Rivers Flashcards
Factors that effect the amount of discharge
Rainfall - type and amount Temperature - hot or cold Previous weather - wet or dry Relief - steep or gentle Rock type - permeable or impermeable Land use - rural or urban
Velocity
Speed of the river measured in meters per second (m/s). Increases from the source to the mouth because the discharge increases meaning there’s less friction from the bed and banks. Water is able to flow faster even though the gradient becomes gentler.
River erosion - hydraulic action
the sheer force of the flowing water on the bed and banks
River erosion - abrasion
Stones carried by the river wear away the channel (sandpaper effect)
River erosion - attrition
Stones collide, wearing them away, becoming smaller and rounder
River erosion - corrosion
Slightly acidic river water dissolves rocks made of calcium carbonate
Transportation - traction
Stones rolled long the river bed by the force of flowing water
Transportation - saltation
Stones bounce along the river bed
Transportation - suspension
Partials of slit and coat float in the water, making the river look cloudy
Transportation - solution
Minerals dissolve in the water
Upper course
Steep v-shaped valley and bedload is angular boulders and cobbles
Middle course
Erodes laterally and has gently sloping valleys. Bedload is round cobbles and pebbles
Lower course
Deposits to form a wide valley with a flat valley floor. Bedload is sand, slit and clay
Watershed
An area of higher land separating two drainage basins
Source
Where the river begins