evolving landscape - rivers Flashcards
source definition
where a river starts - usually high hills, V shaped valleys
mouth definition
where river ends - on the coast, flowing slow and wide in between flat valley
tributary definition
stream/river that flows into a mainstream/parent river
confluence definition
meeting of two or more bodies of water - where tributary meets mainstream river
watershed definition
line that separates drainage basins - runs along geographical barrier between drainage basins
drainage basins definition
area which is drained by a river and its tributaries
4 methods of erosion
attrition
hydraulic action
abrasion
solution
what is attrition
rocks being carried by river that smash into each other - become small, rounded, smoother particles
what is abrasion
rocks and the load rub against the banks of the river - causes bank material to break and eventually collapse
what is hydraulic action
force of river against the bed and banks causes air to be trapped in the cracks and crevices - pressure weakens the material and wears it away
what is solution
soluble particles dissolved into the river
what is vertical and lateral erosion and where do they occur on a river
vertical erosion - downwards erosion and usually at the upper course of a river
makes a V shaped valley - gradient is steep and river flows quickly
lateral erosion - sideways erosion and usually at the lower course of a river
makes a broad/flat valley - gradient is gentler, volume is higher, speed of flow is slow
4 methods of transport
suspension
traction
saltation
solution
what is suspension
lighter material suspended in the river - mostly at the mouth
what is traction
large rocks rolled over the river bed - mostly at the source
