advance the line
3= Do nothing
4= Managed retreat
What does it mean if a coastline ‘holds the line’?
This is where the existing coastal defences are maintained.
What does it mean if a coastline ‘advances the line’?
This is where new coastal defences are built further out to sea than the existing line of defence.
What does it mean if a coastline ‘does nothing’?
This is where no coastal defences are built, and erosion and flooding is managed as it happens.
What does it mean if a coastline uses ‘managed retreat’?
This is where the shoreline is allowed to move, but managed so that it causes less damage.
What is hard engineering?
Hard engineering strategies involve built structures to control natural processes.
List as many hard engineering strategies as you can.
1= Sea wall
2= Revetment
3= Gabions
4= Riprap
5= Groynes
6= Breakwaters
7= Earth bank
8= Tidal barrier
9= Tidal barrage
A ___ ____ reflects waves back out to sea, preventing erosion of the coast. It also acts as a ________ to prevent ________.
sea wall
barrier
flooding
What are benefits/drawbacks of a sea wall?
Sea walls are expensive to build and maintain, and create a strong backwash which can erode the underside of the wall.
__________ are slanted structures built at the foot of cliffs. They can be made from concrete, wood or rocks. Waves ______ against them and ______ wave _______ and prevent cliff ________.
Revetments
break
absorb
energy
erosion
What are benefits/drawbacks of revetment?
Revetments are expensive to build, but reletively cheap to maintain. They also create a strong backwash.
________ are rock-filled cages. A wall of them is usually built at the foot of cliffs. They _______ _______ and reduce ________.
Gabions
absorb
energy
erosion
What are benefits/drawbacks of gabions?
Gabions are cheap to install, however they are not aesthetically pleasing.
Boulders piled up along the coast is called _______ or ______ _______. They _______ wave _______ and reduce _______.
riprap
rock armour
absorb
energy
erosion
What are benefits/drawbacks of riprap/rock armour?
They are fairly cheap to make, but may shift during storms making them ineffective.
_______ are fences built at right angles to the coast. They trap material transported by ___________ _____, creating wider _______, slowing down _______ and giving greater protection from _______ and _______.
Groynes
longshore drift
beaches
waves
flooding
erosion
What are benefits/drawbacks of groynes?
Groynes are quite cheap to install, but they starve beaches further down of sediment, leading to greater erosion and flooding in other areas.
An _____ _____ is a mound of earth that acts as a barrier to prevent flooding.
earth bank
What are benefits/drawbacks of an earth bank?
They are quite expensive and can be damaged in storms.
______ _________ are built across river estuaries. They contain retractable _________ that can be raised to prevent _________ from storm surges.
Tidal barriers
floodgates
flooding
What are benefits/drawbacks of tidal barriers?
They are very expensive. like, VERY expensive. Could be hundreds of millions of pounds for a large one.
What is soft engineering?
Soft engineering is coastal and river management techniques that work with natural processes and ecosystems rather than imposing artificial structures to reduce erosion and flooding.
What is beach nourishment?
Beach nourishment is where sand and shingle are added to beaches from elsewhere. This creates wide beaches, which reduces erosion.
What is a drawback of beach nourishment?
Beach nourishment can disrupt the ecosystem due to organisms in the sediment being foreign to the beach.
What is beach stabilisation?
Beach stabilisation is where the slop angle is reduced and vegetation is planted. It stabilises the beach as well as widening the beach.
What is dune regeneration?
Dune regeneration is where sand dunes are either creted or restored by either nourishment or stabilisation of the sand. Dunes provide a barrier between land and sea and absorb wave energy reducing erosion.
Why is land use managment important when using soft engineering strategies?
Land use management is important for dune regeneration because the vegetation needs to stabilise, and it is very vunerable and can be easilly trampled on. The main strategy to prevent this is fencing off areas.
How can creating marshland be used as soft engineering?
Creating marshland as the vegetation stabilises the sediment, and helps to reduce the speed of the waves, reducing their erosive power and how far they reach inland.
What is coastal realignment / managed retreat?
Coastal realignment / managed retreat involves breaching an existing defence and allowing the sea to flood the land behind. Over time, vegetation will colonise the land and it will become marshland.
What must management strategies be?
Management strategies must be sustainable - so that they don’t cause too much damage to the environment or peoples homes now or for the future.
What is the drawbacks to hard engineering strategies?
Hard engineering strategies are often very expensive and disrupts natural processes.
What are the benefits of soft engineering strategies?
Soft engineering strategies tend to be cheaper and require less time and money to maintain. They are designed to integrate into the environment.
What is a Shoreline Management Plan (SMP)?
This is where the coastline is split into stretches by sediment cells, and a plan is devised for how to manage each one with the aim of protecting important sites. It may be chosen to hold, advance, retreat or do nothing.
What is Integrated Coastal Zone Management (ICZM)?
The ICZM considers all elements of the coastal system (land, water, people, economy) when coming up with a management strategy.
How is an ICZM integrated?
1= Environment is viewed as a whole
2= Different uses are considered
3= Local, regional and national levels
4= It is dynamic, decisions are reevaluated if need be.
Give an example of a place where sea level rises are having damaging impacts.
At the muni coastal lagoon, Ghana. It is usually intermittently open to the ocean, but recently has stayed open for prolonged periods of time due to human action. It has led to rapid erosionand strained the local ecosystem.
Happisburgh has a population of around _____ people. Between 1600 and 1850, over ____m of land (and a whole village) have been lost to the sea. It is the fastest eroding coastline in the world, at a rate of __m a year.
1400
250m
2m
Happisburgh- In 1950, ________ were constructed and sea defences were built in _____. However, in 1990, ____m of revetment was damaged in a storm, leading to ___ properties being lost. In 2002, _____ tonnes of _____ ______ was placed at the foot of the cliff which was realigned in ____.
groynes
1959
300m
six
4,000
rock armour
2015
