Rivers Flashcards
What is abrasion?
Rocks carried along by the river wear down the river bed and banks
What is attrition?
Rocks being carried by the river smashing against eachother
What is discharge?
The quantity of water that passes a given point within a given period of time
What is an estuary?
Where the river meets the sea
What are embankments?
Raised banks constructed along the river
What is flood plain zoning?
Separating land so that land that often gets flooded is not built upon
What is a flood relief channel?
Artificial channels made to increase discharge
What are fluvial processes?
Relating to erosion, transport and deposition of a river
What is a gorge?
A narrow steep sided valley
What is hard engineering?
Using artificial structures to strop, disrupt or reduce the impact of river processes
What is hydraulic action?
Air being trapped in cracks, this weakens the banks and wears it away
What are interlocking spurs?
A series of ridge projecting out on alternate sides of a valley
What is a levee?
Embankment of sediment along the bank of a river
What is saltation?
Particles bouncing down the river bed
What is soft engineering?
Using the natural enviroment and working with the. River
What is solution?
Soluble particles dissolving into the rivet
What is suspension?
Fine solid material held in the water whilst it is moving
What are the different stores of water?
Interception
Surface storage
Soil moisture
Groundwater store
What are the water transfers?
Stem flow
Infiltration
Percolation
Groundwater flow
Through flow
Surface run off
What is the water table?
Current upper level of saturated soil where no more water can be absorbed
What is ground water flow?
Water flow through the rock layer
What is through flow?
Water flow through the soil layer
What is percolation?
Water seeping deeper through the rock
What is a drainage basin?
The area of land drained by a river and its tributaries
What is a confluence?
Where a tributary joins a larger river
What is watershed?
The edge of a river basin
How mnay courses of a river are there?
3
How does the gradient of a river change from source to mouth?
Gets less steep
What landforms can you expect in an upper course?
V shaped valleys
Interlocking spurs
Waterfalls
What landforms can you expect in a middle course?
Meanders
Oxbow lakes
What landforms can you expect in the lower course?
Levees, flood plains, estuaries
What is traction?
Material rolled along the bed
What is load?
Material being carried by the river
What is deposition?
Material being transported by the river is dropped
What characteristics can you expect in the upper course?
Valley - steep
Channel - narrow
What characteristics can you expect in the middle course?
Valley - wider, less steep
Channel - wider, deeper
What characteristics can you expect in the lower course?
Valley - flat, wide
Channel - deep, wide
What processes and material can we expect in the upper course?
Mainly erosion
Load is large nad angular
What processes and material can we expect in the middle course?
Erosion and transportation
Load slightly smaller and rounder
What processes and material can we expect in the lower course?
Transportation and deposition
Load is small and round
How are interlocking spurs formed?
Vertical erosion creates a v shaped valley
Rivers lack lateral erosion so it is forced to wind around hillsides
How is a waterfall formed?
Water runs over alternating bands of hard and soft rock
Erosion wears away the soft rock
This starts to undercut the hard rock
This collapses into the river bed creating a plunge pool
This repeats and the waterfall retreats backwards
Leaving a gorge
What is the faster flow of water in a meander called?
Thalweg
What human factors can affect flood risk?
Deforestation
Urbanisation
What physical factors can increase flood risk?
Relief
Rainfall
Basin size
Rock type
Soil saturation
What are examples of hard engineering strategies?
Chanel straightening
Embankments
Flood relief channels
Dams and resiviors
What are some soft engineering strategies?
Flood warning + preparation
Flood plain zoning
Afforestation
Reviver restoration
Where does the jubilee channel effect?
Windsor
Eton
Wraysbury
How much did the jubilee river relief channel cost?
£110 million
What is the cost of repairing the channel after an episode of flooding?
£680,000
When was the jubilee river completed?
2002
What are some socioeconomic positives of the jubilee river?
3000 properties are protected
What are some socio economic negatives of the jubilee river?
Small business’s can’t open when they are flooded so they are under pressure
Most expensive flood relief scheme in the UK
Funding has now been withdrawn so the government only fund parts
What are some environmental issues of the jubilee channel?
The concrete weirs are ugly
The natural ecosystem has been effected
The Thames now experiences much higher flooding
What towns has the jubilee river helped?
Maidenhead
Windsor
Eton
What towns has the jubilee river negatively affected?
Old Windsor
Wraysbury
What are the positives of the jubilee river?
Protects 3,200 homes
Increases river capacity
Protects 500 businesses
What are the negatives of the jubilee river?
Business insurance now costs £500 million
Its an economic burden as it is very expensive to restore
Worsened flooding in Wraysbury
Eutrophication
Property price reduced by 20%
