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River landscapes and processes . Geography CCEA GCSE 2009. The earth’s crust is modified by fluvial processes which result in distinctive landforms . River Structure. Stages in the Development of a River Valley. The river cuts downward to form a ‘V’shaped valley. The river starts

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River landscapes and processes l.jpg

River landscapes and processes

Geography CCEA GCSE 2009



Slide3 l.jpg

River Structure result in distinctive landforms


Stages in the development of a river valley l.jpg

Stages in the Development of a result in distinctive landforms River Valley


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The river cuts downward to result in distinctive landforms

form a ‘V’shaped

valley.

The river starts

to meander


What happens next l.jpg
What happens next? result in distinctive landforms


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River uses its meanders to cut from side result in distinctive landforms

to side eating into

the valley

Floodplain

starts to

form

1

2


What happens next8 l.jpg
What happens next? result in distinctive landforms


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1 result in distinctive landforms

2


What happens next10 l.jpg
What happens next? result in distinctive landforms


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Floodplain result in distinctive landforms

River bluffs

Alluvial

deposits

River cliff


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River Processes result in distinctive landforms

A river process is something that happens in the river. The main processes in the river are

Erosion - where parts of the river bed and bank get eroded / removed from the landscape

Transportation - where the eroded material is carried from one place to another through the river system

Deposition - where the river load becomes too heavy for the river to carry and is dumped down / deposited.


A river can erode material from its bed and banks in 4 main ways l.jpg
A river can erode material from its bed and banks in 4 main ways

  • Abrasion – Moving water throws particles it is carrying against the bed and banks of the river which dislodges more material

  • Hydraulic Action - The sheer force of the water pounding into the bed and banks can dislodge material

  • Attrition - Particles being carried downstream knock against each other, wearing each other down. This results in smaller, rounder particles as you move downstream

Use your text book to see if you can find the 4th type!


Methods of erosion l.jpg
Methods of Erosion ways

  • Abrasion –

  • Hydraulic Action -

  • Attrition -

  • Solution-


Methods of transportation l.jpg
Methods of Transportation ways

  • Rivers transport material in 4 main ways

  • Solution - Some minerals (particularly in limestone areas) dissolve easily in water and are not visible to the naked eye

  • Suspension – As the speed or velocity of a river increases, it is able to pick up and carry larger and larger particles in its flow. Where particles are carried along in the flow and are not in contact with the river bed, they are said to be travelling in suspension.


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Methods of Transportation ways

  • Saltation - Heavier particles may not be held in the flow all the time but may be bounced along the bed

  • Traction - The heaviest particles are rolled along the bed. Such particles may only be moved when the river has a large volume of water in it


Methods of transportation17 l.jpg
Methods of Transportation ways

  • Solution -

  • Suspension-

  • Saltation -

  • Traction -


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solution ways


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River Features ways

  • Rivers are eroding, transporting and depositing constantly within the drainage basin system.

  • The river can be divided into 3 sections – Upper Course at the Source, Middle Course and Lower Course at the Mouth of the river. The river displays different characterisitics at each section


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How to take notes on each of the River Features! ways

Course: Upper / Middle / Lower

Feature: Eg Waterfall

Diagram to illustrate: (make sure that this is labelled!)

Notes to explain how the feature happens:

Example of this feature:

Make sure that you take a new page for each new feature!




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How are v shaped valleys formed l.jpg
How are V-shaped valleys formed ?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426


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Use this sketch to help explain how they form http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

Vertical abrasion


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Upper Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

Also known as ‘Torrent’ or ‘Youth’ stages

Interlocking Spurs

In the Upper Course, the river is fast flowing, but there is little water and load. The river is often called a stream and does not have the erosive power to remove the hillsides (spurs), but erodes downwards instead.

EROSION TYPE: Vertical and Headward


Waterfalls and gorges l.jpg

Waterfalls and Gorges http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426


Draw the stages in the formation of a waterfall explain in as much detail what is happening at 3 l.jpg

Draw the stages in the formation of a waterfallhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

Explain in as much detail what is happening at 3

3. What is happening here? (see next slide)


Slide41 l.jpg

Waterfall formation flashhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426


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USAhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

Canada

Case study:

Niagara Falls


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USAhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

Canada


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Canada Horseshoehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

750 meters


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52 meters highhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426


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American Bridal Fallshttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

330 meters


Both falls the falls help to produce hep l.jpg
Both falls…the falls help to produce HEPhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426


The falls erode back at a rate of 1 5 meters a year l.jpg
The falls erode back at a rate of 1.5 meters a yearhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426


Frozen falls l.jpg
Frozen Fallshttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426


20 million visit the falls every year l.jpg
20 million visit the falls every yearhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55027&Groupid=12426

Visitors !!!



