L.O: Investigate river variables that change from source to mouth.

All MUST identify which variables increase and decrease (D).

Most SHOULD explain the processes that affect these variables (C-B).

Some COULD identify key river landforms (A-A*).

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Rearrange the words below to define different river variables…

1. LCOETIYV 2. SICDREGHA3. OALD (ZEIS)

4. ROCSS

EOCNIATLS

REAA

5. RCTINIFO

6. ARDGEITN 7. AHNCENLGHOUSSREN

Answers: 1. Velocity; 2. Discharge, 3. Load (size), 4. Cross Sectional Area, 5. Friction, 6. Gradient, 7. Channel Roughness

Starter:

Remember that using key vocabulary such as this is essential (AF7 – Effective Vocabulary)

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River characteristics vary as rivers move from source to mouth. Bradshaw was a river engineer who devised a model that can be applied to rivers. He stated that as a river moves downstream, some variables increase whilst others decrease.

This side of the model shows the

variables that are

greatest/largest at the source

of the river (the upper

course).

This side of the model shows the

variables that are

greatest/largest at the mouth

of the river (the lower course).

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Width x depth – a calculation of the

total area of the river channel.

The size of material

and sediment carried

in the water.

The angle or slope of

the river channel and

surrounding area.

The volume of water in the river channel.

The quantity of sediment carried within the body of

water.

The ability of the river channel to move water and sediment.

The amount of

churned or fast

pockets of water

(eddies) within a

river channel.

The speed at which the water flows within the river channel.

The smoothness of the river channel.

The resistance that builds between the

water and river channel.

@ Teachable and Ruth Edgar. Some rights reserved. http://teachable.net/res.asp?r=9464

River Variables Definition Change from source to mouth

(increase/decrease)

Explanation

Cross Sectional Area

Width x depth – a calculation of the total area of the river

channel.

Load (size) The size of material and sediment carried in the

water.

Gradient The angle or slope of the river channel and surrounding area.

Discharge The volume of water in the river channel.

Load (amount) The quantity of sediment carried within the body of

water.

Efficiency The ability of the river channel to move water and

sediment.

Turbulence The amount of churned or fast pockets of water (eddies) within a river

channel.

Velocity The speed at which the water flows within the river

channel.

Channel Roughness

The smoothness of the river channel.

Friction The resistance that builds between the water and river

channel.

@ Teachable and Ruth Edgar. Some rights reserved. http://teachable.net/res.asp?r=9464

UPPER COURSE LOWER COURSE

On your copy of these two photographs, add annotations to show how the variables change from source to mouth:D-C = Label three key variables you can identify on each photograph.B = Describe how three key variables change between the two photographs.A-A* = Explain how three key variables change between the two photographs and how that has affected the size and shape of the river channel.@ Teachable and Ruth Edgar. Some rights reserved. http://teachable.net/res.asp?r=9464

L.O: Investigate river variables that change from source to mouth.

All MUST identify which variables increase and decrease (D).

Most SHOULD explain the processes that affect these variables (C-B).

Some COULD identify key river landforms (A-A*).

@ Teachable and Ruth Edgar. Some rights reserved. http://teachable.net/res.asp?r=9464