lesson 4 river features
TRANSCRIPT
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