RIVER LANDSCAPES - UK Flashcards
What is a river drainage basin
The area drained by a river and its tributaries
What is river erosion
The wearing away of the land by river
What is river deposition
The depositing of material carried by the river
What is a watershed (river)
The area of high land surrounding the river drainage basin
What is the river source
Where the river begins high up in the mountains
What are tributaries
Small streams that feed into the main river
What is a river confluence
Where two or more tributaries meet together
What is a river channel
The main body of the river in which the water flows
What is the river mouth
Where are river ends as it meets the sea or a lake
Name features of the upper course of a river
Rapids
Large boulders
Interlocking spurs
Waterfalls
Fast flowing water
Vertical erosion
Tribute trees
Source of the river
Narrow V shaped Valley
Gorges
Name features of the middle course of the river
Large meanders
Wide floodplains
Oxbow lakes
Raised banks caused by flooding (levees)
River starts to meander
Deposition
Wider, less steep U-shaped valley
Lateral erosion
Name features of the lower course of the river
Very wide flat Valley
River at its lowest
Industry and ports are found here
How many processes of erosion are there
4
Name the 4 processes of erosion in a river
Hydraulic action
abrasion
Attrition
Solution
What is hydraulic action
The sheer force of the water hitting the banks and riverbed causes rocks to be gradually removed by the river
What is abrasion
The process by which the bed and banks are worn down by the rivers load
The river throws these particles against the bed and banks at high velocity
What is attrition
Material carried by the river (the load)
Bumping into each other and so are smoothed and broken down into smaller particles
What is solution (river erosion)
The chemical action of the river water
The acids in the water slowly dissolve the bed and the banks particularly limestone
What is discharge in a river
The amount of water in the river
How is a V shaped Valley formed
1) river is Eroded downwards as builders, stones and rock particles are bounced and scraped along the channel bed
2) As the river cuts down the steep sides are attacked by weathering. This breaks up and loosen the soil and rock
3) The Loose material slowly creeps down the slope because of gravity or is washed away by river water and the river carries it away
4) The end result is a steep Sided valley that has the shape of a V
How was the waterfall formed
1) A river flows over the hard rock layer which is on top of the soft rock
2) The plunge pool is created at the base of the water where the water flows after running off the hard rock
3) Because it is soft rock it is eroded more easily than the hard rock
4)As the plunge pool grows, it undercuts the hard rock leaving an overhang
5)The overhang of rock is unsupported and eventually becomes a week and falls into the plunge pool
6)This process is repeated
7)Over many years the waterfall begins to retreat as the soft rock keeps being eroded and hard rock keeps falling down
8). Due to the repeat of this process, a gorge is created - Very steep vertical valley

Give an example of a waterfall retreating and it’s gorge
Niagara Falls retreats 1 m per year
It’s gorge is 7.1 miles long
What is a rivers bedload
The material carried by river as it moves
Why does the bedload/material get smaller as and rounder downstream
Attrition
What is the rivers capacity
The maximum volume of load that a river can carry at a specific point in its course
What is the rivers competence
The biggest sized particle that a river can carry at a specific point
How many types of transportation do rivers use
Four
Name the four types of transportation of river uses
Traction
Saltation
Suspension
Solution
What is traction
The largest rocks in the river are rolled slowly along the bottom of the river
What is suspension (type of transportation)
The water carries smaller particles of material
What is saltation (type of transportation
Smaller rocks are bounced along the river bed
What is solution (type of transportation)
Material is dissolved within the water and carried along
Why does deposition happen
When the water in the river channel no longer has sufficient energy to move into
Where does deposition happen in rivers
Inner bend of meander
On the floodplains
At the river
What is it called when the water in a river flows in a spiral / corcscrew motion?
Helicoidal Flow
What is the fast pest flow of a river called?
The thalweg
In a straight river where is the thalweg?
The middle
What happens on the outside of a meander bend?
The water is moving fastest here meaning it has more energy and therefore erodes the river bank
What happens to the inside of the meander bend?
The water flows the slowest meaning it has less energy and deposition occurs
How is the river bank on the outside of the meander bend eroded? And what does it create?
Undercut by lateral erosion usual by hydraulic action, creating a river cliff
What is the name given for the slope where the sand and shingles are deposited?
The slip off slope
Definition of an oxbow lake
A horseshoe or semi circular area that represents the old course of a meander
How was an oxbow lake formed
1) The meanders are formed naturally but get bigger because of the erosion of the riverbanks, caused by hydraulic action
2). (The narrowing of the neck of the meander)
As the fastest flow is on the outside of the meander, the outside of the band gets eroded quickly, the neck of the meander gradually becomes more eroded by hydraulic action this becomes very narrow and is separated only by a small piece of land!
