Access GeographyWeek 17

Upper, middle or lower

Erosion, transportation and deposition are driven by the rivers energy.

Erosion occurs where the river has the most energy.

Deposition occurs where the river loses energy, where it

flows slowly.

Looking at these processes in action…

EROSION TRANSPORTATION DEPOSITION

Erosion: Rivers pick up material or erode material from one place…

Transportation: Then the river carries, or transports it to another place…

Deposition: Then, when the river slows down and loses energy it drops or deposits its load.

The Upper Course

The Middle Course

The Lower Course

Use these words to annotate/label your sketches:

Steep Valley Sides

Shallow

Deep

Wide

Narrow

Surrounding Land Flat

Turbulent/Choppy River Flow

Smooth River Flow

Rocky

Sketching the River at different points in its course

Rapids

Rapids on the Rhone

The Wonder of Waterfalls

Iguazu Falls, Argentina

Angel Fall, Venezuela

Mind Blowing Meanders

Waterfall Formation

How do waterfalls form?

Task: 1)Stick in your diagram of the waterfall.2)Put the labels in the correct position on the diagram to explain how waterfalls form.

Extension: 1) Write a paragraph to explain how a waterfall is formed on a river.

2) Explain how a gorge is formed in the river.

What are these words connected to waterfalls?

• Dharckor• Englup Lopo• Tofsckro• Deero• Druneuct• Orgeg

Meander = a bend in a river

Oxbow Lakes

Floodplains and levees are formed by deposition in times of river flood. The river’s load is composed of different sized particles. When a river floods it deposits the heaviest of these particles first. The larger particles, often pebble-sized, form the LEVEES. The sands, silts and clays are similarly sorted with the sands being deposited next, then the silts and finally the lightest clays. This deposition makes up the FLOODPLAIN.

Floodplain Formation

Floodplain of the Rhone

Old floodplain of the Rhone …

The large pebbles absorb the heat of the sun.How do you think the pebbles got to be here?

Orchard

Delta Formation

Delta are found at the mouth of a river, where the river meets the sea. At this point the river is carrying too much load for its velocity and so deposition occurs. The top of the delta is a fairly flat surface. This is where the coarsest river load is dropped. The finer particles are carried into deeper water. The silt is dropped to form a steep slope on the edge of the delta while the clay stays in suspension until it reaches the deeper water.

Annotate the delta with the following label:

silt clay

sand

This is a cross section of a floodplain. Draw a simple sketch of the diagram and annotate with the following labels

LeveesClays and silts

Sands

The River Conwy has deposited material in this section of its course. Suggest reasons why this has happened.

This is a cross section of a meander bend. Sketch the diagram and mark on the following

Slip off slopeRiver Cliff

Area of depositionUndercutting

Fastest velocity

Which of the following landforms are primarily caused by: * processes of erosion? * processes of deposition? * a mixture of erosion and deposition?

Draw out the table and insert the following landforms into the correct column. Indicate whether they are predominately found in the Upper or Lower Course by inserting a ‘U’ or ‘L’ after each feature.

DeltasMeanders Floodplains

Waterfalls LeveesOxbow lakes

RapidsV-shaped valleys Interlocking spurs

Erosion Deposition Erosion & Deposition

Give evidence to show that this is the lower course of the river. Use grid references where possible.

48 49 50 51

61

62

63

64

4760

Reproduced from the Ordnance Survey 1:50 000 Landranger raster data with the permission of HM Stationary Office © Crown copyright

What do you expect to happen to the following variables as you travel downstream?

• Discharge• Channel width• Water depth• Velocity• Load quantity• Load particle size• Channel bed roughness• Gradient

The Bradshaw model

The Schumm Model

The Hjulstrom curve