C -> 4.1 - 4.6 Flashcards
Sea wall/ groynes/ recurved sea wall
Effective – land protected, land stable
Income will be possible , e.g. From tourism
Expensive, millions of pounds
Need maintenance continually
Visual impact is poor – can harm tourism
Interfere with natural processes, e.g. LSD can prevent beach formation downdrift
Why hasn’t it worked:
what processes have been disrupted?
Leslie’s Pier – built in 1760, rebuilt 1895
by diffracting incoming waves, it’s created a low-energy zone in the shadow
Therefore, waves attack centre of the bay
Longshore drift from centre to East, removing sand
Rip current takes sediment out into deeper water
Beach is deprived of sandy sediment
Lyme Regis Key Info: benefits
- 5000 residents + 15k tourists
- Cobb Hill - slipping down hill\
- Proposed cost 30 million
- Beach material from France, Norwegian rock armour + 1000 deep bored pins to prevent landslides
- 2000 more people visited, beach kept in place and improved ramp access
Expansion of pier
led to it acting like a groyne, trapping sediment to the left, so the bay receives minimal sediment from LSD
Beach nourishment can be
good for low energy coastlines as the beach would otherwise get eroded away.
- Artificial drainage above the impermeable layer, to get water out of the cliff - increasing its stability by reducing pore pressure and decreasing likelihood of mass movement
- sand dunes act as a natural barrier (buffer zone)
Beach Nourishment:
artificially replenishing the sediment to replace that lost by erosion/LSD. Often used to enlarge beach (which attracts tourists and dissipates wave energy further from backshore). Typical cost of £2million per km2 and need to be replaced every few years. Issue if dredged from within sediment cell as removes material from system.
Cliff Stabilisation & Drainage:
regrading the cliff to a lower angle of rest provides stability – which can be further supported by hard engineering at the base (e.g. Rip-Rap/Revetments etc.). Adding vegetation helps to trap and stabilises any unconsolidated sediment. In cliff-drainage reduces pore-water pressures and thus stress on cliff line much quicker.
Dune Stabilisation:
combined low-impact, low-cost approach of stabilising bare sand with old trees and fencing, replanting marram grass (pioneer species), adding boardwalks to reduce trampling and educating tourists with info boards.
Other Bioprotection Methods:
- Planting Mangrove forests to offer protection against storm surges
- Ecological enhancement of hard engineering by encouraging species to grow on them
- Adding grooves, holes and natural pools into Shaldon Seawall in Devon, to encourage barnacles and limpets to grow, thereby increasing biodiversity.
Intertidal zone
Also known as foreshore or seashore, is the area above water level at low tide and underwater at high tide
What should we do instead of flood defences
Flood alleviation, as river, estuarine and coastal flooding can be reduced (alleviated) when catchments, rivers and coastal zones are managed to work with nature. Examples like restoring trees in river catchments, or conserving coral reefs
How are salt marshes so good
Examples of bio geomorphologixal systems, exist during the interplay between sedimentation and plant growth, they buffer low lying coastal areas from waves and provide space for flood water
Is there a place still for hard engineering
Yes - big cities such as London require hard engineering such as flood walls to stop strong tides
How does ecological enhancement work
Altering designs of hard coastal structures to encourage more species to grow on them, like drilling holes for limpets, or making grooves in concrete to attract barnacles.
How do bioprotective buffers work
Bio protection of the hard rock from weathering eg. For barnacles - act as thermal blankets and reduce temperature extremes, cutting down on mechanical weathering, a,so act as physical barrier to salts, reducing amount of salt for chemical and mechanics, weathering
Integrated coastal zone management (ICZM):
- ICZM idea introduced at Rio Earth Summit in 1992
- Entire coastal zone is managed across multiple littoral (sediment) cells (Holistically), bringing together all kinds of decision makers at different levels of government (Local to International).
- Emphasises co-operation between ALL stakeholders so that everyone benefits over the long term (Sustainably).
Issues with ICZM?
Part 2
- maybe too zoomed out - top down tool - what about individual voice
- varied geopolitical situation across meditteranean makes collab more complex - Israel recognition
- varying levels of economic development - NA vs SE
- lack of funding + commitment
- Mediterranean ICZM Protocol was ratified by the European Commission (EC)
- came into force in 24th March 2011 – making joint commitment legally binding by EU law!
- 46,000km of coastline (19% already occupied by tourist complexes, road networks and related infrastructures)
- Growing development means profound transformations
- Regions varied geopolitics make situation more complex.
