Transfers in the hydrological cycle revision notes

Edexcel International GCSE Geography (4GE1), chapter 1: River environments, specification point 1.1a. Free lesson.

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A transfer is the movement of water from one store to another in the hydrological cycle. Knowing the route water takes, and how each transfer works, helps you explain how it moves from the sea to the land and back again.

How water moves through the air

Water rises from the sea, forms clouds and then falls back to land. Evaporation and transpiration move water into the air. As the water vapour cools, condensation forms cloud droplets, and precipitation returns water to the surface. Evaporation: heat from the sun turns liquid water at the surface into water vapour, which rises. Transpiration: plants take up water through their roots and lose it as vapour from their leaves. Evaporation and transpiration together are called evapotranspiration. Condensation: water vapour cools and turns into tiny liquid droplets,…

What happens when water reaches land

On a hillside, water can be caught by vegetation, travel over the surface or soak into the ground. These routes differ in where the water goes and how quickly it moves. Interception happens when leaves and branches catch rain. The water held there is part of the vegetation store, so interception is not the name for water moving between stores. Surface runoff, also called overland flow, is water flowing over the ground into a river. It is the fastest route. Infiltration is water moving down from the surface into the soil.

How water moves below ground

The four transfers below ground are easier to tell apart by the material they move through and their direction. Water moves faster through soil than through rock, so groundwater flow is the slowest of these transfers. Moving down into the soil is infiltration. Moving down from the soil into the rock is percolation. Moving sideways through the soil towards a river is throughflow. Moving through the rock towards a river or the sea is groundwater flow. Rivers and groundwater return water to the sea, where the cycle can begin again.

Stores are not the same as transfers

A store holds water in one place. A transfer describes water moving between places. This distinction helps you choose the right term in an answer. Groundwater is water held in rock, so it is a store. Groundwater flow is the transfer of that water through the rock. Soil moisture is a store. Throughflow is the transfer of water sideways through the soil.

How to earn marks when explaining a transfer

For a two-mark explanation, give the transfer's name and then explain how it moves water. Naming the process alone may earn only one mark. For water moving from the sea to the air, name evaporation and explain that the sun's heat turns liquid water into water vapour, which rises. For water moving from the atmosphere to the land, name precipitation and explain that droplets grow too heavy to stay in the air, so gravity pulls them down as rain, snow or hail.