coasts

• closed system


  A system in which no matter is allowed to enter or leave
• open system


  matter can enter from or escape to the surroundings
• dynamic equilibrium


  When the inputs and outputs are balanced. For example, the beach
• feeback


  If the equilibrium of the system is upset by a change in one of the elements
• negative feedback


  The effect of an action are nulified by its subsequent Knicks on effects
• Cryosphere


  All the frozen parts of the earth. The ice found in water near the artic including lakes which have been frozen. Also including ice and snow on land eg. greenland. The snow and ice helps keep the earths climate constant & reflects the suns rays. When the ice breaks of it becomes part of the hydrosphere
• Biosphere


  The worldwide ecosystem eg.plants and animals (living things). A closed system. It is too sustain life.
• Hydrosphere


  The total amount of water on the planet. Can be a liquid, vapour or ice. The saturation in clouds, precipitation in rain or snow inputs into oceans, rivers & lakes.
• Lithosphere


  The solid outer layer of the earth including the upper mantle and the crust. Bounded by the atmosphere above and asthenosphere below. Rain goes into the ground, plants absorb the water and sunlight, carbon is stored in the soil and then leaves the soil through soil respiration
• Atmosphere


  The layer of gas surrounding the planet. Protects the earth from incoming solar rays. It circulates the gases for animals/plants to survive. Also responsible for our weather.
• Positive feedback


  The effects of an action are amplified or multiplied by subsequent knock on effects
• Swash-aligned beaches


  Forms in bays affected by waves arriving parallel to the shore. High energy waves transport sand leaving shingle. Low energy waves deposit sand/mud
• Drift aligned beaches


  When waves approach the coast from an angle. Longshore drift moves sediment from the spit.
• High energy waves/coasts


  Occur at stretches of a coastline with a large fetch and the waves are more powerful. EG. the Atlantic ocean. The rate of erosion exceeds the rate of deposition
• Low energy waves/coasts


  Stretches of the coast where waves are less powerful or where the coast is sheltered. Landforms like beaches, spits and coastal plains
• Wave refraction


  When the waves approach and hit the headland (parallel). It erodes and takes the energy. The waves refract and form the shape of the bay. Deposition occurs. Negative feedback occurs when the land returns back to the original shape.
• Depositional landforms; Spit


  Forms due to LSD when the sand/shingle moves along the beach. The spit eventually forms a tombolo. A saltmarsh can form.
• Depositional landforms; Tombolo


  Forms between a small island and mainland. Deposition occurs where waves loose energy and a tombolo begins to build up. It is covered by high tide
• Depositional landform; Offshore Bar

  Submerged ridges of sand are created by waves offshore. Destructive waves erode sand from the beach with backwash and deposit it offshore
• Depositional landform; Barrier beach/island


  Long/narrow islands of sands which run parallel to the shore and are detatched. They form in areas where there is a good supply of sediment, a small tidal range and fairly powerful waves.
• Mudflat


  Forms in a sheltered, low energy environment such as rivers. They develop when mud and silt are deposited. Colonised by vegetation that can survive in high salt levels
• Salt Marsh


  When there is a mudflat and the plants trap more mud and silt which forms a saltmarsh which builds up. They occur when fresh water meets salt water.

  - Purifies water

  - Acts as a natural defence to storms

  - Stores carbon

  - Natural habitat for wildlife
• Factors affecting saltmarsh development

  - Weather; storms erode

  - Tidal changes; changes in currents alter species & increase erosion

  - Wave type; change in type, size and nature can affect stability

  - Climate; Affects the species type, growth rates & sea levels

  - Sea levels; rise can upset equilibrium & destroy the marsh

  - Human action; commercial, recreational & industrial activity damages the marsh

  - Sediment supply; Supply can change (increase/reduce) the availible silt

  - River regime; Changes in currents and volume affects erosion
• Sand dune succesion


  1. Embryo dune- sand is collected in the rocks

  2. Fore dune- Sand is blown onshore and builds up against plants. There is waxy leaves to retain moisture

  3. Yellow dune- Wind speed reduced & Marram grass thrives in being buried by sand

  4. Grey dune- A closed vegetation communtiy, marram grass cant compete. Shrubs start to form

  5. Dune stack- Aquatic plants which occur in low hollows between dune ranges. The water table is high in winter

  6. Woodland/mature dune- Oak and pine trees which are nutrient rich. Potential for human intervention.
• Summary of sand dune (formation)

  -Forms when snd is deposited by LSD moving up the beach by wind.

  - Sand trapped by driftwood is colonised by plants/grass. Vegetation stabalises the sand and encourages more sand to accumilate forming embryo dunes

  -Overtime the oldest dunes migrate inland as newer embryo dunes are formed. These mature dunes can reach heights up to 10m
• Aim of coastal management

  To provide defence against and mitigate impacts of flooding. Protection against and mitigate the impacts of coastal erosion
• Soft Engineering


  Using natural processes to protect the coastline but doesnt prevent/control the natural erosion
• Beach nourishment


  Adds sand/pebbles to a beach. It is cheap and easy to maintain but needs constant maintenence
• Cliff drainage


  Removes water from cliffs to prevent landslides and slumping. It is effective for soft rock but the cliff can still retreat and collapse when its dried out
• Dune stabilisation


  Marram grass planted to stabilise dunes. It provides wildlife and is cheap/easy but is time consuming
• Marsh creation


  Managed retreat allows low lying coastal areas to be flooded ; salt marsh. It is cheap and acts as a natural buffer but agricultural land is lost
• Hard engineering


  Attempts to stop coastal erosion by controlling/resisting environmental processes using man-made structures
• Revetments


  Sloped wood/concrete structure and the bottom of a cliff which breaks up the waters energy. It is inexpensive to build but looks unnatural.
• Offshore breakwater


  A partly submerged barrier to break up water before the beach. It is effective permeable barrier but is a navigation hazard
• Sea wall


  Concrete wall at the top of the beach/foot of cliff. It provides a promenade and effective prevention but is unnatural and expensive
• Rock armour


  Large rock at the bottom of a cliff and breaks the waters energy. It is cheap and easy and can be used for recreation but looks out of place and dangerous
• Groynes


  Wood/rock structures at a right angle to the coast and traps sediment. It works with natural processes and isn't expensive but starves the beach along the coast and is unnatural
• SMP


  Each sediment cell has its own smp. Intervention at one cell doesnt affect another
• Hold the line


  Prevents any further erosion
• Advance the line


  Extends to coast into the current sea