EQ4(4.6,4.7,4.8) Flashcards
What is meant by the long profile of a river?
The long profile of a river is the gradient of the river starting from the mouth to the sea.
Why are there changes in the stages of a river Upper-middle-lower?
Upper= Steeper gradient but more discharge and Slower water velocity due to rocks in the river .
Middle = slower and more meanders more lateral erosion .
Lower =steeper , wider and slower water velocity .
Compare hydraulic action and suspension .
Hydraulic =hitting banks , high velocity but suspension is when rocks are light enough to be suspended in water . These 2 can work together.
Define weathering.
Weathering is a process in which anything is worn down or eroded through weather processes .
Compare freeze thaw weathering to biological weathering .
Freeze thaw weathering is when water is got into the crack of a rock and then it freezes over night and expands and breaks . This puts pressure on the crack meaning erosion .
Biological weathering is when a sapling goes into a crack and grows as its roots add pressure on the rock and erodes it over time .
Compare traction and suspension .
Traction is when rocks are rolled across the sea bed floor and suspension is when rocks are suspended in water .
Waterfall formation ?
- More resistant rock lies over less resistant rock .
- less resistant rock erodes first through abrasion and hydraulic action .
- collapse of the less resistant rock means further erosion of the less resistant rock .
- the rivers load swirls at the bottom of the waterfall and erodes the bottom forming a plunge pool
- The more resistant rock overhangs and collapses
- this repeats meaning the waterfall goes downstream creating a gorge .
Ways climate , geology and slope processes effect river landscape .
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Key features of a flood hydrograph.
Peak rainfall - the heaviest rainfall occurred
Peak discharge - the time
Lag time -the time taken between the peak rainfall and peak discharge .
Rising limb -the river level rising .
Falling limb - the river level falling
How do (geology , soil,slope,basin type ) effect flood hydrographs.
Large basins receive more precipitation than smaller if the soil is compressed there is increased surface run off as well.
How and what human factors effect flood hydrographs (urbanisation , land use , deforestation )
Impermeable concrete
Deforestation means no roots and interception use of farms mean less woods and compressed soil.
How did physical and human effects effect flooding in the river eden .
Why is the floodrisk
Why is flood risk increasing in the uk ( global warming an human factors ).
Human urbanise areas making cities meaning impermeable concrete .
Farms with sheep compress soil and graze meaning more surface run off and less interception
Compare soft and hard engineering .
Soft engineering is generally cheaper and works with the environment it is also more sustainable .
Hard engineering is very expensive and not very sustainable but could be more effective than
What is good and bad about soft engineering .
Soft engineering is natural and more eco friendly than hard engineering . However it is arguably less effective . And also works with nature .
