C1 coats and rivers Flashcards
saltation
bounced along sea bed
traction
rolled
how do headlands and bays form
- when there are alternating bands of resistant and less resistant rock along a coat
- less resistant rock erodes faster forming bay with gentle slope
- resistant rocjk erodes slowly a juts out - healand with steep sides
how do headlands and bays erode to form caves, arches and stacks - OLD HARRYS ROCKS
- waves crash into cracks in headland - HYDRAULIC ACTION and ABRASION
- repeats and enlargens the cracks - CAVE
- repeats and cave deepends until it breaks through headland - ARCH
- erosion til arch collapses - STACK
wave-cut platforms
- waves hit cliffs and most power at the bottom - ccausing a notch (indent into cliff)
- waves repeat and this becomes unstable and so everything on top of the notch falls through - wave cut platform
how are sand and single beaches formed
constructive waves:
- sand - low energy waves - flat and wide
- shingle - high energy waves - steep and narrow
how are spits formed
- LSD takes sand past bend at headland and deposits it in the sea
- strong winds and waves make it bend - curve spit
- area behind - sheltered - salt marsh
how are bars formed
- spit joins 2 headlands together
- the bay behind this gets cut off from the sea
- lagoon forms behind the bar
how are sand dunes formed
- sand from LSD is moved up the beach by winds
- obstacles like driftwood get in the way – embryo dunes - marram grass grows
- ## mature dunes - more stable further back
types of soft enginering coasts
- beach nourishment - sand from elsewhere added - wider and make waves go slower - v££ and kills animals
- dune regeneration - creating sand dunes - stabilises the beach and cheap -
types of hard enginerring coasts
- sea wall
- gabions - wire cage of rock
- rock armour - boulders piled up
- groynes
hows a waterfall formed
- soft rock erodes faster than hard rock HA and abrasion - STEP
- water flows over step - more soft rock erodes - steep drop - WATERFALL
- hard rock erodes and collapses - UNDERCUT
- rock swirled around at bottom - PLUNGE POOL
- over time more undercutting - STEP SIDED GORGE
how are interlocking spurs formed
- upper course step sided v-shaped valley
- river is low energy - goes around the hard rock
whats a hydrograph used for
how the discharge at a certain point on the river changes over time in relation to rainfall
what is the river discharge
volume of water flowing per second
types of hard enginering rivers
- dams and resivouirs
- channel straightening
- embankments
- flood relief channels - river guided to area of flood plain not near houses
types of soft engineering rivers
- food warnings and prep
- flood plain zoning - stop ppl building on flood plains
- plant trees
- river restoration - remove any man made stuff from river like leeves
how are meanders formed
- current fast on the outside bend bc deeper - less friction to slow it down
- more erosion on outside - river cliffs
- slower on inside - shallower
- eroded material deposited on the inside - slip off slopes
how are ox bow lakes formed
- outside bends get closer
- river breaks through and water flows down the fastest route
- deposition cuts off bend of meander - this is ox bow lake
hows a flood plain formed
- when river floods the water slows down and loses energy and deposits material that its transporting - flood plain
how are levees formed
- natural embankments along the edge of the river
- when flooding happens material deposited onto the edges which build up - leeve
what are estuaries
- these are at rover mouths closest to sea
- tidle water - rises and falls each day
- over time mud builds up - mudflats
