Zusammenfassung der Ressource
Rivers GCSE WJEC
- Erosional river processes
- Abrasion
- As the river moves material
it comes into contact with the
wetted perimeter and wears
it away
- Attrition
- As material moves by the river carry it - it hits other
material and it gradually becomes rounder and
smaller.
- Solution
- Acids in the river water dissolves soluble
parts/elements of the river banks.
- Hydrochloric Action
- The sheer force and pressure of the river water moves
material and dislodges it from the wetted perimeter.
- Depositional Landforms
- Slip off slopes
- The inside bend of a meander.
- Meanders
- Outside bend: river cliff Inside bend: slip off
slope. The river has less energy on the inside
of the bend and starts to deposit material.
- Ox bow lakes
- Outside of meander is thalweg, inside
is a slip off slope. - Increased erosion
of meander neck - River flows in
meander and straight through new
channel (very straight) - drying up ox
bow lake [water, lots of vegetation
will become land]. - Will eventually
start to meander again, rivers are not
naturally straight.
- Deltas
- Need low energy environment and
river material not wasted away
- Can
happen at
sea/ocean,
lake or
other rivers
- Transportation Techniques
- Traction
- Rolling of large
materials along the river
bottom
- Needs lots of energy
- Saltation
- Sand sized particles hop
along river bottom
- Suspention
- Silt and clay particles are carried
suspended in the water.
- Solution
- Some minerals are
dissolved in the river.
- Erosional Landforms
- Waterfalls
- Need hard rock
and soft rock
under a river.
- Waterfalls are
formed when the soft
rock erodes fastest.
- Soft rock eroding more creates
plunge pool and overhang forming
a waterfall.
- Overhang
collapses into
plunge pool
eventually over
time creating a
gorge.
- V shaped valleys
- Water always runs to the
lowest point and collects.
- This forms a channel
- Over time it erodes downwards cheating a V shape
- Does not have enough
energy to erode all the
slopes so it moves
around them
- Interlocking spurs
- *see V shaped valleys*
- Tourism at Niagara Falls
- YORK floods
- 2000
- 2012