The changes in a river gradient from source to mouth are shown in what type of profile?
Enjoying Flashcards?
Tell us what you think
The changes in a river gradient from source to mouth are shown in what type of profile?
The changes in a river gradient from source to mouth are shown in a long profile.
What is a cross-profile of a river?
A cross-profile is a section taken sideways at 90° to the river channel.
True or False?
The cross profiles of the upper, middle, and lower courses are the same.
False.
The cross profiles of the upper, middle, and lower courses show changes in the river channel. With distance, downstream rivers become wider and deeper.
Define the term erosion.
Erosion is the wearing away and removal of material.
Name the four processes of erosion within a river.
The four processes of erosion within a river are:
Hydraulic action.
Abrasion.
Attrition.
Solution.
True or False?
Vertical erosion is dominant in the lower courses of rivers.
False.
Vertical erosion is dominant in the upper course of rivers.
Materials bouncing along the river bed are what type of transportation?
The type of transportation where materials bounce along the river bed is saltation.
Define the term alluvium.
Alluvium refers to the lighter materials (gravel, sand, and silt) that are carried further downstream.
Describe the process of traction.
Traction is a type of transportation where the heavier bedload rolls along the river bed.
What causes deposition?
Deposition is caused by reduced discharge or velocity due to:
A lack of precipitation or abstraction upstream.
Decreased gradient.
Slower flow on the inside of a river bend or where the river is shallower.
The river entering a sea, ocean or lake.
What is the name for a valley with steep sides created by a waterfall retreating?
A gorge is a valley with steep sides created by a waterfall's retreat.
What are the steps in waterfall formation?
Waterfalls form where there is a drop in the river bed from one level to another. This drop is often due to changes in the hardness of the rock, where hard rock overlies soft rock. Hydraulic action and abrasion are the main erosional processes:
The soft rock erodes quicker, undercutting the hard rock and creating a plunge pool.
This leads to the development of an overhang of hard rock which eventually overtime, collapses.
The hard rock overhang falls into the plunge pool increasing abrasion and making the plunge pool deeper.
The process then begins again and the waterfall retreats upstream leaving a steep-sided gorge.
True or False?
Meanders increase in size in the lower course of a river.
True.
Meanders increase in size in the lower course of the river.
Define the term slip-off slope.
A slip-off slope is a deposit formed on the inside of a river bend due to deposition.
True or False?
Oxbow lakes form during normal flow conditions.
False.
Oxbow lakes form when the river breaks through the neck of the meander during a flood.
Define the term levée.
A levée is a natural embankment formed by the deposition of the heaviest material nearest to the river channel during flooding.
True or False?
The water flow on the inside bend of a meander is faster than the flow on the outside bend.
False.
The flow of water on the outside bend of a meander is the fastest. This leads to erosion and the formation of a river cliff.
Which landform in the river's upper course is the result of vertical erosion, weathering and mass movement?
V-shaped valleys are the result of vertical erosion, weathering and mass movement in the upper course of the river.
What is the line of the fastest water flow in the river called?
The line of the fastest water flow in the river is called the thalweg.
Define the term floodplain.
A floodplain is a flat expanse of land on either side of a river.
Located on the River Tees, what is the name of England's highest waterfall?
England's highest waterfall is called High Force.
Name the hard and soft rocks that led to the formation of High Force.
High Force was formed when dolerite, a hard igneous rock (known locally as 'whinstone'), was laid over the softer sedimentary rock, limestone
Which river landform is common in the area between Darlington and Yarm?
Meanders dominate the area between Darlington and Yarm.
Where is the source of the River Tees located?
The source of the River Tees is located on the Pennines at Cross Fell.
Define the term flooding.
Flooding occurs when the capacity of the river channel is exceeded, and water flows over the banks onto the surrounding area.
True or False?
A shorter lag time decreases the risk of flooding.
False.
A shorter lag time increases the risk of flooding because the water reaches the river more quickly, causing the discharge of the river to increase faster.
List four human factors that increase the risk of flooding.
Four human factors that increase the risk of flooding are:
Deforestation.
Urbanisation.
Agriculture.
Climate change.
True or False?
Steep slopes increase infiltration and decrease overland flow.
False.
Steep slopes decrease infiltration and increase overland flow.
Define peak discharge.
Peak discharge is the point at which the river flow is highest.
Dams and reservoirs are examples of what type of river management?
Dams and reservoirs are examples of hard engineering, where structures are built or the river channel is changed.
Give one advantage to river restoration.
Some of the advantages of river restoration include the following:
Increases the number of habitats.
Restores wetland areas .
Slows down water flow, reducing flooding downstream.
What is the name of the soft engineering strategy that restricts land use in areas at risk of flooding?
Floodplain zoning is the name of the soft engineering strategy that restricts land use in areas at risk of flooding.
What are the two main advantages of straightening river channels?
The two main advantages of straightening river channels are that it:
Speeds up the movement of the water over a short distance.
Allows easy navigation for boats.
What is Clifton Ings in York an example of?
Clifton Ings is an example of floodplain zoning. The area has been left as an open, undeveloped floodplain, which can store 2.3 million m3 of water.
What hard engineering strategies have been used in York to reduce the impacts of flooding?
The hard engineering strategies used in York to reduce the impact of flooding are:
Embankments (Leeman Road) increase the capacity of the river.
Floodgates at Marygate.
Flood relief channels at Acomb.
The Foss Barrier at the confluence of the River Ouse and the River Foss.
What was the cost of the Foss Barrier upgrade after the 2015 floods?
The cost of the Foss Barrier upgrade after the 2015 floods was £38 million.