Water Cycle Diagram

What is a Water Cycle?

The water cycle, which is also known as the hydrological cycle can be described as the continuous circulation of water in the earth-atmosphere system. There are many processes involved in the water cycle, however, the most important phases are evaporation, transpiration and condensation, precipitation and runoff. The total amount of water within the cycle remains constant and the distribution process is continuously changing. The mass of water on the earth’s surface does remain the same throughout time, however, the partitioning of water into major reservoirs of ice, fresh, saline and atmospheric water changes, through the various processes of the water cycle. The cycle also involves the exchange of energy which results in the change of temperature. As water evaporates, it takes up energy from the environment which cools the area around the waterbody. Condensation of water releases energy and warms the environment. This article discusses the diagram of the water cycle and its explanation.

Water Cycle Diagram With Explanation

The water cycle is driven by solar energy. The sun heats the ocean surface and the surface of other water bodies which causes the liquid water to evaporate and ice to sublime turning it directly from solid to gas. In this section, we will explain the water cycle with the help of a diagram.

The Stages of Water Cycle Include the Following

• Precipitation:  Precipitation takes place via condensed water vapour that falls on the earth’s surface. Most precipitation takes place as rain but it only occurs via snow, hail, fog drip, sleet and graupel. 78% of global precipitation occurs over the ocean. 

• Canopy Interaction: This is intercepted by plant foliage and eventually evaporates back to the atmosphere and does not fall on the ground.

• Infiltration: In this phase, water flows from the ground surface into the ground. Once the water is infiltrated and the water becomes soil moisture or groundwater. 

• Subsurface Flow:  Subsurface water which is found in the underground, vadose zone and aquifers may return to the surface and eventually seep into the surface. Then, the water returns to the land surface at a lower elevation than where it infiltrates, under the force of gravity.

• Evaporation: This is one of the major phases of the processes of the water cycle. In this phase, water transfers from the surface back to the atmosphere. In evaporation, the liquid transforms into gas once some molecules in a water mass attain kinetic energy and eject themselves from the earth surface. The main factors that affect evaporation are temperature, humidity, solar radiation and wind energy. Evaporation from ice and snow is the direct conversion of water from solid to vapour phase and it is known as sublimation. Transpiration is the evaporation of water through pores in the leaves of plants.

• Condensation: In this phase of the water cycle, water vapour transforms into liquid water droplets in the air which creates clouds. 

• Runoff: As water runs over the ground, it displaces its top-most layer of soil. The displaced soil forms channels through which the water follows and feeds into the nearest streams and rivers. Because this water flows directly into rivers and streams it is sometimes referred to as streamflow. The runoff and streamflow steps of the water cycle play an important part in making sure water gets back into the oceans to keep the water cycle going

Below is a simple water cycle drawing will help you understand the different phases of the hydrologic cycle diagram and its explanation

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Hydrological cycle diagram

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Water cycle chart

Effects of the Water Cycle on Biogeochemical Cycles

Whilst the water cycle is also a biogeochemical cycle, the flow of water over and beneath the earth is a key part of the cycling of other biogeochemical cycles. The phase runoff is responsible for almost all of the transport of phosphorous and eroded sediment from land to various water bodies. 

The salinity of the oceans is derived from transport and erosion of dissolved salts from the land. Artificial eutrophication of lakes and many water bodies is primarily due to phosphorus, which is applied in excess to agricultural fields in the form of fertilizers. It is then transported overland and down rivers. 

Both runoff and groundwater flow play major roles in transporting nitrogen from the land to water bodies. The dead zone at the outlet of the Mississippi River is a consequence of nitrates from fertilizer transported from agricultural fields and funnelled down the river system to the Gulf of Mexico. Runoff also plays a role in the carbon cycle, through the transport of water in eroded rocks and soil.

The Global Distribution of Water

Have a look at the chart below to have a better idea of where the earth’s water exists.  At present, the total of the quantity of water on earth supplies about 332.5 million cubic miles of water and over 96% of that water is saline. The rest is freshwater out of which 68% is locked up in ice and glaciers and around 30% of the remaining freshwater is in the ground. Rivers and lakes, which are sources of surface-water, only constitute about 22,300 cubic miles, which is only 1/150th of one percent of total water. 

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