Geography Rivers and Courses

confluence

confluence

point at which two rivers join

tributary

a river which joins a larger river

watershed

boundary dividing one drainage basin from another

hydraulic action

fast flowing water is forced into cracks breaking apart the river bank over time

solution (ersosion)

alkaline rocks such as limestone are dissolved by acidic rainwater

attrition

the wearing away of the rocks which are in the river as they knock together

abrasion

when the waves throw sand, pebbles ad sometimes boulders against a cliff face

saltation

pebbles bouncing along the river bed

solution (transport)

the transport of dissolved chemicals

suspension

tiny particles of material carried within the water

traction

large stones dragged along the river bed

drainage basin

the area of land around a river

thalweg

the fastest flow in a river

helicoidal flow

the corkscrew-like flow of the water

infiltration

water going into the ground

groundwater flow

excess water going up to the surface because the ground in saturated

throughflow

water flowing downhill into the soil

levees

a raised bank formed on the banks of a river due to the build up of sediment

floodplain

an area of low lying land prone to flooding

lag time

period between a rainfall event and a river’s peak discharge

peak discharge/flow

maximum discharge in the river

peak rainfall

maximum rainfall in an event

back flow

the normal day to day discharge

falling limb

represents the falling flood water in the river

rising limb

represents the rising flood water in the river