Rivers and their Valleys. What you will need to do.. that there are different rock types on the Earth’s surface how weathering and mass movement occur.

Rivers and their Valleys

What you will need to do.. that there are different rock types on the Earth’s surface how weathering and mass movement occur that the water cycle is the basis for studying both weather and rivers the three processes (erosion, transportation and deposition) which affect the landscape and how they are connected how a river changes from source to mouth the characteristics of weather associated with depressions and anticyclones the impact of weather conditions on selected land uses the conflict that can arise between land uses within river landscapes the solutions adopted to deal with the identified land use conflicts.

The rock cycle

Sedimentary Rocks

Igneous Rocks

Metamorphic Rocks

Summarise Using the sheets that you have been given – summarise: The Rock Cycle The Types of Rock and their characteristics

How On Earth Does This Car Link To Geography?

Objectives... To be able to explain the differences between the three types of weathering To be able to explain how weathering sustains life To be able to identify real-life examples of the three types of weathering

Three Types Of Weathering... Physical Biological Chemical

Task One... ◊ Decide which order the statements go in to produce a flow diagram of the process ◊ Cut and stick, or write out, the statements in the correct order in your book ◊ Draw a diagram illustrating each stage of each of the weathering process

To be able to explain the differences between the three types of weathering

Without Weathering You Would Die...!!!

To be able to explain how weathering sustains life

Venn Diagram Write the number of the pictures in the area of the Venn diagram which you think best describe the process occurring there Swap your sheet with another table, check if you agree with their answers

Mass Movements What’s the connection between this picture and the rock cycle Mass Movement is the down-slope movement of loose rock and soil due to gravity. Whilst processes such as soil creep are very slow, landslides can be very sudden, and may cause loss of life. Mass movement is often aided by water, so landslides and mudflows frequently occur after heavy rain.

There are two types of mass movement that you need to know about Soil Creep is slow – a few cm per year. Fences & walls lean over, trees bend as they grow. Grassland develops terracettes Mudflow and Landslide often happen after heavy rain. Lots of heavy rain can make top layers of soil saturated. Gravity takes over and the saturated layer moves downslope rapidly.

In Geography we say that the landscape is part of a system Inputs - things that go into the system, weather conditions, the action of the glacier or the sea, volcanic activity, the sea. Processes - the thing that happens in the middle as a result of the inputs: Weathering conditions cause the rocks to break up Lava from volcanic eruptions, mudflows etc.. Create new land Gravity causes mass movement Glaciers, Rivers and sea erode transport and deposit material. These all effect the landscape Outputs - these are the things that come out of the system. Task Describe how soil creep, muflows and landslides happen Choose two of the inputs and explain how you think they might shape the landscape.

Make a copy of this diagram….

Using Page 12 of GeogSG Create a word bank to give definitions of the words on your diagram

When a liquid turns into a gas.

When a plant takes up liquid water and releases it as a gas through its leaves..

When a gas cools and turns into a liquid.

The name given to water, in any form, that falls from the sky.

When water soaks into the soil.

Water that flows through the rocks underground.

Water that flows across the surface of the ground.

Water that flows in rivers… eventually into the sea.

5 min Test – see what you can remember Using a white board draw the diagram of the Hydrological Cycle Add labels

Starter - What do you think this organisation is for - why are all these countries involved

Drainage Basin

Your book A template A stick of glue Scissors Pencil crayons- blue and brown A pen

Cut out the template. Make sure you cut up the vertical line.

Using a brown crayon, shade around the circumference of the circle.

Using a blue crayon, shade the left triangle, draw some blue lines running from the top of the triangle and branching out towards the edge of the circle.

Watershed the area of high land forming the edge of a river basin. Source where a river begins. Mouth where a river meets the sea. Confluence the point at which two rivers meet. Tributary a small river or stream that joins a larger river. Channel this is where the river flows. Drainage Basin this is the area of land drained by a river and its tributaries. 1 You will now need a pen. Number the following features on your template. 2 3 4 5 6 7

Glue the remaining blank triangle.

