STOCKTON

• Contemporary Strategy - Fencing

  • Response: trampling bach uses 
  • restoration and stabilisation of dunes. 
  • The  Newcastle City Council has implemented a $31.5 million Beach Renourishment program including fences, access ways and signage
  • Made from wire & timber poles 
  • Allows wind/sand pass through undisturbed 
  • Alternate Paths: Beach Renourishment program
• Contemporary Management Strat x2

  Enforces fencing

  Raising awareness & understanding of the stress of trampling over vegetation. 

  Dune reconstruction to occur undisturbed = stabilise dune
• Contemporary Strat- Earthmoving Equipment

  Form an aerodynamic shape manipulating dunes to the ideal slope for ideal vegetation growth. 

  Vegetation can flourish

  Stabilise dunes = trapping and stabilising sand particles, 

  Habitats for species.
• Human-induced changes to coastal dunes

  • Clearing
  • Grazing
  • Vehicles
  • Excessive trampling
• Foredunes


  Densely vegetated = more complex plant communities
• Dunes are mostly found in arid tropical climate zones as they frequently experience strong onshore winds
• Relative location of Stockton Bight


  Between Newcastle in the south & Port Stephens in the north
• Absolute location of Stockton Bight

  Latitude of 32°50'S

  Longitude of 151°53'E
• Accretion Cycle (4 spheres functioning together) forms Coastal Dune Systems

  1. Eroded & transported sand by rivers are deposited onto the shore by waves

  2. Sand dries out

  3. Blown to the back of the beach → vegetation stores it

  4. Destructive waves & currents takes sand back to sea

  5. Sand stored offshore

  6. Slowly deposited back with constructive waves
• Components of the lithosphere on coastal dunes

  • Sand
  • Calcium carbonate → shells of dead sea animals & weathered + eroded rock
• Weathering & erosive processes that occur in lithosphere are important functions for the development of sand dunes

  1. Weathering

  2. Erosion

  3. Breaking down of the lithosphere

  4. Movement & depositing of the weathered material
• Mechanical weathering


  Main processes: hydraulic action & abrasion
• Hydraulic action


  Strong waves are powerful forces & bombard cliff faces with water → loosen the sand particles
• Abrasion


  Loosed particles act as sand paper & loosen other particles
• Fluvial (water) erosion moves weathered material from its original area


  1. River discharge

  2. Longshore drift

  3. Wave action
• Accretion Cycle


  1. Powerful storm waves erode dunes by moving large volumes of sand away from beach & dunes

  2. Aeolian (wind) Erosion moves particles of fine dry sand AWAY from shoreline, moving whole dune systems inland
• Hydrological Processes


  Flows & storage of water<|>Pivotal role in accretion cycle<|>Through the flow of water: rivers, currents, waves & rain<|>Help deposit & removal of sediment<|>Key mechanism in erosive processes
• River Discharge

  Hunter River is the main source of sediment = sand
• Longshore Drift


  Type of current

  Role: Assists transporting sediment in the accretion cycle

  in Sediment that is produced/deposited is transported by the ebb (flow back) & swash (flow on) of waves
• Wave Action

  Crucial role in accretion cycle

  Constructive: Reconstruct eroded foredune areas by depositing sand particles

  Destructive: strong winds, storms and power remove sand off & away
• Rainfall


  Hydrological flow → dev sand dunes<|>Infiltrates sand dunes with ease<|>Heavy downpours can produce runoff → erodes the sandy surface exposing it to wind
• Dynamics of weather and climate

  • Key weather factors: Wind, temp & precipitation
  • Move sand particles in the accretion cycle & provide conditions for vegetation to grow
• Wind


  Onshore prevailing winds Determines SHAPE & EXTENT

  Helps shape, dry, move & weather sand
• Aeolian (wind) transport


  Major contributor to erosion of sand particles AND mover of sand dunes in accretion cycle<|>Sand 1cm in diameter is too big to be transported by aeolian processes
• Temperature


  Arid tropical climate zones = exp strong onshore winds

  Affects ability + time sand dries & for vegetation to be present

  Avg daily maximum in summer 21-2°C & winter 10-15°C

  Assists in the accretion cycle: providing enough heat to dry sand
• Precipitation


  Determines how wet sand gets & assists vegetation growth<|>Influences vegetation cover → help stabilise sand on dunes<|>Role: storage of sand in accretion cycle<|>Heavy rainfall: erode steep dune faces, role: removal of sand in accretion cycle<|>Wet sand is less prone to erosion by WIND
• Amount of Precipitation at Stockton Bight

  Wettest Months: Jan-June

  Assists with the formation of vegetation
• Coastal vegetation


  • Evolved adaptations for poor soils, phosphate accumulation
  • Resilience against salt, wind & dehydration
• Primary dune


  • Supported by resilient vegetation, forms a green ridge with Spinifex, acting as a natural defence against sea invasion
• Formation of secondary dunes


  New mini dunes continue forming while dropping sea levels transform old foredunes into highly vegetated secondary dunes
• Formation of tertiary dunes


  With further sea level drops, tertiary dunes emerge, turning the original dune into a biodiverse coastal forest
• Natural stress

  1. Storm damage: heavy rain, strong winds & power waves

  2. Blowouts: breaches in dunes caused by strong winds

  3. Washover: big storms bring heavy destructive waves that breach foredune area

  4. Bushfires: catastrophic

  5. Introduced species- rabbits & weeds (Bitou Bush)
• Vegetation adaptation to natural stress

  • Propagation
  • New Growth
  • Inputs in Nutrient Cycling
  • Some species need bush fires for their seeds to open
• Vegetation succession helps stabilise dunes again after washover events
• Long term gradual change


  Rise and fall of sea levels<|>Variation in temperature: change type of vegetation that covers the veg zones
• Human impacts (positive and negative)


  • Negative: Reduction in biodiversity, disruption of sediment flow, coastal development, recreation use, cattle grazing, introduction of weeds and pests, sand mining
  • Positive: Fire encourages biodiversity, vegetation stabilises dunes, recent management efforts to eradicate weeds and reduce access
• Sea walls disrupt the accretion cycle by reducing the flow of sediment along the coast, leading to erosion of the foredune area
• Coastal development on the hind dune area transforms it into an urban area, impacting the natural dune system
• Recreational use, such as 4wd driving and trampling by people, causes damage to the dune vegetation
• Sand mining is the most disruptive and controversial human impact, involving the total removal of dune vegetation and taking decades to rehabilitate