Throughfall is water that drips from a canopy or falls through gaps in it to reach the ground.

Stemflow is intercepted water that runs down the trunk or stem of a plant to reach the ground.

Infiltration is the movement of water from the ground surface into the soil.

What is infiltration capacity?

Infiltration capacity is the maximum rate at which a soil can absorb water, usually given in millimetres per hour.

Give two conditions that lower the infiltration capacity of a soil.

Compaction by machinery or livestock, and a soil already saturated by earlier rainfall.

Explain how infiltration-excess overland flow is generated.

Rain falls faster than the soil can absorb it, so the surplus cannot enter the soil and runs across the surface even though the soil is not full.

WJEC A-Level Geography 601-8455-3

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Water and Carbon Cycles

Flows within the drainage basin

3 things to know
A2 Unit 3

Overview

Infiltration capacity, how infiltration-excess overland flow is generated and how saturation-excess overland flow is generated.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Define throughfall.

Key term

What is stemflow?

Key term

Define infiltration.

Questions from this subtopic

Each one with the model answer underneath.

1
Define throughfall.
Model answer
Throughfall is water that drips from a canopy or falls through gaps in it to reach the ground.
2
What is stemflow?
Model answer
Stemflow is intercepted water that runs down the trunk or stem of a plant to reach the ground.
3
Define infiltration.
Model answer
Infiltration is the movement of water from the ground surface into the soil.
4
What is infiltration capacity?
Model answer
Infiltration capacity is the maximum rate at which a soil can absorb water, usually given in millimetres per hour.
5
Give two conditions that lower the infiltration capacity of a soil.
Model answer
Compaction by machinery or livestock, and a soil already saturated by earlier rainfall.
6
Explain how infiltration-excess overland flow is generated.
Model answer
Rain falls faster than the soil can absorb it, so the surplus cannot enter the soil and runs across the surface even though the soil is not full.

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