The Water Cycle means the circulation of water. There is a constant and continuous circulation of water from the Earth’s surface to the atmosphere and back to the Earth’s surface. The water cycle is an intricate combination of Evaporation and Condensation, transpiration, Precipitation, run-off, and groundwater movement.
Water on the Earth’s surface is able to evaporate thanks to the Sun’s heat (oceans, lakes, etc.). Additionally, plants lose water in the air (this is called transpiration). The term evapotranspiration denotes the combined process of evaporation and transpiration. Eventually, the water vapour condenses to create small droplets in clouds. When the clouds meet cool air over land, precipitation (rain, sleet, or snow) occurs, and water returns to the land (or sea). Some of the precipitation soaks into the ground.
Groundwater is the term for some subsurface water that is confined between layers of rock or clay. However, the majority of the water runs off in a downward direction (either above ground or subterranean), eventually returning as mildly salted water to the oceans.
Read More: Hydrosphere
What is Water Cycle?
The hydrological cycle is the movement of water through the hydrosphere of the Earth in its different phases, including liquid, solid, and gaseous. The Water Cycle is another name for it. It also describes the ongoing flow of water between the land surface, the oceans, the subsoil, and living things. This important occurrence is necessary for the hydrosphere to exist.
The water cycle, also known as the hydrologic cycle, is a continuous flow of water through the Earth-atmosphere system. Evaporation, transpiration, condensation, precipitation, and runoff are the five most important phases of the water cycle. All of the cycle’s operations require water, yet even while the total amount of water remains mostly constant, how it is distributed changes over time. Throughout the water cycle and in varied locations, water moves in a variety of ways.
The following reservoirs are claimed to hold water: the atmosphere, oceans, lakes, rivers, glaciers, soil, snowfields, and groundwater. Through evaporation and condensation, precipitation, runoff, infiltration, transpiration, and groundwater flow, water is transferred from one reservoir to another.
Read More: Climate of India
Water Cycle Stages
Evaporation, transpiration, condensation, precipitation, and runoff are the fundamental five phases of the water cycle.
Evaporation converts a substance from a liquid to a gas. In meteorology, water is the component that causes us the most concern. The energy is required for the evaporation process to take place. Energy can come from the sun, the planet, the atmosphere, or anything else on earth like people.
Evaporation is something everyone has personally experienced. When the body gets hot from the environment or from the effort, it sweats and secretes water onto the skin. The goal is to get the liquid to evaporate by using the body’s heat, which will remove heat from the body and allow it to chill. It has a similar effect to when you get out of the shower or the pool.
During transpiration, water from plants evaporates through stomata. On the underside of leaves, one can see stomata, tiny openings connected to vascular plant tissues.
The majority of plants’ passive transpiration is mostly controlled by the atmosphere’s humidity and the moisture content of the soil. A plant uses only 1% of the water lost through transpiration for its own growth. It is discharged into the atmosphere in 99.9% of cases.
Read More: Types of Clouds
The process through which atmospheric water vapour changes into a liquid state is called condensation. Clouds or dew are two examples of atmospheric condensation.
For condensation to happen, there must be a difference between the air temperature and the dewpoint temperature. In its most basic form, the dew point is the temperature at which dew can form.
If the air is cooled to that point, it is the temperature that makes the air saturated. Any additional cooling causes water vapour to condense. Foggy conditions typically arise when the dew point and air temperature are equal.
Evaporation’s opposite is condensation. Condensation releases extra energy in the form of heat energy because water vapour has a greater energy level than liquid water. Hurricane formation is aided by this heat release.
Tiny condensation particles produce precipitation when they become too big through collision and coalescence for the rising air to maintain. Rain, hail, sleet, or snow are all possible precipitation types.
The main source of fresh water on Earth is precipitation. The Earth receives about 38 1/2′′ (980 mm) of precipitation per year, both on land and in the oceans.
Runoff happens when there has been a lot of precipitation and the earth is saturated (cannot absorb any more water). Rivers and lakes are created by runoff. The majority of the water in rivers and lakes goes back into the oceans, despite some runoff evaporation taking place in the atmosphere.
If the lake is the only location where runoff water flows, evaporation is the only option for it to return to the atmosphere (there is no exit for the water to flow out of the lake). As water evaporates, salts or other pollutants are left behind. The lake subsequently turns salty, resembling the Dead Sea in Israel or the Great Salt Lake in Utah.
The hydrologic cycle is restarted as a result of this runoff evaporating into the atmosphere.
Read More: Structure of the Atmosphere
Water Cycle Diagram
Evaporation, transpiration, condensation, precipitation, and runoff are the fundamental five phases of the water cycle. Below is the illustration for the same.
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Water Cycle Significance
- The climate is significantly influenced by the water cycle. For instance, the greenhouse effect will cause a rise in temperature.
- If the evaporative cooling effect of the water cycle did not exist, Earth’s temperature would increase significantly.
- The water cycle has an impact on other biogeochemical cycles.
- Every living thing on Earth is impacted by the water cycle.
- The potential of the water cycle to filter the air is also well-known. For instance, in order to precipitate, water vapours must adhere to dust particles. In addition to dust, water-soluble gases and contaminants are absorbed by raindrops in smoggy cities.
- In addition to other things, it has been discovered that raindrops can pick up biological agents such as bacteria and remnants of industrial combustion.
Read More: Air Masses
Water Cycle UPSC
Water moves from the earth to the atmosphere and again back to the earth, completing the water cycle, which is a natural phenomenon. The water cycle involves a number of intricate processes, but it is responsible for replenishing our freshwater supplies, including rivers, lakes, and the groundwater table. The rain that the water cycle brings is also essential for plant growth, temperature regulation, and irrigation in agriculture. You will learn about the Water Cycle (Hydrologic) in this article, which will help you with the Geography and Environment syllabus preparation for the UPSC Civil Service Exam.