Management of Coasts Flashcards
(34 cards)
Define Hard Engineering
Making a physical change to the coastal landscape using restraint material, like concrete, boulders, wood and metal.
eyesore
Define Soft Engineering
Using natural systems for coastal defence, such as beaches, dunes and salt marshes, which can absorb and adjust to wave and tide energy.
What is a Sea Wall ?
-Their main aim is to dissipate wave energy, the recurved structure throws waves back into sea of the path of the next incoming wave, reducing its impact.
-They provide a physical barriers against flooding
What is Rock Armour ?
-Consists of large boulders placed in front of a cliff or sea wall and take full force of the waves.
-The boulders are deliberately left angular in appearance to present a large surface area to the waves and create gaps for water to filter out.
What are Gabions ?
Smaller boulders that are contained within steel wire mesh cages, each of which can be joined together to form larger structures or walls.
What are Revetments ?
Concrete or wooden structures placed across a beach or coastline to take the full force of the wave energy, preventing further erosion of the coast.
What are Groynes ?
Wooden, stone or steel breakwaters built perpendicular to the coast. They are built to control longshore drift. This could lead to less sediment being deposited along the coastline.
What is Beach Nourishment ?
Aims to replace material that has been lost through longshore drift.
What is Dune Regeneration ?
Dunes are fragile to human activity, most damage is caused by the removal of vegetation. This can loosen the sediment making the sand viable to blowouts.
-replanting venerable areas with plants such as marram grass
-afforestation
-restricting human access
-providing broad walks for humans.
What is Managed Retreat ?
Abandoning the current line of sea defence and developing the exposed land in some way, perhaps with salt marshes to reduce wave power.
-the scale of hard engineering can be reduced
-In California there are requirements that buildings must be a certain distance from the shore.
Or do nothing
What is Land-Use Management ?
If erosion and flooding is inevitable, a local authority will educate the community on how locals can still use the land at risk, for example; caravan parks, using the land for grazing.
Describe a case study of Hard Engineering in the UK
The coastal town of Morecambe has used numerous strategies.
- 1) Rock Armour / locally sourced / placed along the promenade
- 2) Groins / a million tonnes of locally sourced limestone / built in intervals along the towns coast
- 3) Repaired Seawall / cost £11million / 4km of new seawall / designed to last 100 years.
- 4) Gabions / over 500 cages filled with small limestone boulders / various locations to reinforce the coast.
Describe a Case study of Soft Engineering in the UK
The Sefton Coast, north of Liverpool, has the largest dune area in England extending over 17km
- 1) planting, used Christmas trees on the seaward edge of the dunes to trap more sand and encourage dune regeneration.
- 2) fencing off areas of sand dunes to restrict pedestrian access
- 3) wooden posts placed in front of the dunes to encourage dune regeneration.
What are the Sundarbans ?
The Sundarbars is a coastal zone occupying the world’s largest delta that extends over 10,000km sq. The Ganges, Brahmaputra and Meghan all deposit sediment into this delta. The natural climax of the Sundarbans are mangrove forests and swamps.
Recent Cyclone Mocha affecting the Sundarbans
Bangladesh
What Coastal processes occur in the Sundarbans ?
The silt and clay deposits are quite resistant to erosion, with small interconnecting river channels flowing. The larger channels are generally 2km wide flowing north to south due to strong tidal currents.
Sediments like sand are washed out and deposited on banks, leading to dunes when southwesterly monsoon winds blow.
What is the importance of Mangroves in the Sundarbans ?
Mangroves are extremely important to the ecosystem providing timber, and protecting the shoreline from floods and shoreline erosion.
What is the importance of Mangroves in the Sundarbans ?
Mangroves are extremely important to the ecosystem providing timber, and protecting the shoreline from floods and shoreline erosion.
What are the Natural Challenges for the people of the Sundarbans ?
- Coastal Flooding
- Cyclones
- High Levels of Salinity in the Soil
- Instability of the islands
- Accessibility
- Human eating tigers (Bengal Tiger)
What are the Human Challenges for the people of the Sundarbans ?
- Over-exploitation of coastal resources from vulnerable habitats.
- Conversion of wetlands to intensive agriculture and settlements
- Destructive fishing techniques
- Lack of awareness of the environmental and economic importance of the region
- Resource conflicts
What are the Mitigation processes undertaken the Sundarbans ?
- Good level of social capital
- Threat of natural disasters means there has been a significant investment in infrastructure.
- Recent human pressures like deforestation
could utilize a number of open access natural resources. - Density of 30 trees per 0.01
hectares can reduce the force of tsunami by 90%
What are the different options of coastal management ?
- Do nothing
- Hold the line
- Advance the Line
- Managed retreat / realignment
What are the Shoreline Management Plans (SMPs)
Introduced in 1995. DEFRA overseas the UK coastal management, each cell has its own management plan. The management objectives of SMPs are continually reviewed;
* provide an assessment of the risks associated with the evolution of the coast
* provide a framework to address the risks to people and to the developed, historic and natural environment
* address risks in a sustainable way
* provide the policy agenda for coastal defence management planning
* promote long-term management policies for the twenty-second century
* aim to be technically sustainable, environmentally acceptable and economically viable
* ensure management plans comply with international and national nature conservation and biodiversity legislation
What is the ICZM ?
The integrated coastal zone management, recognises coastal shorelands, lowlands, intertidal areas, lagoons, and open waters as a single interacting and indivisible resource unit that lies between the upland and the open sea and whose future must be planned and managed in combination.
What is the difference between SMP and ICZM ?
The shoreline management plans are the actual PLANS invovling defences and holding the line etc.
ICZM - integrating would be for example beach stabilisation, as it INTEGRATES - fits in- with the environment and wildlife. Creates, not destroys.
