Key words:
● Long profile = the gradient of a river as it journeys from the source to the mouth
● Cross-profile = a section taken sideways across a river channel/valley
● River channel = area occupied by the river/where the river flows
● River valley = overall shape of the valley landscape on either side of the river channel
● Discharge = volume of water passing through a given point (measured in cumecs, m 3 /sec)
● Velocity = speed of the river
● Tributary = smaller river which joins a larger river
● Confluence = point where 2 rivers meet
● Source = where a river starts , usually in high areas
● Mouth = where a river meets the sea
● Drainage basin = area of land drained by a river and its tributaries
● Watershed = edge of the basin within which water is collected
● Water-table = level below in which the ground is saturated with water
Long profiles:Looks at height/gradient (steepness) of river changes from source → mouth
○ eg/ River Severn → travels 354 km from source to mouth
■ Source = Plynlimon Hills, Cambrian Mountains
■ Mouth = estuary in Bristol Channel
● Rivers try to achieve a smooth curve in order to reach its
base level at sea
○ Gradient falls steeply at first
○ Becomes concave
○ Becomes almost flat
River’s journey from source to mouth:
Discharge and velocity:
● Discharge = volume of water passing through a given point (measured in cumecs, m 3 /sec )
○ Increases downstream as tributaries join the main river
■ Discharge = velocity x cross sectional area
● Velocity = speed of river
○ Increases along its course
○ Depends on how much water comes into contact with channel’s banks and beds
■ Upper course → small channel = large amount of friction
■ Lower course → broad, deep channel = small amount of friction
● More water = less water in contact with river bed = less energy used to overcome friction = high velocity
○ Speed is boosted by additional discharge from tributaries