Water cycle

In this activity, we will face the need to optimize the use of water resources because of the impacts of climate change effects, we will learn about groundwater resources both in terms of human needs and environmental values.

We will begin with some background about the water cycle.

The global water cycle is crucial for life on Earth. The part of this cycle that is on land and above sea level (which is called the land water cycle) is fed by precipitation, meaning the sum of rainfall and snow fall. This sets the available volume of water.

The land water cycle can be subdivided into 3 components:

The first component is evapotranspiration. This includes both evaporation from water bodies and transpiration from plants. Evapotranspiration is mediated by plants. It is affected by temperature and varies according to time of day, season, altitude and latitude.

The second component is runoff. This is the flow of water across the land, down slopes and in valleys. Runoff is affected by rainfall intensity, slope angles and soil permeability. It is the fastest component of land water cycle.

The third component is infiltration, whereby surface water becomes groundwater which is contained within porous soils and rocks. Water flowing in soils moves slowly vertically downwards until it becomes groundwater beneath a surface which called the water table. Infiltration is affected by evapotranspiration, runoff as well as soil and rock permeability. These factors control recharge (refilling) of aquifers which, used wisely, can be viewed as a renewable resource of water fulfilling both human and environmental needs.

As we walk through the forest towards Kroka, listen to this podcast to find out more about groundwater: the hidden part of the water cycle.