Zusammenfassung der Ressource
Geography: River Landscapes
- Path of a
River
- Upper
Course
- Steep
- Narrow,
shallow
channel
- Middle
Course
- Sloping valley
sides
- Wider, deeper
channel
- Lower
Course
- Very
wide
- Almost flat
valley
- Vertical
Erosion
- Deepens river valley and channel,
making it V-shaped. In the upper
course. High turbulence causes
the rough particles to be scraped
along the river, causing
downwards erosion.
- Lateral
Erosion
- Widens river valley and
channel during the
formation of meanders.
Middle & lower course.
- Processes of
Erosion
- 1
- Hydraulic
Action
- Force of the water
breaks rock particles
away from the river
channel.
- 2
- Abrasion
- Eroded rocks, picked up by
the river, scrape against
the channel, wearing it
away.
- 3
- Attrition
- The eroded rocks
smash into each
other and break into
smaller pieces. The
further material
travels, the more
eroded it gets.
- 4
- Solution
- River water dissolves
some types of rock -
E.G. Chalk and
limestone
- Transportation
- Solution
- Soluble materials
dissolve and are carried
along.
- Suspension
- Small particles
are carried along
by water.
- Saltation
- Pebble-sized particles are
bounced along the river bed by
the force of the water.
- Traction
- Large particles are
pushed along the
river bed by the force
of the water.
- Hard & Soft
Engineering
- Hard
- Man-made structures
built to control flow of
rivers and reduce
flooding.
- Embankments - Raised
walls built along the
river banks.
- + River can hold more
water so it will flood less
frequently, protecting
buildings.
- - A risk of severe
flooding if the water
rises above the level or
if they break. - Quite
expensive
- Channel Straightening -
River's course is
straightened
- + Water moves out
of the area more
quickly
- - Flooding may happen
downstream instead, as
water is carried there
faster and more erosion.
- Soft
- Flood
Warnings
- + Impact of flooding is reduced
+ People can evacuate
- - People may not
hear/access the
warnings.
- Schemes set up to
reduce the effects of
flooding
- Planting Trees -
Increases interception
of rainwater and
increases the lag time.
- + Discharge and flood risks are reduced
+ Vegetation reduces soil erosion
- - Less land is
available for farming
- Rivers Flood due to
Physical and Human
Factors
- Heavy
Rainfall
- Prolonged Rainfall
- Long Period of
Rain
- Relief - Change in
the Height of the
Land
- Geology