coasts Flashcards
(river) source
where a river begins
(river) drainage basin
the area from the water drains into the river
(river) water shed
an imaginary line that separates two drainage basins
(river) confluence
the point where 2 rivers join together
(river) tribute /tributes
smaller rice s which join the main river
(river) floodplain
land that floods when rivers overflow
(river) mouth
where the river flows into the sea or lake
(river) river bed
bottem of a river channel
(river) riverbank
the side of a river channel
(river) channel
river flows in it
(river) abrasion
bed+bank are worn down by load
(river) corrosion
chemical action of river water
(river) hydraulic action
involves the force of water against bed + banks
(river) attrition
the load carried by the river bump into each other
(river) spurs
river meets areas of harder rock
it can’t cut through
instead wind around them
(river) tractions
larger heavy pebbles/ boulders rolled along the river bed
(river) saltation
pebbles bounced on the bed( near the source )
(river) suspension
lighter sediment carried in the water
(river) solution
transport of dissolved chemicals and minerals
(river) deposition
when a river looses energy and drops sediment
(river) thawlthag
line of fastest flow
(river) estuary
the tidal part of the river where the freshwater from the river merges with saltwater from the sea
(river) base flow
starting and finishing flow of the river either side of increased discharge
(river) peak discharge
max discharge following rainfall event
(river) peak rainfall
highest rate of rain during rainfall event
(river) lag time
time between peak rainfall + peak discharge
(river) rising limb
increasing discharge as storm water enters the river channel
(river) receding limb
fall in discharge back to base level
(river) meanders
the curve in the river by erosion and deposition
(river) capacity
max amount of things it can carry (overall weight of the load)
(river) competence
largest sized individual particle a river can carry (largest rock,not the total weight)
hydrogaphs way
rainful= always a barchart
discharge=always a line graph
hard engineering
involved building artificial structures which try to control nateral processes
disadvantages: more expensive, work against nature
advantages: greater impact
soft engineering
where the natural environment is used to help reduce coastal erosion and river flooding
disadvantage: less effective
advantages : natural, less maintenance
(coasts) coastline
a place at which land meets the seas
(coasts) weathering
the breakdown of rocks at the earth surface by the action of rain water extreme of temperature + biological weathering
(coasts) wave
a body of water moving towards a coastline at a higher than average level
(coasts) attrition
material carried by the wave bump into each other and so are smoothed and broken down into smaller particles
(coasts) hydraulic action
this process involves the force of water against the coast
the waves enter cracks in a he coastline and compress the air in crack
wave retreats the air in the crack expands -> minor explosion
repeated
(coasts) corrosion
chemical action of sea water
the acid in the salt water slowly dissolve rocks on coast
limestone and chalk are particularly prone to process
(coasts) abrasion
the coast is worn down by material carried by the waves
waves through theese particles against the rock sometimes high velocity
(coasts) bay
area of less resistant (soft) rock between 2 headlands which is quickly eroded
(coasts) line of weakness
not smooth too me , lines of weakness are a weak link in the cliff
attacked thru erosion
(coasts) caves
processes attack line of weakness in cliff
get bigger + deeper
(coasts) arch
erosion of cave continues (corrosion attrition and hydraulic action)
extends all the way thru creates arch
(coasts) stack
weight of the roof collapses so stands alone
weathered away and creates stack
(coasts) stump
waves slowly erode stack forms a notch -> gets big and collapses leaving a stump
(coasts) longshore drift
the transport of sediment along a stretch of coastline caused by waves approaching the beach at an angle
(coasts) spits
a finger of land made of sand and shingle that extends into the sea from the coastline
caused by change in coastal direction
(coasts) wave refraction
as waves approach a coast they are refracted so that their energy is concentrated around headlands but reduced around bays
(coasts) bars
if a spit has grown across a bay and joined one part of the main land to another
(coasts) creep
sand movement that’s rolled along
(coasts) concordent
where bands of different rock type run parallel to the coastline
(coasts) discordant
layers of rock run at right angles to the coast
what does a rivera long profile show
the long profile shows how a rivers gradient changes as it flows from its source to its mouth
what’s the upper course of the river
the steepest part of the land in the river, small but flows quickly, energy levels are high and the river cuts away as its bed. as it does it quickly deepens its valley through down cutting which creates steep sided v shaped valley.
what’s the middle course of the river
river starts to flow slowly because it starts to transport lots of sediments as rivers look muddy. As the river moves down its valley a number of changes occur. The river gets wider as more tributes join together.
what are the 4 changes that ocur in the middle course
- the valley sides become less steep, giving the shape of a open v
2.the river begins to erode sideways into its bank. This opens out to the valley floor and a flood plain starts to develop
3.erosion and depositions occur - the edges of the floodplain are marked by bluffs
what is the lower course of a river
when the valleys v shape is so wide that the valley sides have been disappeared. The river approaches its mouth, The river now winds its way slowly across a large flood plain. Deposition is now the dominant process
define rock resistance
erosion rate increases more wrodible the rock is
define gradient
a steep gradient results in the river water being pulled by gravity, cutting down and eroding the channel
define artificial levees
where people bulls up the height of the bank (piled earth or coated in concrete) to limit the change of a river flooding
define competence
largest sized individual particles a river can carry = the largest rock it could move
