In this article you will learn in a summarized way about the hydrological cycle, its stages or phases, which is also accompanied by an explanatory image to better understand the very important water cycle.
What is the hydrological cycle?
To summarize, the hydrologic cycle represents the continuous movement of water from oceans, rivers, lakes, and all water in the earth’s crust to the atmosphere, from the atmosphere to the land, and from the land to the sea.
In other words, it explains how water constantly circulates throughout the planet.
Stages or phases of the hydrological cycle
Water is constantly moving between the different spheres of the Earth: the hydrosphere, the atmosphere, the geosphere, and the biosphere.
This endless circulation of water, called hydrological cycle, describes what happens when water evaporates from the ocean, plants, and soil, moves through the atmosphere, and finally falls as precipitation.
The precipitation that falls on the ocean has completed its cycle and is ready to start another cycle.
When precipitation falls on land, it soaks into the ground, a process called infiltration, flows over the surface as runoff, or immediately evaporates.
Much of the water that infiltrates or escapes eventually returns to the atmosphere through evaporation from the ground, lakes, and streams.
Also, some of the water that penetrates the soil is absorbed by plants, which then release it into the atmosphere. This process is called transpiration.
Because both evaporation and transpiration involve the transfer of water from the surface directly to the atmosphere, they are often considered together as the combined process of evapotranspiration.
More water falls on land as precipitation than is lost through evapotranspiration.
The excess is transported to the ocean mainly by streams, less than 1 percent returning as groundwater.
However, much of the water that flows in rivers is not transmitted directly to the river channels after falling as precipitation.
Instead, a large percentage first penetrates the soil and then gradually flows as groundwater into river channels.
In this way, groundwater provides a form of storage that sustains streamflow between storms and during periods of drought.
When precipitation falls in very cold areas, at high elevations, or high latitudes, the water may not immediately soak, run off, or evaporate. Instead, it can become part of a snowfield or a glacier.
In this way, glaciers store large amounts of water. If today’s glaciers were to melt and release their stored water, sea levels would rise by several tens of meters around the world, submerging many highly populated coastal areas.
In the last 2 million years, huge sheets of ice have formed and melted several times, each time changing the balance of the planet. hydrological cycle.
The image of hydrological cycle it also shows that this cycle is balanced. Every year, solar energy evaporates about 320,000 cubic kilometers of water from the oceans, but only 284,000 cubic kilometers return to the oceans as precipitation.
The 36,000 cubic kilometers that are carried into the ocean as runoff strike a balance.
Although runoff constitutes a small percentage of the total, running water is nevertheless the most important erosive agent that sculpts the Earth’s land surface.
Processes: Volume of water that moves
hydrological cycle from the earth. The large arrows show the primary movement of water through the hydrological cycle.
Every year, solar energy evaporates about 320,000 cubic kilometers of water from the oceans, while evaporation from land (including lakes and streams) contributes 60,000 cubic kilometers of water.
Of this total of 380,000 cubic kilometers of water, about 284,000 cubic kilometers return to the ocean, and the remaining 96,000 cubic kilometers fall on the land surface.
Of those 96,000 cubic kilometers, only 60,000 cubic kilometers of water return to the atmosphere through evaporation and transpiration, leaving 36,000 cubic kilometers of water to erode the land during the return trip to the oceans.
Why does the hydrological cycle exist?
We live on a planet that is unique in the solar system: it is in the right location and the right size.
If the Earth were appreciably closer to the Sun, water would exist only as vapour.
Conversely, the water would freeze forever if our planet were much further away.
Also, the Earth is large enough to have a hot mantle that supports conductive flow, which brings water to the surface through volcanism.
The water that arose from the interior of the Earth through the convection of the mantle generated the oceans and the atmosphere of our planet.
Thus, by coincidence of favorable size and location, Earth is the only planet in the solar system with a global ocean and a hydrological cycle.
Water is found almost everywhere on Earth: in oceans, glaciers, rivers, lakes, air, land, and in living tissue.
All of these “water reservoirs” make up Earth’s hydrosphere, which contains about 1.36 billion cubic kilometers (326 million cubic miles) of water.
The vast majority, around 97 percent, is stored in the global ocean.
Ice sheets and glaciers make up just over 2 percent, leaving less than 1 percent to be split between lakes, streams, groundwater, and the atmosphere.
What is the importance of the hydrological cycle?
In the preservation of life
Water is one of the most important elements that living beings need to survive (animals, plants, microorganisms and human beings), and the hydrological cycle it allows water to be in constant movement and reaches all corners of our planet, thus allowing the proliferation of life.
Access to drinking water
Thanks to hydrological cycle, the water can reach the surface of the earth and especially to the places where the rivers and lakes are loaded with water again, this is important so that the big cities can be constantly supplied with drinking water.
In climate regulation
The water that goes to the atmosphere allows clouds to be generated and these clouds generate precipitation through rain, all this in turn is a fundamental part of climate regulation, pressure and temperature in the environment.
A more humid environment is generally warmer.