Coastal Systems & Landscapes Quiz

Coastal Systems and Landscapes

• Constructive Waves:

  • Long wavelength, low height
  • Strong swash, weak backwash
  • Sediment deposited on the beach
  • 6-10 waves per minute

• Destructive Waves:

  • Short wavelength, high height
  • Strong backwash, weak swash
  • Sediment removed from the beach
  • 11-15 waves per minute

• Wave Refraction:

  • Waves bend as they approach an uneven coastline.
  • Energy concentrated at headlands, reduced in bays.

• Tides:

  • Changes in sea level due to the gravitational pull of the Moon and Sun.
  • The UK typically experiences 2 high and 2 low tides daily.

• Tidal Range:

  • The difference between high and low tide levels.

• Spring Tides:

  • Occur during new and full moons.
  • Sun, Moon, and Earth aligned, combining gravitational forces.
  • Result in higher high tides and lower low tides.

• Neap Tides:

  • Occur during first and last quarter moons.
  • Sun and Moon at right angles to Earth.
  • Result in lower high tides and higher low tides.

• Tidal Ranges (types):

  • Micro-tidal: less than 2 meters
  • Meso-tidal: 2-4 meters
  • Macro-tidal: over 4 meters

• Storm Surge:

  • Sea level rise caused by strong winds pushing water towards the coast, and by lower air pressure associated with storms
  • Can cause widespread flooding.

• Storm Surge Factors:

  • Storm strength and size
  • Approach direction
  • Seabed shape

• Currents:

  • General water movement in a specific direction.

• Rip Currents:

  • Strong underwater currents near the shoreline.
  • Created by wave action.

• High-Energy Coastlines:

  • Dominated by strong, destructive waves.
  • Often rocky, with headlands, cliffs, & wave-cut platforms
  • High erosion rates relative to deposition rates.

• Low-Energy Coastlines:

  • Dominated by weak. constructive waves.
  • Often sandy, with beaches.
  • High deposition rates relative to erosion rates.

• Sediment Cells:

  • Coastline sections with contained sediment movement.
  • 11 sediment cells in the UK.

• Factors Affecting Coastal Erosion:

  • Waves
  • Rock type (lithology)
  • Coastline shape
  • Presence/absence of beaches
  • Sub-aerial processes
  • Human interventions

• Accretion:

  • Deposition of sediment, increasing beach width.

• Cusps:

  • Semi-circular depressions on beaches that channel swash and backwash, leading to erosion.

• Storm Beaches:

  • Ridges of large boulders deposited by high-energy waves.

• Berms:

  • Ridges of deposited material on beaches, formed by constructive waves.

• Ridges and Runnels:

  • Wave energy spreading across beaches, creating ridges and intervening hollows (runnels).

• Swash-Aligned Beaches:

  • Waves parallel to shoreline
  • Develop wider beach profiles
  • Often influenced by constructive waves
  • Berms, dunes common.

• Drift-Aligned Beaches:

  • Waves approach at an angle to shoreline
  • Longshore drift transports sediment
  • Beaches tend to be narrower.
  • Spits, bars, tombolos common

• Spit:

  • Long, narrow accumulation of sediment (sand, shingle) extending from the coast.
  • Spurn Point, Yorkshire, is an example.

• Spit Formation:

  • LSD deposits sediment across river mouths.
  • Straight spits or compound spits with recurved ends.
  • Sheltered areas behind spits often develop mudflats and salt marshes.

• Flocculation:

  • Freshwater mixing with saltwater (brackish water).

• Bars:

  • Spits that extend across bays, connecting headlands.
  • Slapton Sands is an example.

• Sand Dunes:

  • Hills of sand deposited by onshore winds.

• Sand Dune Formation Factors:

  • Abundant sand
  • Strong onshore winds
  • Adequate tidal range

• Dune Types (Order):

  • Embryo
  • Foredunes
  • Yellow dunes
  • Grey dunes
  • Dune slack
  • Mature dunes

• Salt Marshes:

  • Coastal ecosystems regularly flooded by tides.

