river processes Flashcards
watershed
an area of high land forming the edge of a river basin
source
where a river begins
mouth
where the river meets the sea
tributary
a small river/stream joins a large river
confluence
the point where two rivers meet
channel
where the river flows
long profile
shows how the river changes over the course from the source to the mouth
upper course
where the river starts, usually an upland area. the river contains a lot of rock particles because it hasn’t been broken down by erosion
lower course
the final course of a river, land is flatter. the river carries fine sediment as rock particles have been broken down by erosion
cross profile
a view of a valley from one side to another
vertical erosion
land is eroded in a downward direction. a high river will erode vertically because gravity pulls the water down
lateral erosion
the wearing away of a landscape when a river erodes sideways
erosion
the process that wears away river beds and banks and breaks ups rocks that are carried in the river
type of erosion: hydraulic action
the sheer power of water as it smashes against river banks. air becomes trapped in the cracks in the rock of the river bank and bed, and causes the rock to break apart
type of erosion: abrasion
when pebbles are picked up by the flowing water and smash against the river bank and bed, wearing it away
type of erosion: attrition
when rocks that the river is carrying knock against each other. they break apart to become smaller and more rounded
type of erosion: solution
when the water dissolves certain types of rock, eg limestone
transportation
the river picks up sediment and carries it downstream
type of transportation: traction
large, heavy pebbles are rolled along the river bed. this is most common near the source of a river, as here the load is larger
type of transportation: saltation
pebbles are bounced along the river bed, most commonly near the source.
type of transportation: suspension
lighter sediment is suspended (carried) within the water, most commonly near the mouth of the river.
type of transportation: solution
the transport of dissolved chemicals. this varies along the river depending on the presence of soluble rocks.
deposition
when a river loses energy it drops material it carries
factors leading to disposition
- shallow water
- volume of water decreases
- at the end of the river’s journey, at the river’s mouth
