sediment cells Flashcards
what type of system is a sediment cell
a closed system
effect in sediment cells
any action from one place such as erecting groynes can have impacts elsewhere
what separates each cell
a physical barrier that prevents sediment moving any further along the coast
how many sediment cells are there in the english and welsh coastline
11 sediment cells
what 3 parts are there to a sediment cell
-source
-transfer
-link
what kind of sediment is transferred and why
-finer sediment in suspension out at sea (such as boulder clay from holderness)
-larger sediment isnt transferred
what is the sediment budget
the amount of sediment available within a sediment cell
what is in equillibrium with the amount of sediment avaikable
-depositional features
what do sediment cells do under natural conditions
operate under a state of dynamic equillibrium
what is dynamic equillibrium
when sediment inputs balance outputs to sinks
what is a source
where sediment is eroded from cliffs or sand dunes, or can be offshore like offshore bars
-river systems are also important source
source examples at holderness coast
-hornsea’s boulder clay
-river humber
what s a transfer zone
-where sediment is moving along coast by longshore drift and offshore currents
what is a sink
locations where dominant process is deposition at a certain time
can coastal features be both a sink and source?
Yes
-depends on if the dominant process is erosion or deposition at the time
what is positive feedback
-if the sediment budget falls
-waves continue to transport sendiment
-erosion may therefore increase in some areas bc sea has surplus energy
-one change leads to another
what is negative feedback
-if sediment budget increases
-more deposition is likely
-sea corrects itself bc it can only carry so much
-surplus is deposited
-returns to situation where it can handle sediment supply
example of negative feedback at holderness (cliff)
-large amount of cliff collapse may occur such as chalk and boulder clay base
-slow down erosion by protecting cliff from wave attack
example of negative feedback at holderness (spit)
-major erosion at spurn head spit
-increased depositon offshore
-offshore bar
-reduces wave energy
-spit has time to recover
examples of sources
-cliffs
-river system
examples of sinks
-offshore bar
-spit
-sand dunes
