The Hydrological Cycle

This describes the process whereby water in its various forms is continually cycled between the land, sea and atmosphere. It also makes its way into the biosphere to influence animal and plant ecosystems around the globe.

A systems approach

This is a common approach in geography and the two main examples in this topic are:

The hydrological cycle: a closed system.

The drainage basin system: an open system.

Both consist of transfers, stores, inputs of water but the hydrological cycle is a closed system as no gains or losses from outside are added to the system.

The drainage basin system is said to be open as both inputs and outputs of energy and material occur. All systems in their natural state aim to be in a state of balance (dynamic equilibrium) as this is when they function best. Heavy rainfall, drought and human activity such as deforestation can easily upset the balance.

Within the hydrological cycle, four main processes operate:

1. Interception

This is when plants prevent some rainfall from directly reaching the ground, for example, water on leaves or foliage. It…