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Hard Resistant Rock - Limestone removed to improve the look

52 meters

Weak Rock - Shale


Gorges upper middle course l.jpg

Gorges removed to improve the look (Upper & Middle Course)

Case study: Niagara Falls (USA and Canada)


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Upper Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Waterfall and Gorge 1

(OBLIQUE AERIAL VIEW)

EROSION TYPE: Vertical and Headward


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Upper Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Waterfall and Gorge 2

(PROFILE VIEW)

EROSION TYPE: Vertical and Headward


Use the niagara falls pictures powerpoint l.jpg

Use the Niagara Falls Pictures PowerPointhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Notes to be taken from Page 10 from the Green Connections books


Meanders l.jpg

Meandershttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


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1. Can you mark the fastest flow on this?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

2. What type of erosion do you think is happening?


Can you mark on this the fastest flow l.jpg

What is a meander?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

..can you mark on this the fastest flow?


Where do you think erosion would take place l.jpg

What is a meanderhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

… where do you think erosion would take place?


Can you draw a cross section x y l.jpg

What is a meander?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Can you draw a cross section x-y?


This is what a cross section through a meander looks like l.jpg

What is a meander?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

… this is what a cross section through a meander looks like


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Middle Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Also known as the ‘Mature’ stage

Meanders 1

(Aerial View)

Meanders are formed because the current swings to the outside of a bend and concentrates the erosion there. Deposition occurs on the inside of the bed where there is not enough energy to carry load.

EROSION TYPE: Lateral


Slide72 l.jpg

Middle Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Meanders 2

(Profile View / Cross Section X - Y)

EROSION TYPE: Lateral

This cross section clearly shows the eddy current (near ’X’) formed by the velocity of the river being concentrated on the outside of the bend. These UNDERCUT the bank causing the formation of a RIVER CLIFF. On the inside (NEAR ‘Y’), a SLIP-OFF-SLOPE is formed where current is too slow to carry any load.


This is what a cross section through a meander looks like73 l.jpg

What is a meander?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

… this is what a cross section through a meander looks like


Ox bow lakes middle course l.jpg

Ox- Bow Lakes http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426 (Middle Course)


Slide76 l.jpg

Can you annotate this photo graph ?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


Slide77 l.jpg

Can you annotate this photo graph ?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


Slide78 l.jpg

Can you annotate this photo graph ?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


Slide79 l.jpg

Can you annotate this photo graph ?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


What are flood plains and levees l.jpg
What are Flood Plains and levees?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Levees

Floodplain


What do you think might happen here l.jpg

What is Meander Migrationhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

…. What do you think might happen here?


Slide82 l.jpg

What is Meander Migrationhttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


Slide83 l.jpg

Middle Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Ox-Bow Lake 1

(Aerial View)

Ox-bow lakes are formed when two meander RIVER CLIFFS are being eroded towards each other. These will eventually meet, causing the river to then flow across the bottom of the diagram.

EROSION TYPE: Lateral


Slide84 l.jpg

Middle Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Ox-Bow Lake 2(Aerial View)


Levees l.jpg

Leveeshttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


Slide86 l.jpg

Leeveshttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

River


Slide87 l.jpg

Lower Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Leveés and Raised Beds 1(Front View)

DEPOSITION FEATURE: no erosion in the Lower Course

Leveés are formed when rivers flood. The river water overflows the banks of the river and immediately slows down due to friction with the FLOODPLAIN. This drops the larger particles first, building up a raised river bank called a LEVEÉ.


Slide88 l.jpg

Lower Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Leveés and Raised Beds 2(Front View)

DEPOSITION FEATURE: no erosion in the Lower Course

Raised beds form in the Summer months when the river volume and energy are low and load is dropped onto the river bed. The bed raises up and the capacity of the river reduces, causing flooding in the winter. This in turn builds up the leveés and the whole process raises up the level of the river in the landscape.


Slide89 l.jpg

Lower Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Braided Channels(Oblique Side View)

DEPOSITION FEATURE: no erosion in the Lower Course

In the Summer months, load is dropped by the low volume of low-energy water in the river. These build up to form obstructions in the river and it divides up to flow around them. In the winter, it is likely that the river volume will increase and remove these obstructions.


Deltas l.jpg

Deltashttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


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Lower Coursehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Delta(Aerial View)

This deposition feature is one of the largest. When the flowing river hits the non-flowing sea, energy is suddenly lost. This causes all of the load in the river to drop in the river MOUTH. This builds up over time to create a delta – an area of land. The river divides into DISTRIBUTARIES to continue to the sea, which is now some way away from its original meeting point.


Slide93 l.jpg

What's the Point of all This?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Can you work out what the river is trying to do by using this diagram?


Slide97 l.jpg

River Structurehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426


Slide98 l.jpg

What's the Point of all This?http://www.school-portal.co.uk/GroupDownloadFile.asp?file=55026&Groupid=12426

Can you work out what the river is trying to do by using this diagram?


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