• Salt Marsh Formation:

  • Deposition of sediment in sheltered areas.
  • Gradual transition from mudflats to saltmarsh as sediment builds up.

• Eustatic Change:

  • Global sea level change due to the volume of water in the oceans.

• Causes of Eustatic Change:

  • Melting glaciers (warmer temperatures)
  • Thermal expansion of water (warmer temperatures)
  • Formation of ice sheets (cooler temperatures)

• Isostatic Change:

  • Local sea level changes due to land rising or sinking.

• Compression (Isostatic):

  • Land sinks slightly due to the weight of stored water in glaciers.

• Decompression/Isostatic Rebound:

  • Land rises after ice melts, causing sea level drop

• Emergent Coastline:

  • Coastline exposed as sea level falls.

• Submergent Coastline:

  • Coastline flooded as sea level rises.

• Raised Beaches:

  • Wave-cut platforms & beaches elevated above current sea level
  • Formed by isostatic rebound.
  • Example: Prawle Point.

• Ria:

  • Submerged river valley.
  • Wide & deep at the mouth, narrowing & shallowing inland.
  • Example: Kingsbridge Estuary.

• Fjords:

  • Submerged glacial valleys.
  • Steep, deep valleys.
  • Example: Loch Fyne.

• Dalmatian Coastline:

  • Parallel valleys flooded, creating a chain of islands parallel to the coast
  • Example: Croatia.

• Mangroves:

  • Coastal shrubs & small trees in saline or brackish water.

• Coastal Protection Goals:

  • Prevent/reduce flooding, erosion
  • Stabilise beaches, dunes, and estuaries.

• Coastal Management Options:

  • Hold the line
  • Do nothing & monitor
  • Retreat the line
  • Advance the line

• Shoreline Management Plan (SMP):

  • UK government plan for managing sediment cells along the coastline.

• Integrated Coastal Zone Management (ICZM):

  • Comprehensive coastal management approach considering all stakeholders. (International, not used in the UK)

• Coastal Management Aims:

  • Sustainable economic and social activity.

• Hard Engineering:

  • Physical barriers against natural processes.
  • Expensive.

• Soft Engineering:

  • Works with natural processes.
  • Less expensive.

• Hard Engineering Examples:

  • Sea walls, breakwaters, revetments, rock armour, cliff fixing, gabions, groynes

• Sea Walls:

  • Recurved structures deflecting wave energy.
  • Effective, but expensive.

• Breakwaters/Offshore Reefs:

  • Reduce wave energy before reaching the shore
  • Effective but can be damaged.

• Revetments:

  • Structures to absorb wave energy and reduce LSD. (30-50 year life expectancy)

• Rock Armour:

  • Large rocks placed in front of cliffs to absorb wave energy.
  • Cheaper than seawalls.
  • Often unattractive.

• Cliff Fixing:

  • Stabilizing cliffs to reduce erosion.
  • Often more environmentally friendly than hard engineering

• Gabions:

  • Wire cages filled with rocks to absorb wave energy.
  • Relatively cheap.

• Groynes:

  • Barriers to trap sediment and slow LSD.
  • Cost-effective.

• Soft Engineering Examples:

  • Marsh creation, beach nourishment, do nothing, managed retreat, dune stabilisation

• Marsh Creation:

  • Allow low-lying areas to flood to reduce wave energy
  • Creates important wildlife habitats.

• Beach Nourishment:

  • Relocating lost beach sediments.

• Do Nothing:

  • No action to prevent flooding or erosion.
  • No cost.

• Managed Retreat:

  • Abandoning sea defenses.
  • Allows erosion to continue.

• Dune Stabilisation/Regeneration:

  • Planting vegetation to stabilise dunes.

Test your knowledge on coastal systems and landscapes, focusing on the characteristics of constructive and destructive waves, wave refraction, tides, and their effects on shorelines. This quiz covers essential concepts like tidal ranges, spring and neap tides, and more.