• What is the water cycle?
• Characteristics of the water cycle
• Stages and processes of the water cycle
• Importance of the water cycle
• Alterations of the water cycle

We explain what the water cycle is and its stages: evaporation, condensation, precipitation, infiltration, runoff, melting and more. In addition, its characteristics and importance.

The water cycle is vital for the maintenance and stability of planet Earth.

What is the water cycle?

The water cycle or hydrological cycle is the process of water circulation in the planet Earth. It constitutes one of the most important biogeochemical cycles, in which the Water suffers displacements and physical transformations (due to the action of factors such as cold and heat) and goes through the three states of matter: liquid, solid and gaseous.

This cycle is made up of stages and processes in which the water changes its state in a cycle that repeats itself continuously and without limits. Water is a fundamental substance for the life on Earth (all living beings need water to live and develop) and their cycle is what allows them to circulate through the hydrosphere and be available.

Water is one of the most abundant substances on the planet and covers most of the Earth. It can be found in its liquid phase in oceans or seas, in its solid phase in glaciers and in its gaseous phase in the water steam.

How is water distributed on planet Earth?

• In liquid state. 71% of the earth's surface is covered by liquid water, of which 97% is salty water that forms the oceans.
• In solid state. A fraction of the water on Earth is in a solid state, that is, accumulated as ice. Glaciers and polar caps, located mainly in Greenland and in the Antarctica, occupy 10% of the planet's surface and represent 69% of the fresh water available.
• In a gaseous state. A minor fraction of water is in the gaseous state, as water vapor, and is part of the atmosphere.

Characteristics of the water cycle

The melting of ice is an example of melting.

Some of the characteristics of the water cycle are:

• It is a hydrological cycle in which water circulates on planet Earth in different states: liquid, solid and gaseous.
• It is made up of four main stages: evaporation, condensation, precipitation and collection.
• Various environmental factors intervene in it, such as wind and solar energy (which is the main driver of this cycle).
• It does not have its beginning at a certain point, but rather it is a continuity of processes that are successively repeated. However, for its study the phenomenon of evaporation is used as the beginning of this cycle.
• It is vital for the maintenance and stability of the planet because it is essential for the life of organisms and, in addition, it regulates the weather, the temperature world and other conditions on Earth.

Stages and processes of the water cycle

The water cycle is made up of different processes.

The water cycle is made up of four main stages that occur in succession:

• Evaporation. The water cycle begins with the evaporation of water from the surface into the atmosphere. Liquid water in the oceans and other bodies of water evaporates from a liquid to a gaseous state, due to the action of sunlight and the global warming. Living beings also contribute to the evaporation process, through perspiration (in the case of plants) and sweating (in the case of animals).
• Condensation. Then, the water in the atmosphere moves, by action of the wind, in different directions. When water vapor reaches higher altitudes, low temperatures allow it to condense, that is, to regain its liquid form and form water droplets that accumulate in clouds. Clouds become dark as they contain more water droplets.
• Precipitation. When the water droplets contained in the clouds are large and heavy, they break their state of equilibrium and rain or precipitation occurs. Generally, water falls in a liquid form, but in certain regions where temperatures are lower, it can fall in a more or less solid form, such as snow, frost or hail.
• Harvest. Of the water that reaches the earth's surface, one part feeds the oceans and other bodies of water and another is directly used by living beings. A third fraction of the water that precipitates is filtered through the I usually and accumulates forming aquifers or layers of groundwater. This water, eventually, can re-emerge in the form of sources or as part of different bodies of water (such as streams or rivers) or return to the ocean through underground flow. Sooner or later, the water evaporates again and the cycle begins again. Within this step there are processes such as:
  • Infiltration. The water that reaches the terrestrial soil penetrates and becomes underground water. The amount of water that filters through the surface depends on different factors such as the permeability of the soil, the slope and the vegetation cover of the region. The infiltrated water can then return to the atmosphere by evaporation or be incorporated into different bodies of surface water.
  • Runoff Liquid water falls on saturated land (which cannot absorb more water) and moves across the surface to the river network. Runoff generates erosions and carries sediment. A given area of ​​land drained by runoff is called a watershed.
  • Underground circulation. Water that seeps through pores in the earth then travels underground, sometimes even through permeable rocks. The porous layers of rock in which groundwater is stored are called aquifers.

In addition, water is part of other processes such as:

• Fusion. It is the transformation of water from its solid state (ice or snow) to liquid, when thawing occurs. Thus, the melting of ice, as occurs at the poles and in frozen continental regions, returns the water to its initial point in the cycle.
• Solidification. It consists of the passage of water from the liquid to the solid state and occurs when the temperature is less than 0 ºC. The solidification process can take place in clouds, leading to the formation of snow or hail, and also on the surfaces of lakes and rivers, when temperatures are low enough.

Importance of the water cycle

Water is the substance that allows life on planet Earth and it is thanks to its cycle that the amount of available water is kept constantly and in continuous circulation. Through this cycle, the water is filtered and acquires its initial purity.

The water cycle is a vital process because, first of all, it allows life to exist on the planet and, in addition, it allows to conserve the ecosystems as they are known today. The constant movement of water is responsible for regulating climates, temperature and humidity of a site, the erosion of the land and transporting substances from one place to another.

Thanks to this cycle, water is available to be used by living beings, who obtain it from water courses or from the land. In addition, it allows the human being to carry out activities such as farming and industrial processes.

Of the total water in the world, only 3% is fresh water (which is what can be consumed by living beings) and the rest is salt water that comes from the oceans, so take care of the available water and not alter its cycle allows life on the planet to be housed and the balance of ecosystems to be maintained.

Alterations of the water cycle

The water cycle is a natural cycle that remains constant, which means that it always has the same amount of water that is being transformed and displaced. However, there are both human and nature that can affect the correct operation of this cycle.

Among the most prominent causes is global warming, which is the increase in temperatures on Earth, which produces phenomena such as increased water temperatures, increased rainfall, melting of glaciers and rising levels. of the oceans. All these consequences that rise in temperatures brings directly affect the correct functioning of the water cycle.

There are other causes that affect the development of the cycle, among which are: the indiscriminate felling of woods, soil erosion, water extraction, urbanization, among other. These practices alter the normal hydrological cycle and bring consequences such as floods and droughts.

Since a very small percentage of the available water is suitable for human consumption, its scarcity and the difficulty of obtaining high-quality water are two factors to consider. For this, practices are promoted that aim to reduce its consumption, avoid its contamination and manage this resource in a responsible way so that it can be available to the world population.