3) (the neck of the meander is eroded through)
When water levels are high the river has enough energy to push through/straight across the small piece of land to make an easier course. Amy and a cut off it’s produced. The breaking through of the river often happens during times of flood particularly when the water is more powerful
4) (An oxbow lake is formed)
the small piece of land is eroded away or broken three and then the river starts off once again in a straight channel leaving the band isolated from the rest of the river. This is known as an oxbow lake
This link often dries up as it is no longer supplied with river water
Where is the River Tees located
In the north-east of England
The source is high in the Pennine hills Near Crossfell
Flows east 137 km to reach the North Sea at Middlesbrough
What is the name of the reservoir along the River Tees
Cow Green reservoir
What river forms are found in the upper course of the River Tees
The sauce
Carol Green reservoir
High Force waterfall
Interlocking spurs
What is the name of the waterfall along the River Tees
High Force waterfall
What is significant about the village Yarm Along the River Tees
Yarm is built on the inside neck of the meander and it is clever because it meant that Yarm was used as an inland port because it was accessible for boats,
They knew it would never get eroded away because it was built on the inside bend where only deposition was taking place.
How long is high Force Waterfall gorge
700 m
What did Stockton-on-Tees do to be successful
They built a bridge stopping boats from getting to Yarm, Making them the port as they are close to the estuary of the river
What is the estuary of the River Tees used for
Industry and chemical works are built along the history of the tees because it is easily accessed by boats without having to channelise the river
What are the five key factors that lead to a high or low flood risk?
Infiltration
Permeable
Surface run-off
Interception
Impermeable
What is infiltration (flood risks)
Water soaks into a permeable surface like a sponge
What is surface run-off (flood risks)
Water flows over the impermeable surfaces as it cannot infiltrate
What is interception (flood risks)
Water is caught on the leaves of vegetation
70% of rainwater is called by vegetation
What is a permeable surface (flood risk)
Water can infiltrate a permeable surface
Reduces flood risk
What is an impermeable surface (flood risk)
Water cannot infiltrate and impermeable surface e.g. concrete tarmac
Increases risk of flooding
Does frozen ground create a high or low flood risk
High
As frozen ground becomes an impermeable surface so little/no infiltration and more surface run-off takes place
Does saturated soil create a high or low flood risk
High
If the ground becomes too saturated due to lots of water it will not be able to infiltrate and therefore higher risk of flooding
Do you cities and towns create a high or low risk of flooding
High
Lots of impermeable surfaces so little or no infiltration and lots of surface run-off into drains leading straight to rivers
What a storm hydrographs
Following precipitation, there will be an increase in the level and discharge of the rain
This relationship between precipitation and discharge is shown by storm flood hydrograph
What does the rising limb tell us on a typical storm/flood hydrograph
The effects of precipitation reaching the river
What does a typical falling limb on a storm/flood hydrograph tell us
Some rainfall reaching the river but its decreasing amounts (the river returning to normal base flow)
What does the lag time show us on a typical storm/flood hydrograph
The difference between the time of heaviest (peak) rainfall and the peak discharge
What is the peak discharge on a storm/flood hydrograph
The maximum level/volume of water in the river
If the hydrograph has a short lag time and a steep rising limb what does it tell us about the flood risk
There’s a greater flood risk
If there is a lower flood risk what will a hydrograph look like for this flood
The lag time will be longer and the rising limb will increase gentler
What is hard engineering
Using man-made structures to prevent or control natural processes from taking place
Why would we use hard engineering strategies
To protect expensive property or land as it is usually a long-term solution and reliable however it is very expensive
Name 5 flood prevention hard engineering solutions
Artificial concrete levees
Artificial levees of sandbags
Flood relief channels
Straightening rivers course
Dams and reservoirs
Name 4 Soft engineering options for protecting against flooding
Afforestation = Planting belts of trees And vegetation
Floodplain zoning = Shows developers where they are allowed to build certain things to prevent industry and housing being built in floodplains are you at risk of being flooded
Flood warnings and preparation= Sending out warnings to people
River restoration= Removing hard engineering so it can go back to its natural channel
Why do we use soft engineering
Does not involve building artificial structures and therefore has less effect on the environment
What part of the river is Tewkesbury located at
The confluence of the river Avon and the river seven
Has the flood management scheme in Tewkesbury been successful
No
