The importance of hydrological cycle on earth
Water is one of the world’s most valuable resources that has to be retained for an inclusive future. Water is absolutely important to life on earth. Water contributes to the major part of the earth and earth’s climatic balance.
The three states of water are:
Solid - Ice or snow, such as ice bergs and glaciers
Liquid - Water
Gas - Water vapor or steam
The Hydrological cycle explains the multi-step journey of water that transports from the surface of the earth, to the atmosphere and falls again to the earth’s surface.
The movement of water to and fro of the earth’s surface drives global weather pattern. There is an exchange of energy where water releases energy to warm the environment to condense and takes energy from the environment to evaporate, influencing climate change.
Hydrological cycle commonly known as water cycle illustrates the continuous movement of water on earth and above and below the surface of the earth. Throughout the course, water changes its state from one form to another by undergoing a variety of process such as:
- 1. Evaporation
- 2. Sublimation
- 3. Evapotranspiration
- 4. Condensation
- 5. Precipitation
- 6. Infiltration
- 7. Runoff
Water is found in various forms on the earth’s surface such as oceans, lakes, swamps, and soil, as well as in all living creatures and plants. Sun is the source of energy which drives the process of evaporation. Evaporation happens when heat is applied from sun the water molecules change its state of energy, it loses density and rise in the air in vapor form called evaporation. And thus, forming clouds.
Evaporation takes place when water reaches the boiling point. In areas were the humidity and air pressure are less, because the lower pressure cannot hold water molecules together, less heat energy is required for evaporation to occur.
There falls a doubt, if ice and snow could evaporate? Yes, Ice and snow can turn into water vapor directly without changing into liquid state. This happens when there is a low temperature, low air pressure, strong sunlight, strong wind, low humidity and dry winds. Less energy is needed to sublimate the ice into water vapor. Generally, this happens at the peak of the mountains such as Mount Everest. This is called sublimation.
Water evaporates from leaves of the plants and trees is called evapotranspiration. Hence the earth is covered by a large area of vegetation. Due to this process a huge amount of water is produced in the atmosphere.
Lakes, ocean, and streams contributes ninety percentage of water vapor, the plant life contributes to the remaining ten percentage.
The water vapor in the atmosphere cools down considerably. The water vapor comes in contact with the low temperature that is cooler air found up in the sky forming tiny droplets. Thus, forming clouds by the moving air currents and winds.
The water vapor condenses on tiny particles of dust, which rose while evaporation process. The water vapor attaches to the surface of the dust particles forming tiny droplets. The tiny droplets merge to produce a larger droplet in the clouds. This falls from the clouds to the ground surface as rainfall called precipitation.
The process of absorption of rain water into the soil to the ground is known as infiltration. Soil is a porous material that absorbs more water than rocks can hold. The rain water seeps into the soil to nearby streams or seeps deeper to ground water table forming aquifers.
While the snow melts or if rain does not reach aquifers, the water follows gravity and falls down to steeps or mountains and joins or forms rivers. This is called runoff . Water comes to lakes and return to ocean.
Importance of Hydrological Cycle Processes
List down are few reasons why the water cycle is important:
• Hydrological cycle plays a role in maintaining the balance of aquatic ecosystems. The water cycle is one of the major biogeochemical cycles of the earth, to maintain life on earth.
• The water cycle plays a major role to ensure availability of water to all the living organisms such as humans, animals, plants and other living species.
• The hydrologic cycle is the natural process that plays a important role in the continuous transformation of water above and below and on the surface of the Earth. Also recycles minerals, nutrients, pathogens, and elements along with the water in the ecosystem.
• Human life is totally dependent upon the fresh water. Water makes 70 percent of all living organisms, and humans rely on water. The water cycle is an extremely essential process that enables the availability of water for all living organisms and regulates global weather patterns.
• A natural depot of freshwater sources for both humans and other organisms are: Glaciers, ice, and snow. There is a need for the aquatic life, to maintained pH levels of salt water and saline ranges to sustain in the sea or ocean. So, water has to be purified even for aquatic ecosystem and for the benefit of human life, animal life and plant life.
• According to researchers, only three percent of water is freshwater accounts for all the water on Earth. On the wholesome of these three percentages, the majority two percentage of water is in the form of glaciers and ice bergs or stored below ground. The remaining one percent is to be found in rivers, wetlands and lakes or in the form of water vapor, clouds and precipitation.
• Just imagine if the water cycle doesn’t take place, i.e. recycling of water does not happen to distribute freshwater all over the surface of the earth, we human and other living species would run out of clean water, which is essential to live.
• Effects of hydrological cycle on climate. Eighty-six percentage of the evaporation in the global level occurs from the oceans. Sun is the major power source that drives water cycle. Without the cooling effect temperature on earth would rise drastically
• The greenhouse effect would lead to a rise in surface temperature of sixty seven degree Celsius (one fifty three degree Fahrenheit) and a warmer earth.
• Evaporation and infiltration help purification of water by natural process, when evaporation takes place the dust or the sediments are left behind. Whereas while the water undergoes infiltration, when the water seeps into the soil, soil is a porous material which can naturally filter contaminants and pollutants from the water.
• The water cycle process supports life and creates a biological community of interacting organisms and their physical environment around us. Some organisms are sensitive to changes that take place in the water cycle. An extended drought can end the existence of a population of plants or a certain species may require a point of saturated soil in order to avoid the removal of moisture content for them.
• The water cycle operates and controls Biogeochemical Cycle. The water cycle and rainfall pattern influences Earth’s ecosystems. Rainfall and surface runoff plays major role in the cycling of various elements.
• Surface runoff helps in the movement of elements from terrestrial, land-based, to aquatic ecosystems. In ecology and Earth science, a biogeochemical cycle is cycling of substances is a pathway by which chemical substance also moves through biosphere, lithosphere, atmosphere, and hydrosphere of Earth. This includes chemical elements such as carbon, oxygen, hydrogen, nitrogen, mercury, phosphorus, calcium, selenium, and sulphur etc.
• Rainwater plays a key role in climatic changes. Rainwater harvesting is a process done to collect rainwater and store it for human use. Global problem needs a speedy solution. One such methos is rain water harvesting, which would be a great solution during water scarcity.