Geography CP&L: Coastal Management Flashcards
Hard Engineering
GROYNES - Advantages
(The repeated zigzag of swash and backwash piles sediment up against the windward side of each groyne)
Cost: £150 - 250 per metre
Highly effective in a local context, such as in the maintenance of holiday beaches. (Should the beach become too uneven, this can be redistributed between the GROYNES, using earth-moving equipment, during the low season).
Hard Engineering
GROYNES - Disadvantage
(The repeated zigzag of swash and backwash piles sediment up against the windward side of each groyne)
Whilst relatively cost -effective to construct, they do require ongoing maintenance. Aesthetically questionable, although they have acquired a visual acceptance through longevity rather than design. The need for expensive hardwood timbers raises the question of sustainability.
Hard Engineering
GROYNES - How Sustainable is it?
(The repeated zigzag of swash and backwash piles sediment up against the windward side of each groyne)
- Sustainable - wooden
- Structurally are environmentally friendly
- Cheep
- Can negatively impact the beach lower down the coast.
Hard Engineering
SEA WALLS - Advantage
(Massive barriers both absorb and reflect wave energy. Recurved wall design turn waves back on themselves)
Cost: £3,000 - 10,000
- Effective property defence in high-risk locations e.g. Robin Hood’s BAy, North Yorkshire
Hard Engineering
SEA WALLS - Disadvantage
(Massive barriers both absorb and reflect wave energy. Recurved wall design turn waves back on themselves)
Very effective to both build and maintain. By deflecting waves, rather than dissipating their energy, concrete sea walls most notably, whether recurved it felt faced, are prone to relatively rapid erosion.
Hard Engineering
SEA WALLS - How Sustainable is it?
(Massive barriers both absorb and reflect wave energy. Recurved wall design turn waves back on themselves)
- Generally have a long life expectancy (20 - 50 years)
- Expensive
- Not appealing to look at
Hard Engineering
RIP RAP (ROCK ARMOUR) - Advantage
(Metal cages filled with beach cobbles and pebbles both reflect and absorb wave energy)
Cost: £1,300 - 6,000 per metre
- Relatively cheaper than concrete structures
Hard Engineering
RIP RAP (ROCK ARMOUR) - Disadvantage
(Metal cages filled with beach cobbles and pebbles both reflect and absorb wave energy)
- Rock armour traps flotsam and jetsam leading to both smell and rat infestations.
- Presents a potential public safety hazard as a tripping and trapping hazard
Hard Engineering
RIP RAP (ROCK ARMOUR) - How Sustainable it is?
(Metal cages filled with beach cobbles and pebbles both reflect and absorb wave energy)
- Not environmentally Sustainable - requires a lot of trucks to transport, emitting large levels of air pollution.
- Rip RAp retains heat and can increase water temperature which leads to thermal pollution, harming aquatic life.
Hard Engineering
GABIONS - Advantage
(Wires cages filled with rocks that can be built up to support a cliff or provide a buffer against the sea)
Cost: £500 per metre
- Cheap to produce and flexible in the final design
- Can improve drainage of cliffs
- Will eventually become vegetated and merge into the landscape
Hard Engineering
GABIONS - Disadvantage
(Wires cages filled with rocks that can be built up to support a cliff or provide a buffer against the sea)
- For a while they look very unattractive
- Cages NLT last 5 - 10 years before they rust
Hard Engineering
GABIONS - How Sustainable it is?
(Wires cages filled with rocks that can be built up to support a cliff or provide a buffer against the sea)
- Gabions are made of sustainable material and can last for many years.
- Require less energy to manufacture and distribute resulting in reduction of carbon and energy footprint.
- Cost effective
Hard Engineering
REVETMENTS - Advantage
(Sloping structure built on embankments or shorelines, along the base of cliffs)
- Effective property defence in high risk locations e.g. Robin Hood’s Bay, North Yorkshire
Hard Engineering
REVETMENTS - Disadvantage
(Sloping structure built on embankments or shorelines, along the base of cliffs)
- Very expensive to both build and maintain. By deflect waves, rather than dissipating their energy, concrete sea walls most notably, whether recurred or flat faced are prone to relatively rapid erosion
Hard Engineering
REVETMENTS - How sustainable it is?
(Sloping structure built on embankments or shorelines, along the base of cliffs)
- Argue that sloping rock revetments create less environmental impact then vertical concrete sea walls, as absorb waves.
- Not pleasing to look at
- Block of beach
Hard Engineering
OFFSHORE BREAKWATER - Advantage
(A coastal structure ~ usually a rock and rubble mound structure ~ parallel or close to the coast)
Cost: £1,000 per metre
- Very effective at protein coastline in the short term compared to some long term soft engineering methods as they are effective immediately
Hard Engineering
OFFSHORE BREAKWATER - Disadvantage
(A coastal structure ~ usually a rock and rubble mound structure ~ parallel or close to the coast)
- They are intrusive
- Can issues elsewhere at other areas along the coast line
Hard Engineering
OFFSHORE BREAKWATER - How sustainable it is?
(A coastal structure ~ usually a rock and rubble mound structure ~ parallel or close to the coast)
- Eco-friendly breakwaters do double duty as welcoming homes for marine life
- Unintended impact on sediment distribution
Soft Engineering
BEACH NOURISHMENT AND REPROFILING - Advantage
(Sand, shingle and coastal sediments are added to the beach from elsewhere)
Cost: £3 per metre
- Aesthetically pleasing. Arguably essential in supporting the tourist industry
Soft Engineering
BEACH NOURISHMENT AND REPROFILING - Disadvantage
(Sand, shingle and coastal sediments are added to the beach from elsewhere)
- As such scheme requires expensive annual replenishment to compensate for continued erosion and drifting
Soft Engineering
BEACH NOURISHMENT AND REPROFILING - How sustainable it is?
(Sand, shingle and coastal sediments are added to the beach from elsewhere)
- Does not end erosion
- It only provides additional sediments on which erosion will continue
- High cost over time
Soft Engineering
DUNE REGENERATION - Advantage
(Action to build-up dunes and increase vegetation on dune strengthen)
Cost: £3 per metre
- Maintains natural appearance of coastline provides habitat
- Absorbs wave energy
Soft Engineering
DUNE REGENERATION - Disadvantage
(Action to build-up dunes and increase vegetation on dune strengthen)
- Can be easily damaged by storm waves
- Areas have to be zoned off from public while it grows
- Protection is limited to small areas
Soft Engineering
DUNE REGENERATION - How sustainable it is?
(Action to build-up dunes and increase vegetation on dune strengthen)
Ensures a sustainable balance between development and the coastal environmental
