rivers Flashcards
weathering
the breakdown and decay of natural processes acting on rocks, on cliffs and valley sides
freeze thraw
rocks breaking up from repeated freezing and weakening
chemical (acid rain)
when the rocks are near a very polluted place and acid rain occurs the droplets weaken the minerals in the rocks dissolving them
mass movement
the movement o a material down a slope due to gravity
abrasion
rivers glaciers or waves picking up sediments and rubbing against rocks in the bed and banks valley or cliffs
attrition
particles carried by rivers or waves are worn down as they collide with each other so they become smaller and rounded
channelisation
the deepening and/or straightening of a river to allow it to carry more water
confluence
a point where two rivers meet
deposition
sediments are dropped by the river, glacier or waves that carried them
discharge
volume of water flowing in a river measured in cubic metres per second
embankment
an artificial bank raised above the immediately surrounding land to redirect or prevent flooding by a river, lake or sea
erosion
the wearing away and removal of material by a moving force, such as a river, a breaking wave or a glacier
flood plain
the flat land in the valley floor each side of a river channel, which is sometimes flooded
ground water
water stored underground in rocks and soil
hard engineering
strategies using artificial structures e.g concrete to prevent river or coastal flooding
hydraulic action
this results from the sheer force of moving water wearing away the river bed and banks, or waves wearing away sea cliffs
infiltration
the process whereby water soaks into the soil and rock
lateral erosion
erosion where a river cuts sideways into its banks
levee
a raised bank of sediment along the side of a river
long profile
the shape and gradient of a river bed from source to mouth
meander
a bend formed in a river as it winds across the landscape
mouth
the point where the river leaves its drainage basin and reaches the sea
plunge pool
a hollow under a waterfall created by erosion and filled by water
point bar
sediment laid down on the inside of a meander bend where the river flows slowly
reservoir
a large lake usually artificial, used to store water
rip rap
large boulders of resistant rock placed at the bottom of cliffs that dissipate wave energy
river cliff
a steep section of river bank, caused by fast flowing water eroding the outside of a meander
saltation
where sediment is transported by being bounced along a river bed or sea floor
sediment
material such as mud, sand and pebbles carried and deposited by rivers or waves
sediment load
the sediment particles carried by a river
soft engineering
flood defences that work with natural processes to reduce the risk and impact of coastal or river flooding
solution
the process where some rock minerals slowly dissolve in water, which is slightly acidic
source
the starting point of a stream or river, often a spring or lake
traction
the transport of sediment along a river bed or the sea floor through a rolling action
transportation
the movement of sediment by rivers, glaciers or waves
tributary
a stream or small river that joins a larger one
velocity
the speed at which a river or glacier flows; river velocity is often measured in metres per second
vertical erosion
downward erosion for example of the river bed
