River Processes Today we are learning to Understand

River Processes Today we are learning to: • Understand how rivers form. • Describe the different processes of erosion and transportation.

River Long Profile River Structure fast

RIVER PROCESSES: - EROSION ATTRITION ABRASION Material moved along the river bed bumps collides and breaks up into smaller pieces. Fine material rubbing against the river bank and wearing it away. Erosion means the wearing away of the land. Most erosion occurs when the river is in flood. There is lateral (sideways) and vertical (downwards) erosion CORROSION HYDRAULIC ACTION The banks and bed of the river are dissolved by acids in the water. The force of the water hitting the banks of the river wears them away and causes them to collapse.

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Definitions Hydraulic Action This process involves the force of water against the bed and banks. Abrasion This is the process by which the bed and banks are worn down by the river’s load. The river throws these particles against the bed and banks, sometimes at high velocity. Attrition Material (the load) carried by the river bump into each other and so are smoothed and broken down into smaller particles. Corrosion This is the chemical action of river water. The acids in the water slowly dissolve the bed and the banks.

Lesson aim: Understand the different processes active in a river channel.

Lesson aim: Understand the different processes active in a river channel.

Lesson aim: Understand the different processes active in a river channel.

Lesson aim: Understand the different processes active in a river channel.

Lesson aim: Understand the different processes active in a river channel.

Do you know your processes of erosion?

RIVER PROCESSES: TRANSPORTATION This is the movement of eroded material. Eroded material includes particles of clay, sand, pebbles and boulders. Traction: large rocks and boulders rolled along the river bed Saltation: smaller stones are bounced along the bed of the river in a leap frog movement. Suspension: fine material is light enough to be carried by the river. This material may discolour the water. River flow ………. . . …. …. . Solution: some minerals dissolve in the water. These are always in the river.

River transport processes – can you see them. .

Transportation • Four animations to focus the mind, which is which? Or in other words …transortation

Traction

Saltation

Suspension

Solution

CC- Aerial Photography

Erosion is the mechanical wearing away of rock. Box style

Transport is the movement of eroded material by the river. Knees up march…

Material may float in a river- called floatation. Wavy arms…

Saltation is when material is bounced along the riverbed. Clenched fist

Material may be dragged across the riverbed. Pull it down

Suspension is when material is held by the water. Warm hug

Solution is when material is dissolved in the water. Jazz hands

Deposition is when the river drops material it has carried. Please be seated…

Timed…

Illustrate the different processes in cartoon fashion. Transport Flotation Saltation Dragged Suspension Dissolved Deposition Erosion