Physical landscapes – River landscapes in the UK

Erosion

  

 

Abrasion or corrasion Attrition Hydraulic Action Solution or corrosion

 

 

 

 

__________________________________________________________________________________________________________ 

Describe reasons why a river’s energy decreases. ____________________________________________________________________________________________________________________________________________________________________________________________________________________

Deposition Why does deposition occur? 

The shape of river valleys changes as rivers flow downstream - PROCESSES

T______ S___________ S___________ S___________

Challenge: What is the Hjulstrom Curve?

 

EROSION TRANSPORTATION DEPOSITION

UPPER COURSE

    

   

MIDDLE COURSE

    

   

LOWER COURSE

    

   Where does most of the vertical erosion take place? Why?

Where does most the Lateral erosion take place? Why?

Explain what happens to the discharge and velocity as you more downstream.

 

Which processes are operating where?

How is a V-Shape Valley formed?

Upper / Middle / Lower?

Feature Description

  Floodplain

  Plunge pool

  Ox-bow lake

  Waterfall

  Meander

  V-shape valley

What are the features of a river?

UPPER

Upper, middle and lower - Draw, label and describe the formation of the features located along the

1.  2.   3.  4. 

MIDDLE

As water travels from the upper river section to the ____________ river section. There is less pull from __________, therefore there is less ____________ erosion and more _______________ erosion. The sideways movement of water causes it to flow___________ on the outside bend, as such the water has more __________ and erosion Takes place forming a ______________, the water slows down on the _______________ which means the water has ____________ energy, and so ____________ occurs forming a ____________________.  

Missing words: Gravity, Middle, lateral, vertical, energy, faster, inside bend, River Cliff, deposition, less, slip-off slope.

Lower – Floodplains and LevéesFirstly, floodplains are formed by a combination of both __________ (where land is worn away) and ____________ (where sediment is laid down by the river) processes. _________ erosion (where the river erodes from side to side across the floodplain) has the effect of ___________ the floodplain over hundreds of years. Deposition is also important. When the river ________, it spreads out over the floodplain. Next, this slows the river down as the river is in contact with more __________. This causes deposition of __________, the __________ rocks and most of the sediment is dropped closest to the river channel, the finer material is dropped ________ away. Finally, this creates a _________ floodplain and levées.

Words to use: widening, deposition, floods, Lateral, levees, friction, largest, erosion, further, sediment, layered

Casestudy – River Tees, an example of a river valley • To know an example of a river valley in the UK to identify its major landforms of erosion and deposition.

• To know named Erosional and depositional features along the River Tees

• To be able to explain how these landforms were formed

Using your notes and research online - Add detailed notes about all of the landforms and processes and human interferences with the river occurring whilst the video plays along the Tees from source to mouth.

Human Causes p166-167 Physical Causes p164 - 165

Causes of flooding

Title: ___________________________________________ What is a storm hydrograph? ____________________________________________________ ________________________________________________________________________________________________________ Graph definitions Base flow – Rising limb – Peak discharge - Falling limb – Lag time – Why are storm hydrographs important? ____________________________________________________________________________________________________________________________________________________________

The shaded area is known as the ___________ ___________

Different factors can affect the shape of a storm hydrograph and affect its lag time:Vegetation Geology Rainfall Land use Relief

Hard and soft engineering of river environments   Definition Scheme How it works Diagrams or examples Costs (negatives) Benefits (positives)

Hard en

gine

ering

  Dams and reservoirs

  

Straightening meanders  

      

     

Embankments

Flood relief channels

Soft eng

inee

ring

  Flood Warnings and preparation

   

   

Flood plain zoning      

   

 

  

  

 

   

 

    

Land uses increase in value as distance from river increases

Effects Social impacts Economic impacts  

The cost for Insurance for houses and business went up. 

Damages could be over £10 million. 

400 residents were evacuated. 

Morpeth High Street was under 60cm of water. 

Farming losses were estimated at over £1million. 

The library suffered severe structural damage due to the heavy debris transported by the river. 

More than 1,000 houses were affected. 

Emergency services involved in rescue and recovery operations 

Causes of the 2008 flood

HUMAN PHYSICAL - Flood defences schemes

failed because the discharge was larger than the channel could contain. If flowed over the walls.

Evaluation of the management:

Previous floods protection failed: Walls built after the floods in the 1960s but failed and in 2008 the town flooded causing £10 million of damage.

New scheme was expensive and they ran out of money: New scheme put in place included new walls and dam – cost £26.5 million. Considered expensive – half funded by the council and other Environment agency. They ran out of money and were short £1.5 mill.

Environmental concern: The new scheme put in place threaten habitats such as the cray fish. (Evaluation – did lead to them being protected).