Karteikarten
Coastal Management
Karten in diesem Stapel (39)
- 1Define hard engineering.Man-made structures built to control the flow of the sea and reduce flooding and erosion.
- 2Define soft-engineering.Soft engineering techniques involve working with nature to manage the coastline.
- 3What are the benefits of soft-engieering option (over hard-engineering)?Soft-engineering options work operate in coordination with natural coastal systems rather than impeding them- less impact on the environment.
Usually cheaper and requires little maintenance.
Long-lasting- sustainable - 4State the main 6 types of hard-engineering option1 Sea Wall
2 Revetments
3 Rip rap
4 Tetrapods
5 Gabions
6 Off-shore reefs - 5What is a sea wall?A solid facing to a coastal wall or cliff.
- 6How does a sea wall work?The wall absorbs and deflects wave energy back to sea. Recurved upper lip dampens down oncoming wave power
- 7What are the disadvantages of sea walls?Requires regular repair.
Quarrying at base can undermine sea wall foundations.
Expensive to construct.
Gives an artificial appearance to the coast. - 8What are revetments?Open slanted concrete or wooden facing/fence offering partial resistance but letting some seawater to pass through.
- 9What are the advatanges/disadvantages of revetments?Benefits:
1 Cheaper to construct than a sea wall.
2 Along a beach they allow beach material to be deposited behind
3 Reduce power of oncoming waves - 10What are the pitfalls of revetments?Issues:
1 Can restrict sea access from a beach
2 Unattractive
3 Can be damaged in high energy conditions
4 Require regular maintenance & repair - 11Describe what rip rap is.Massive blocks of natural rock placed in position and piled up at the base of a cliff
- 12Outline the benefits of rip rap.Requires less maintenance than a sea wall
Granite often used is barely eroded even under highest energy conditions
May look more natural than a concrete sea wall - 13What are the issues with rip rap?Expensive to extract, transport and place in position
Can impede access to a beach by visitors
Can lead to injuries climbing over - 14What are tetrapods?Moulded multi-angular concrete shapes formed on site and tipped onto beach to form interlocking components.
- 15Describe the benefits of tetrapods.Cheaper than rock armour but doing the same role by being constructed on site from liquid concrete
Effective along long stretches of coastline requiring protection - 16What are the issues with tetrapods?Less attractive than natural rock – look artificial
May protrude into sea and endanger swimmers/small craft
Almost impossible to climb over to get access to a beach - 17What are gabions?Rock-filled wire cages placed along a vulnerable coast
- 18Outline the advantages of using gabions as a coastal managment strategy?Cheaper than tetrapods but do the same thing
May look more attractive than alternatives - 19What are the issues with gabions?Wire containers may rust and be broken under high energy conditions
Require regular repair & replacement
Rodents may inhabit spaces between rocks - 20Define the term 'groynes.' how do they work?Wooden (or less often, boulder) ‘breakwaters’ at right angles to a beach extending into the sea. They are designed to capture longshore drift sediments to build up beach width and height.
- 21What are the benefits of groynes?Effective at increasing a natural barrier of beach between sea and shore
Tourism amenity as wider beaches attract more visitors
Calmer inshore water - 22Outline the issues associated with groynes.Usually made of hardwood- unsustainable.
Require maintenance and repair
Speed up downcoast erosion by robbing adjacent beaches of sand - 23Describe what an off-shore reef is and its function.Artificial sand/gravel offshore deposits designed to intercept destructive wave action. The most ‘natural’ of hard engineering techniques
- 24Outline the benefits of off-shore reefs.Create additional shore habitat
Create calmer water conditions between them and shore – benefits tourist use - 25What are the disadvantages of off-shore reefs?Vulnerable to storm conditions
Less reliable than ‘concrete/rock’ strategies
May be overwhelmed by rising sea levels - 26Why are hard engineering option not sustainable?High cost.
Protection of one area comes at a cost to other groups further along the coast.
Vunerable to:
1) Storm surges
2) Tidal surges at spring tides with accompanying low pressure systems
3) Rising sea levels - 27Outline the environmental downfalls of hard engineering stratergies.They interrupt natural coastal systems by slowing down or preventing coastal erosion meaning the input of sediment into the system is reduced.
This has implications for beach size, depositional features and transfers to neighbouring sub-systems. - 28State the main SOFT engineering options.Beach nourishment
Dune nourishment
Living shoreline bariers
Managed Retreat (coastal realignment) - 29What is beach nourishment?Replacing lost beach material from a natural store either offshore (beach rebuilding) or from downshore along a stretch of longshore drift (beach recycling).
- 30Outline the advantages of this soft engineering technique.Reproduces what natural systems would do – but at a faster rate.
Sediment is not removed from the system – just redistributed.
Low cost intervention over short term
Maintains natural shoreline without artificial intrusions - 31What are the disadvantages?Requires repetition over the year (3x/year)
Regular costs accumulate over the long-term
Can be disruptive to beaches (local amenity and tourist economy) while engineering takes place - 32What does the process of cliff stabilisation involve?Cliff stabilisation involves reducing the slope angle of the cliff and planting vegetation.
- 33Describe the process of dune regeneration.Dune regeneration involves creating or restoring sand dunes through vegetation planting, creating a barrier to absorb wave energy.
- 34How can we ensure sucessful dune regeneration.Land must be carefully managed so that any new vegetation is protected from trampling.
This may involve temporarily fencing off the dunes or providing wooden walkways. - 35What are living shoreline barriers?Planting shoreline vegetation (mangrove) or shellfish colonies (oyster reefs) to absorb wave energy.
- 36Outline the benefits of this soft management strategy.Enhances shoreline habitats
More attractive for locals and visitors
Can be modified with different species to adapt to rising sea level
Offers some protection against storm/tidal surges by absorbing the forward movement of water - 37What are the disadvantages?May be harmed by pollution events
May not adjust to rising ocean temperatures/acidity
Can be devastated by extreme storm events - 38In light of rising sea levels, what soft engineering strategy is increasingly being favoured?Redirecting flooding from coastal areas that are valued (homes, industry and key infrastructure) onto areas that have less economically important. This is achieved through ‘managed retreat’.
- 39Outline the process of managed retreat.New coastal embankments are constructed further inland on slightly higher land behind low-value shoreline
Existing embankments are breached
When higher sea levels are experienced the water floods onto the specified area
New tidal saltmarsh/mudflats develop over time, absorbing flood water and providing essential wading-bird feeding habitat
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- A level Physical Geography (Coasts Flashcards) Karteikarten am Coastal Management , erstellt von Emily Bolland-Gathercole am 21/05/2018.
- Erstellt von
- Emily Bolland-Gathercole
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