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What is a system?-A process that transforms inputs to outputs What is an input?-Matter or energy that is consumed by a system -Coastal inputs – energy is wind, waves, tides -Material input – products of cliff erosion, subaerial erosion, glacial processes What is an output?-Matter or energy produced by a system What is a boundary?-What entities lie inside and outside a system What are the components of a boundary?-Elements – make up of a system e.g. rain, sand, plants, animals -Attributes – characteristics of elements that can be seen and measured e.g. size, volume, temperature, mass -Relationships – associations between attributes and elements based on cause and effects What are the coastal processes?-Erosion, transportation, deposition What are the coastal stores?-Beaches, dunes, salt marsh, cliffs, wave cut platforms What are the 3 types of systems?-Open – mass and energy transfer across boundary. Flow of matter and energy -Closed – constant mass where there is no matter flow. Only energy flow -Isolated system – theoretical system, no interaction between system and surroundings. No energy or mass flow What are the 4 key subsystems?-Hydrosphere, geosphere, biosphere, atmosphere What is the carbon and water cycle?-Links the 4 sub-systems -Systems that form relationships which allow energy and mass transfers between spheres What is positive feedback?-Where a flow or transfer amplifies an initial change What is negative feedback?-Where a flow or transfer leads to the reversal of an initial change What is dynamic equilibrium?-Represents a state of balance within a constantly changing system What factors effect the dynamic equilibrium of a coast?-Sand supply – sand gives shorelines protection from the waves. Less sand means more erosion -Change in sea levels – e.g. New Zealand sea level rise is 15cm per 100 years and will rise further due to climate change -Wave energy – erosive activity is affected by the wave height, the angle, and the amount of sand -Location of shore What does coastline mean?-When the land meets the sea -The boundary between the terrestrial and marine boundaries Coastlines are constantly changing
due to:
-Interaction of land forms -Rock type -Human impacts -Atmospheric changes -Marine processes What factors affect the coastline?-Marine – waves and tides -Sedimentation – rivers transport sediment, glaciers release sediment, cliff collapse deposits sediment into water -Atmospheric – rain, temp, wind -Human – pollution, defences, recreation -Geological factors – rock type and structure determine erosional or depositional landforms -Biotic factors e.g. vegetation -Climate – weather effects winds which generate waves and glaciation change sea levels What does fetch mean?-The distance the wind travels How do waves form? 1 / 2
-Wind blows over the sea -Friction with water surfaces cause ripples that develop into waves -The longer the fetch – more powerful wave What is the crest and the trough?-The top and bottom of a wave What is the wavelength?-The distance between two similar points What is the swash?-Forward movement of a wave up to a beach and at a 45 degree angle -Controlled by prevailing wind What is the backwash?-The backward movement of water down a beach when a wave has broken at a 90 degree angle to the beach -Controlled by gravity What is longshore drift?-The transportation of sediment along a stretch of coastline caused by waves approaching the beach -The movement of sediment across the beach caused by the movement of swash and backwash What are destructive waves?-Waves where the backwash is greater than the swash -High wave height, short wave length -Weak swash, strong backwash -Steep beach gradient -High erosion, low deposition What are constructive waves?-Constructive waves are when the swash is greater than the backwash -Short wave height, high wave length -Strong swash, weak backwash -Shallow beach gradient -High deposition and low erosion What are high and low energy coasts?-High energy – strong, steady prevailing winds create high energy waves and rate of erosion is greater than deposition -Low energy – rate of deposition exceeds the rate of sediment erosion What is a swash aligned beach?-Forms in low energy environment e.g. bays -Affected by waves arriving parallel to shore What is a drift aligned beach?-Forms when waves approach at an angle -Sediment moved along beach by LSD Where is the backshore?-Area between high water mark and the landward limit of marine activity What is the foreshore?-The area between high water mark and low water mark -The most important zone for marine processes in times that aren’t influenced by storm activity What is the inshore?-The area between the low water mark and the point where waves stop having any influence on the land beneath them What is the offshore?-The area beyond the point where waves stop impacting the seabed and activity is limited to deposition of sediment What is the swash zone?-The area where a turbulent layer of water washes up the beach following the breaking of a wave What is the surf zone?-The area between the point where waves break forming a foamy/bubbly surface and where the waves then move up the beach as swash in the swash zone Where is the breaker zone?-Area where waves approaching the coastline begin, usually where the water depth is 5,10m What is spring tide?-When the tidal range is greatest -Full moon and new moon -Higher than average What are neap tides?
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