Stick the glued triangle under the shaded triangle, so it fits neatly.

Open your book to a double page. Glue the triangle and the bottom sides of the diagram. Stick this firmly across the cease of the book. The tip of the triangle should correspond to the cease.

It should look like this!

Watershed the area of high land forming the edge of a river basin. Source where a river begins. Mouth where a river meets the sea. Confluence the point at which two rivers meet. Tributary a small river or stream that joins a larger river. Channel this is where the river flows. Drainage Basin this is the area of land drained by a river and its tributaries. 1 2 3 4 5 6 7 Give your diagram the title ‘River Basin’. Provide a date. Write neatly the numbers and corresponding definitions into your book.

Close your book!

Open your book! Badge off E-Bay!

A Quick Test Look at the next slide and write down what each of the number represent

21 3 4 5

48  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools Watershed and Drainage Basin

49  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools Where is the Watershed?

50  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

98  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools Drainage Basin 1

99  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools Drainage Basin 1

100  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools Drainage Basin 1 Drainage Basin 2

101  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools Drainage Basin 1 Drainage Basin 2

102  Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools Drainage Basin 1 Drainage Basin 2 Drainage Basin 3

A Pop Up River Basin

River Long Profile

Add these to the right place in the table Steep V Shaped Valley More suspended sediment Wide open valley Narrow Shallow Channel Open gentle sloping valley with floodplain High Bedload Flat and wide floodplain Wider Deeper Channel Very wide and very deep

A river changes shape as it flows from its source (where a river starts) to its mouth (where a river flows into a sea or lake). The shape of both the long profile (a slice through the river from source to mouth) and the cross profile (a slice across the river) changes.

Which picture would you find where?

River Severn – long profile journey : Answer these questions as we watch the BBC learning zone clip 340 What’s happening in the upper course? What’s happening in the middle course? What’s happening in the lower course? http://www.bbc.co.uk/learningzone/clips/the-course-of-the-river-severn-from-source-to-sea/340.html

Plenary Imagine an alien has landed in the classroom and wants to know what a river profile is. How would you answer him : tell your answer to the person sitting next to you

Recognise upper course features from maps and photographs To be able to explain how features such as V-shaped valleys and waterfalls are formed. To understand how the processes of erosion and weathering form these features. Upper Course of a River : Features and how they are formed Learning objectives:

Types of erosion Erosion and Transportation

The four main forms of river erosion Hydraulic action - the force of the river against the banks can cause air to be trapped in cracks and crevices. The pressure weakens the banks and gradually wears it away. Abrasion - rocks carried along by the river wear down the river bed and banks. Attrition - rocks being carried by the river smash together and break into smaller, smoother and rounder particles. Solution - soluble particles are dissolved into the river

Transportation

The four different river transport processes Solution - minerals are dissolved in the water and carried along in solution. Suspension - fine light material is carried along in the water. Saltation - small pebbles and stones are bounced along the river bed. Traction - large boulders and rocks are rolled along the river bed Rivers need energy to transport material, and levels of energy change as the river moves from source to mouth. When energy levels are very high, large rocks and boulders can be transported. Energy levels are usually higher near a river's source, when its course is steep and its valley narrow. Energy levels rise even higher in times of flood. When energy levels are low, only small particles can be transported (if any). Energy levels are lowest when velocity drops as a river enters a lake or sea (at the mouth).

write down answers to these questions on your upper course photograph How steep are the slopes? How wide is the channel? What is the bed load like? What are these? Where has most of the erosion happened here? How fast is the water moving?

Upper-course river features include: Steep-sided V-shaped valleys, Interlocking spurs, Rapids, Waterfalls Gorges. These are all features formed by EROSION!

Spurs…..

V-shaped valley

Rapids…….

