Coastal Systems and Landscapes Flashcards
What is a system
Set of interrelated components working together towards a process
What are the main sources of energy in coastal systems
Wind
Waves
Currents
Tides
State the differences between constructive and destructive waves
Constructive:
- higher wavelength
- short height
- low frequency
- powerful swash, weak backwash
- net material gain
Explain wave refraction
- Friction with sea floor when waves at an angle
- curved coastline increases refraction
- increases erosion at headland
- increases wave frequency in bay
Explain longshore drift
Waves approaching beach at 45 degrees, flow of water parralel to shore transporting sediment.
What are rip currents
Strong currents moving away from shore
- Sea waves piled up along coastline
- runs parallel, then flows into breakzone
What are tides
Periodic rise and fall of sea level by gravitational pull of the moon
Tidal range - difference between high and low tide.
What is a spring and neap tide
Spring - greatest difference between high and low tide - moon and sun at 90 degree angle to earth
Neap - lowest difference between high and low tide - moon, sun and earth form a line
Compare high and low energy coastlines.
High energy coastlines:
- high wave energy
- high levels of erosion - higher than rate of deposition
- headlands, cliffs, wave cut platforms
Atlantic coastlines as example
low energy coastlines:
- beaches and spits
- baltic sea as example
What are the 4 main types of marine processes and give examples
- Erosion - hydraulic action, wave quarrying, abrasion (corrasion), attrition, solution (corrosion)
- transportation - Traction, Saltation, Suspension, Solution, Littoral Drift.
- sub-aerial weathering - mechanical, biological, chemical
- mass movement - landslides, rockfall, mudflows, rotational slumping, runoff
Explain the formation of a Saltmarsh
Sheltered shorelines, often at river estuaries. Flocculation of particles. Hallosere - plant succession
Name the types of sea level rise
Eustatic - Global change - volume of water or shape of basin - changing climate (ice melting / thermal expansion)
Isostatic - local change - movement of land relative to the sea - uplift / depression, subsidence of land (drying saltarsh), tectonic plates
What are submergent and emergent coastlines
Submergent (transgressive shorelie) - land becoming inundated due to rise of sea levels.
Emergent (regressive shoreline) - land exposed by falling sea levels
Name some landforms of submergent and emergent cosstlines.
Submergent:
- Rias
- Fjords
- Dalmation coastlines
Emergent:
- Raised Beaches
- Marine Platforms
Explain coastal management
Provide protection against erosion and flooding.
Examples - stabalise beaches against LSD, protect salt marshes, stabilise sand dunes
What are shoreline management plans?
Introduced in UK 1995
Split UK coastline into 22 main sediment cells
3 types of responses:
- short term - last 0 - 20 years
- medium term - 20 - 50 years
- long term - 50 - 100 years
Updated since 2015
What are the actions that can be done through SMP’s?
Hold the line - current defenses maintained
Advance the line - new defenses built seaward of existing.
Managed realignment - foward / backward to control movement - increase to flooding managed
Do nothing - no active intervention
Name some dissadvantages of SMP’s
- time consuming and expensive
- unpopular decisions
- difficult to educate locals - get importance across
- economically unsustainable
Explain Intergrated Coastal Zone Management (ICZM)
UN earth summit - Rio De Janeiro 1992
- links to Agenda 21
Used worldwide
- considers all elements of coastal system.
- protect coastal zone in a relatively natural state
- dynamic strategy - re-evaluated if land use changes.
How are ICZM’s intergrated
Environment viewed as whole - interdependence
Different uses are considered - fishing, farming, locals, tourism etc
Local, regional and national levels of authority have input.
[CS] Background information on the Sundarbans
- Delta of the Ganges, Brahmuputra, Meghna.
- worlds largest mangrove forest
- Majority protected as national park
- Mangroves adapted for salinity and mudflats
- agriculture activities destroyed 17,179 hectares of Mangroves in 3 decades
[CS] what are the risks in the Sundarbans
Natural:
- coastal flooding
- cyclones
- salinity
- island instability
- Accessibility
- human-eating Tigers
Human:
- over-exploitation of resources
- converision of wetlands to agriculture + settlement
- destructive fishing
- lack of environment awareness
- conflicts for resources
- lack of coastal issue awareness
Coping methods
Resiliance - Ability to cope with challenges environment presents.
Mitigation - strategies to reduce severity of hazards.
Adaptations - attempts to live with hazards by adjusting living conditions.
