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Water Availability: A Detailed Summary


Last updated date: 18th Mar 2023
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For the luck of we human beings, earth is a watery place. On earth, water exists in different forms like oceans, rivers, water vapours in the air, icecaps, glaciers, aquifers, and soil moisture. These are all the water resources of Earth. Approximately 71% of the earth’s surface is covered with water, and 97% of all Earth's water is held by the ocean. Only 3% is held in by rivers, lakes, underground water, etc.

Due to the water cycle, Earth’s water supply is constantly moving from one place to another place and from one form to another form. In this article, we are discussing the availability of water on Earth and the availability of water resources

Water Availability

The meaning of availability is the quantity of something that can be used. Water availability is the quantity of water that can be useful to human beings without causing any harm to the ecosystem or other living creatures. According to the statistics, almost 97% of the earth's water is saline, and among the available 3%, aquifers are considered economically useful water resources for human beings.

Water availability, both surface water and groundwater, is crucial for various fields like agriculture, industry, energy generation and most importantly, human consumption. Climate, local geological conditions, use of land, quality of water everything will affect the water availability.

Availability of Water on Earth

Approximately 71% of the earth’s surface is covered by water. Water on earth can be divided into underground water and surface water. Surface water includes water from the ocean, lakes, rivers, icetops, and glaciers. Among these freshwater resources are water falling from the sky, lake, rivers, streams and underground water.

Underground water is the water below our feet that is more important to live. Surface water is mainly used for agricultural needs and as drinking water, whereas groundwater helps to keep rivers and lakes full. More than 8,400,000Km3 of freshwater is available on earth. Most of it is stored in ice caps and glaciers in the polar regions.

The water cycle has a crucial role in the availability of water on earth. Due to the water cycle, water on the earth moves from one place to another, and because of it, water reaches animals and plants. The water cycle is driven by solar energy. Deforestation, climate changes, the channeling and diverting of waterways, etc. can influence the water cycle and thereby the availability of water on earth.

Water Resources

The meaning of water resources is the natural resources of water that can be useful to human beings. We are using water resources mainly as a source of drinking water and for agricultural purposes, household activities, environmental activities, and industrial purposes. Among the available water resources oceans are contributing 97% to the water availability. Underground water, surface water like rivers and lakes, and frozen water are the natural sources of freshwater.

Desalinated water and water obtained after wastewater treatments can be considered artificial water resources. Water pollution, climate change, scarcity of water and various human activities badly affect water resources.

Availability of Water Resources

Natural water resources can be broadly classified as surface water, underground water and frozen water. Surface water resources are oceans, lakes and rivers. Aquifers are economically useful groundwater. Water from ice caps and glaciers belongs to the category of frozen water resources.

  • Saltwater: About 97% of the earth's water is held by oceans. The sea water is salty because of the presence of chloride and sodium ions on a large scale. Along with that, elements like calcium magnesium, potassium, etc., are also found in seawater. Saltwater cannot be drunk directly or cannot be used for irrigation. To use salt water for human needs, it should undergo a desalination process. For people living in dry places, the desalination process provides much more fresh water.

  • Ice- 2.06%: Most of the freshwater on earth is stored in the form of ice. In the north and south poles, ice is found as ice caps, and in the mountains, it is found in the form of glaciers. Approximately 90% of the earth’s ice can be seen in Antarctica.

  • Groundwater- 0.9%: Groundwater has been seen in every place on the earth below our feet. During rain, rainwater is filtered through the soil and reaches the area where it is already saturated with water. Depending on the depth of these areas groundwater can be days to thousands of years old. Aquifers are the places where groundwater collects in water wells and are the most economical water resources for human beings.

  • Lakes- 0.008%: Lakes are formed either by the accumulation of snow or by the seeping out of groundwater to the surface of the earth. Lakes can contain both freshwater and salty water. Freshwater lakes are highly important for people.

  • Wetlands- 0.0001%: Wetlands are formed in areas where water covers the soil for a long period of time. Deltas, estuaries, marshes and swamps are wetlands. wetlands are places where both land-dwelling and aquatic animals can coexist.

Interesting Facts

  • The depth of Earth’s oldest lake Lake Baikal in Siberia, is 1,500 m

  • If all the ice on earth melted at once, the sea level would increase by 20 feet.

  • The Great Artesian Basin In Australia is the largest aquifer in the world.

Key Features

  • Water availability is the amount of water available for human purposes without harming the ecosystem.

  • The natural resources of water are called water resources.

  • Water resources can be classified into surface water, groundwater and frozen water.

  • Only 3% of water is freshwater, and 97% of the water on earth is salty.

FAQs on Water Availability: A Detailed Summary

1. What are the factors affecting water availability?

There are a lot of factors that can affect the availability of water on earth like climate, geology, pollution, poor infrastructure and poverty. Once the water cycle on earth is threatened, it can seriously affect water availability. Deforestation, channelling, etc. are human activities that can challenge water availability. 

2. What are the freshwater water resources?

Water resources like rivers, lakes, groundwater, and icecaps are freshwater water resources. Among this, almost 90% of freshwater is held in the form of ice caps and glaciers in the poles and in mountains. If the ice on the earth started melting, it would enhance the sea level. Groundwater aquifers are economically viable freshwater resources. Wetlands can also contribute to the freshwater amount on earth.

3. How can the freshwater availability be improved on earth?

Freshwater availability can be improved on earth by taking up measures like reducing land and water pollution which are the major factors that degrade the quality of groundwater. Setting up technologies like rain water harvesting that enhance the percolation of water into the ground,etc.