Sediment Cells Flashcards
Transportation - Traction
Sediment rolls along floor
Transportation - saltation
Bounces along - 2-10cm above beach
Transportation - suspension
Carried along in column of water (makes water muddy)
Transportation - solution
Dissolved in water
Deposition - gravity settling
Heavier particles lose energy so can’t transport anymore - fall
Deposition - flocculation
Clay particles attract and clump together
Increased mass means lose energy - falls
LSD
Most efficient at 30°swash
Backwash at 90° because of gravity
Drift aligned beach
Aligned to diagonal swash (LSD)
Swash aligned beach
Aligned to parallel swash and backwash (90°)
Sediment cell (11 in UK)
Closed system or sources, transfer and sinks of sediment
Sediment cell - sources
Cliff erosion Onshore currents River transport Wind sediment (land) Subaerial processes Marine organisms
Sediment cell - transfers
Littoral drift LSD Swash and backwash Tidal and ocean currents Wind
Sediment cell - sinks
Back shore (sand dunes)
Foreshore (spits and beaches)
Nearshore (bars)
Offshore (barrier islands)
Coastline topography
Shapes and divides the land (headlands)
Creates the sub cells of the sediment cell
Dynamic equilibrium
Inputs from sources balances deposits in sink
Constant sediment movement
Changes to dynamic equilibrium
Climate change
More erosion
Storm even can disrupt
Seasonal change
Negative feedback
Change has effects that work against original change
Erosion leads to rockfall - collapsed debris acts as barrier against waves - less erosion
Positive feedback
Change has effects that increase original change
More wind erosion during storm removed vegetation - leads to more wind since less blocking