Waterfalls….

Gorges….

Formation of Waterfalls and Gorges Using the above sequence to help you, write a short paragraph to explain how waterfalls form. Use the following words somewhere in your answer: Hard Rock Soft Rock Undercutting Plunge pool Erosion For National Five candidates you must also write about the type of erosions forces and how these help create the landform (waterfalls)

V-shape valley formation – write these out in the correct order in which a V-shape valley is formed This vertical erosion deepens the valley, making the sides steeper and exposed. As the small stream flows downhill steeply, the bedload will erode downwards and scrape away the bottom of the channel (vertical erosion) Over time, weathering and gravity wear away the steep valley sides, forcing material into the stream, which it uses to cut the valley deeper. A small stream will naturally follow small depressions in the landscape.

V-shape valley formation – CORRECT ORDER A small stream will naturally follow small depressions in the landscape. As the small stream flows downhill steeply, the bedload will erode downwards and scrape away the bottom of the chanel (vertical erosion) This vertical erosion deepens the valley, making the sides steeper and exposed. Over time, weathering and gravity wear away the steep valley sides, forcing material into the stream, which it uses to cut the valley deeper.

5,4,3,2,1, upper course Name 5 river upper course features Give the names of 4 types of river erosion Name the 3 courses of a river long profile Give 2 names of river features you can identify on a map Name 1 upper-course feature that you are confident in explaining to someone else.

Middle course, R. Tees Valley opens out, more gentle slopes, wider valley bottom First signs of meanders River channel wider, deeper, greater velocity and discharge WHAT DO YOU THINK THE ARROWS POINT TO?

Meandering Rivers WHAT IS A MEANDER?

Meander, R. Lavant, Chichester

Floodplain Point bar deposits on the inner meander bend where there is low energy River Cliff Slip-Off Slope WHAT DO THE ARROWS POINT TO? WHICH WAY IS THIS MEANDER MOVING?

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 bend where there is not enough energy to carry load. EROSION TYPE: Lateral Also known as the ‘Mature’ stage Meanders 1

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.

Cut bank erosion (River Cliff) Point bar deposits } Meander loop WHERE IS EROSION TAKING PLACE? WHERE IS DEPOSTION TAKING PLACE? A B C D E F

Meander on the R. Colorado WHY IS DEPOSITION OCCURING HERE?

How did these meanders form?

REVISION: What River features do you get here?

Migrating meanders, R. Gongola, Nigeria WHY ARE THEY MIGRATING?

What happens to the river when it moves to the middles course Gradient becomes less steep River continues to erode vertically but LATERAL erosion now occurs in MEANDERS What is MEANDER MIGRATION ? Name three effects it have on the valley? What factors effect how much load is being carried?

correct the mistakes The middle course of the river is narrower than the upper course. The middle course of the river has steep slopes to each side The middle course of the river has a narrow flood plain You find waterfalls in the middle course of the river

Lower Course: Severn Valley

Lower Severn Valley Well developed meanders with bars in the channel indicating high sediment load Very gentle valley side gradients HOW DOES IT DIFFER FROM THE MIDDLE COURSE? Very wide floodplain

Ox Bow Lake Formation LOOK AT THE DIAGRAM & EXPLAIN THERE FORMATION

Formation of an Oxbow

Flood Plains The entire floodplain can become covered with water during floods. HOW DO YOU THINK THE TERRACES WERE FORMED?

Ox Bow lake on Mississippi

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.

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.

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.

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.

Rivers and their Valleys. What you will need to do.. that there are different rock types on the Earth’s surface how weathering and mass movement occur.

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Rivers and their Valleys. What you will need to do.. that there are different rock types on the Earth’s surface how weathering and mass movement occur.

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Presentation on theme: "Rivers and their Valleys. What you will need to do.. that there are different rock types on the Earth’s surface how weathering and mass movement occur."— Presentation transcript:

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