Chapter 1 Coastal landscapes Flashcards
he operation of the coast as a system Geographical content: • The coastal system including inputs, outputs, stores and transfers of energy and materials • Terrestrial and offshore supplies of sediment • Coastal sediment cells • Dynamic equilibrium in the coastal system and zone of rapid changes Case studies- budget= barton on sea and bangladesh sediment cells= NE Norfolk sediment cell equilibrium=
the coastal zone is what type of system
dynamic open system
whats a dynamic open system have
inputs and outputs of energy and materials such as sediment
what type of boundarys are on the edge of a costal systems
spatial boundaries
whats the process response method
states that the morphology of any coastline is the product of the processes operating in the system
e.g coastal cliff retreat
whats a sediment budget
balance between sediment added and removed from the coastal system
how does signifigsnce of input snd output vary in a soft rock named example
(they vary)
in Barton on sea cliffs are the major terrestrial supplier of sediment however in Bangladesh Ganges-Brahmaputra Delta fluvial sediment is the main supply
outputs to the coastal system
longshore drift
loss to offshore and transfer to sediment stores down the coast
how in a balanced budget input and output are volumes in equilibrium
Volume of sediment in= volume of sediment stored + volume of sediment out
what upsets sediment balance
human actions such as building dams or hard engineering defences because the inputs decline
How does the coast aim to stay in a state of equilibrium
so its morphology will change rapidly in response to a storm event
3 types of equilibrium
steady state
meta stable
dynamic
whats steady state equilibrium
where variations in energy and the morphological response do not deviate far from the long term average.
e.g where and when sea cliffs recieve more or less equal atmospheric and marine energy, the profile of the cliff tends to stay the same from yr to yr espec for resistant rocks
whats meta stable equilibrium
environment switches between 2 or more states of equilibrium, stimulated by some sort of trigger
e.g actions of high energy events such as storms can remove a whole beach in hours which rapidly changes a coastal system from 1 state to another
whats dynamic equilibrium
involves a change in equilibrium conditions but in a much more gradual manner then for meta stable equilibrium over a longer period of time
e.g response to sea level rise by coasts. wave energy actions occur higher up the shore and cliff and beach profiles adjust as a consequence
where does equilibrium apply
not all coastal areas
energy environments can change wihtin just a few metres, spatially aswell as temporarily further complicating the issue
when do feedbacks occur
occur as the result of change in a system and theyre either pos or neg, switching the system to a new state of equilibirum of attempting to recover the systems og state respectively
whats positive feedback
amplify initial change in the system
normally bad and moves away from equilbirum
whats negative feedback
diminishes or dampens effect of change
good
stabilises system so equilibrium
NE norfolk sediment cell example location
stretches 50km from Flamborough Head in the north to Spurn Head at the Humber Estuary
three principal supplies of sediment
river, cliffs and dunes
of the three principal supplies of sediment which is thought to be the most important
river
whats backshore
area between high water mark and the landward limit of marine activity. changes take place here only during storm activity
whats foreshore
area between the HWM anf the lWM most important zone for marin processes in times not infleunced by storm activity
sediment cell defintiion
a length of coast and its nearshore area within which the movement of sediment is self contained
