There are three stages in the course of a river:
Upper Stage (Youthful stage)
Middle (Mature stage)
Lower (Old stage)
There are three important processes associated with rivers:
Erosion - the wearing away of the bed or banks of the river
Transportation - the movement of material within the river
Deposition - the dropping of material which is being transported
There are four methods of erosion:
Hydraulic action - the force of moving water
Abrasion - the wearing down of bed or banks with material the river is carrying
Attrition - the wearing down of material the river is carrying as a result of bouncing off each other
Solution - chemically eroding material with dissolved material in the water
Landforms
V- shaped valleys
Formed from vertical erosion and mass movement
Associated with the upper course
Eg.g upper stage of the Liffey
Interlocking Spurs
Formed from a series of bends in the upper stage of the river causing the adjacent valleys to interlock
Associated with upper course
E.g. River Slaney
Waterfall
Formed when a band of hard rock lies over a band of soft rock
Rocks are eroded at different rates causing a vertical drop
A plunge pool can form
Associated with upper course
The overhang can collapse
e.g Powerscourt waterfall
Meanders
A significant bend in a river
Formed from erosion AND deposition
The river will bend around an obstacle, over time the bend becomes more exaggerated
Erosion occurs on the outside of the bend, deposition on the inside
Associated with middle course
E.g. River Shannon
Oxbow lakes
Horseshoe-shaped lake cut off from a meanders
During a time of flooding the river cut off the meander by erosion taking a direct route
Deposition then occurred to seal off the old meander separating it from the course
Associated with middle course
E.g. River Liffey
Flood plains
Wide flat area adjacent to river course
Alluvium sediment deposited on this area during floods
Associated with the old stage
E.g. River Liffey
Levees
Raised edge on the bank of a river
Formed from floods depositing material at the edge of the bank
Associated with old stage
E.g. River Moy
Deltas
Fan-shaped area of sediment at the mouth of the river
Formed from deposition where the river splits in to distributaries
Associated with the old stage
E.g. River Nile
Upper Stage (Youthful stage)
Middle (Mature stage)
Lower (Old stage)
There are three important processes associated with rivers:
Erosion - the wearing away of the bed or banks of the river
Transportation - the movement of material within the river
Deposition - the dropping of material which is being transported
There are four methods of erosion:
Hydraulic action - the force of moving water
Abrasion - the wearing down of bed or banks with material the river is carrying
Attrition - the wearing down of material the river is carrying as a result of bouncing off each other
Solution - chemically eroding material with dissolved material in the water
Landforms
V- shaped valleys
Formed from vertical erosion and mass movement
Associated with the upper course
Eg.g upper stage of the Liffey
Interlocking Spurs
Formed from a series of bends in the upper stage of the river causing the adjacent valleys to interlock
Associated with upper course
E.g. River Slaney
Waterfall
Formed when a band of hard rock lies over a band of soft rock
Rocks are eroded at different rates causing a vertical drop
A plunge pool can form
Associated with upper course
The overhang can collapse
e.g Powerscourt waterfall
Meanders
A significant bend in a river
Formed from erosion AND deposition
The river will bend around an obstacle, over time the bend becomes more exaggerated
Erosion occurs on the outside of the bend, deposition on the inside
Associated with middle course
E.g. River Shannon
Oxbow lakes
Horseshoe-shaped lake cut off from a meanders
During a time of flooding the river cut off the meander by erosion taking a direct route
Deposition then occurred to seal off the old meander separating it from the course
Associated with middle course
E.g. River Liffey
Flood plains
Wide flat area adjacent to river course
Alluvium sediment deposited on this area during floods
Associated with the old stage
E.g. River Liffey
Levees
Raised edge on the bank of a river
Formed from floods depositing material at the edge of the bank
Associated with old stage
E.g. River Moy
Deltas
Fan-shaped area of sediment at the mouth of the river
Formed from deposition where the river splits in to distributaries
Associated with the old stage
E.g. River Nile