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Coastal Systems - Coggle Diagram

- - - - Balance between sediment being added to and removed from the coastal system
- - - - More prominent in the UK where there are few coastal settlements.
  - - - Focus on sustainability of of management programmes.
      - 22 SMPs across the coast of England and Wales, planning across different time terms.
        
        These include SMP 2 The Tyne to Flamborough Head and SMP 14Isle of Wight.
      - Key Features
        
        Provide an assessment of the risks associated with the evolution of the coast.
        
        Provide framework to address the risks to people and to the developed, historic and natural environment.
    - - Aims for coordinated application of the different policies affecting the coastal zone and related to activities.
      - 'Ecosystem based approach'
        
        Operates within the limits of natural resources and ecosystems.
      - Background of initiative
        
        Coastal zones are some of the most ecologically productive areas in the world.
        
        Natural assets of coasts have for millennia made them popular for settlements, tourists, businesses and ports.
        
        Concentration of people puts great pressure on coastal environments
        
        This leads to biodiversity loss, habitat destruction, pollution, conflicts between stakeholders, overcrowding.
        
        Areas that are most vulnerable to impacts of climate change and natural hazards.
        
        Coastal management previously had been to sectoral, decisions undermine each other.
      - The cycle of integrated coastal zone management:
        
        Planning
        
        Decision making
        
        Managing and monitoring of implementation
        
        Information collection.
      - Maritime Spatial Planning works alongside ICZM, involves mapping the activities of all stakeholders in a particular coastal zone
        
        These mean all involved can visually assess the cumulative impacts, which then inform future plans.
        
        Connecting offshore wind turbines to the electricity distribution network on land.
        
        Addressing the impacts of strategies to protect coastlines against erosion and flooding on activities like aquaculture and fisheries.
        
        Utilising powerful GIS and geospatial mapping techniques
- - - - Emergent
        
        Raised beaches remains of eroded cliff lines can often be found behind the beach with wave cut notches as the land rose from isostatic recovery above current sea level.
        
        Sea caves and arches are features of past coastal erosion now well above the active coastal zone where the ocean interacts with the land.
      - Submergent
        
        Rias form when valleys in a dissected upland area are flooded
        
        The Kingsbridge Estuary in Devon, provides a natural harbour with the deepest water at its mouth.
        
        Fjords formed when deep glacial troughs are flooded by a rise in sea level.
        
        They are long, steep-sided, U-shaped cross-section and hanging valleys valleys
        
        They are much deeper than rias inland
        
        The shallower entrance marks where the glacier left the valley.
        
        Dalmation Coasts form in a landscape of ridges and valleys parallel to the coast
        
        When sea levels rise, valleys flood, but the tops of ridges remain exposed, forming a series of offshore islands such as Croatia
    - - Contemporary sea level change from climate change and tectonic activity.
      - Tectonic Activity can lower and raise sea levels.
        
        They rise when non-sub ducted material rebounds
        
        However the folding of plates may also cause an increase int he volume of the ocean basin.
- - - - Factors affecting coastal erosion
        
        Waves
        
        Rock type (lithology)
        
        Geological structure (faults)
        
        Presence of a beach (absorb wave energy)
        
        Subaerial processes
        
        Coastal management.
      - Landforms of Coastal Erosion
        Landforms are individual components in the coastal landscape.
        
        Cliffs and Wave Cut Platforms
        
        Cliffs form as the sea erodes the land , and retreat overtime from waves and weathering.
        
        Cause a notch to form at the high water mark, eventually develops a cave.
        
        Rock becomes unstable above with nothing to support it, and collapses.
        
        Caves, Arches and Stacks
        All connected as part of a sequence of coastal erosion landform developments.
        
        They are cliff profile features
        
        Weak areas in rocks are eroded to form faults and then caves.
        
        Caves on the opposite side of a narrow headland may eventually join up to form an arch.
        
        When an arch collapses as the pressure becomes too much a stack is formed.
        
        Old Harry Rocks, Dorset
        
        Headlands and Bays
        Form on bands of alternating hard and soft rock
        
        Discordant coastlines
        
        Soft rock is eroded more quickly, forming a bay, the harder rock erodes more slowly so sticks out to the coast as a headland.
  - - - Traction
      - Solution
      - Saltation
      - Suspension
  - - - Marine Deposition
        
        Sediment carried by water is deposited.
      - Aeolian Deposition
        
        Sediment carried by wind is deposited.
      - This happens either by the increase in sediment load or the decrease of wind or water energy.
        
        Wind and water slow down because:
        
        Friction increases if water enters shallow areas, or wind reaches land which slows it down.
        
        Turbulent flow Wind or water becomes an obstacle, flow becomes rougher and overall speed decreases
    - - Beaches
        Extends from the high tide to low tide.
        A period of constructive waves leads to beach accretion.
        
        Sand becomes compact when wet due to its particle size. So most swash returns as backwash material carried back down the beach which forms runnels and ridges which run parallel to the shoreline and broken by channels that drain the water off the beach.
        
        Shingle beaches are steep and narrow, whereas sand beaches are formed from smaller particles, wide and flat.
        
        Swash aligned beaches form in low energy environments, waves arrive parallel, sediment moves up and down but not a lot of littoral movement.
        
        Drift aligned beaches where waves approach the beach at an angle, moves sediment along through longshore drift, culminating in the formation of a spit.
        
        Storm beach forms at the back of the beach with strong swash at spring high tide creating a ridge composed of the biggest boulders, below this forms berms which are ridges built by constructive waves.
      - Spits
        Long narrow feature made of sand or shingle that extends from the land into the sea or across an estuary.
        
        They form on drift aligned beaches or across river mouths.
        
        Sediment is moved along the coast by longshore drift, but if the shoreline suddenly changes direction sediment builds up, carrying on moving laterally.
        
        The end of the spit will begin to curve round as wave refraction carries material round into the more sheltered water behind the spit. (Recurved tip)
        
        Over time, several recurved ends may be abandoned as waves return to original direction
        
        Multiple recurved ends are called compound spits.
        
        Area behind recurved spit develops into mudflats or saltmarshes.
        
        Silt and mud are deposited by the river or tide, colonised by vegetation.
        
        These trap more silt and mud building up to an area of saltmarsh whcih remains exposed for longer and longer between tides.
        
        Erosion by tidal currents or streams form channels in the surface, which may be permanently flooded or dry.
      - Tombolo
        A beach, or ridge of shingle that has formed between a small island and the mainland.
        Waves lose their energy.
        They may be covered at high tide.
      - Offshore bars
        Submerged ridges of sand created by waves offshore from the coast.
        destructive waves erode sand from the beach with their strong backwash and deposit it offshore.
        They can absorb wave energy thereby reduce effects of eaves on the coastline.
      - Bars
        A beach or spit extends across two headlands.
      - Sand dunes
        Prerequisites of formation include:
        
        large quantities of available sand washed onshore by constructive waves
        
        large tidal range creating a large exposure of sand that can dry at low tide.
        
        dominant onshore winds blowing sand to the back of the beach
        
        obstacle to trap the sand (Marram grass a pioneer species) helps stabilise the sand, and cause vegetation succession.