coasts L7? Sediment Cells and Feedback Flashcards
(8 cards)
What is a LITTORAL/SEDIMENT CELL
A closed physical system with INPUTS, OUTPUTS, STORES & TRANSFERS
Sediment movement occurs where inputs and outputs are balanced
11 of them in England & Wales
What are SOURCES?
+examples
WHERE SEDIMENT COMES FROM
- eroded parts of cliffs
- inland - brought to coast by rivers
- blown from inland
- constructive waves
what are TRANSFERS?
+examples
HOW THE SEDIMENT IS TRANSFERRED
- longshore drift
- tides, constructive and destructive waves
- human activity (beach nourishment)
what are SINKS?
+examples
WHERE SEDIMENT ENDS ITS JOURNEY BEFORE BEING REDISTRIBUTED AROUND THE CELL
- Deposition
- spits
- bars
- tombolos
- cuspate forelands
- salt marshes
- sand dune succession
- foreshore berms
- nearshore bars
- offshore bars
what is a SEDIMENT BUDGET
relationship between erosion and deposition
it allows us to be able to calculate how fast a coast is eroding
what is NEGATIVE FEEDBACK
the good one
- returns balance by removing something
- erosion -> creates rock armour
- sand dunes destroyed -> offshore bar that reduces wave energy
- nature. bad thing -> good conditions -> slow erosion
what is POSITIVE FEEDBACK
the bad one x
- leads to disequilibrium by pushing it to the point of no return
- increased storms - long term erosion of sand dunes - can’t recover
- rising sea levels; increase amount of erosion of spits & estuaries - removing sediment faster than replaces
- humans and climate change
bad thing -> more bad thing -> increase erosion
The Holderness Coast Sediment Cell
source:
- river sediment from Humber Estuary
- chalk headland
- boulder clay cliffs
transfer:
- some sediment offshore
- longshore drift
sink:
- estuary muds deposited at mouth of river behind spit
- deposition evident at Spurn Head
- off shore bars
- sediment deposition on lincolnshire coast & in the wash
