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Last updated date: 28th May 2024
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Define Hydrology

Hydrology is defined as the science that is concerned with all the aspects of water available on Earth. It deals with the study of the occurrence of water, its distribution, its properties, and circulation of water on Earth and other Planets including water resources, water cycle, and watershed sustainability.

A professional of hydrology is known as a hydrologist. Using different scientific techniques and analytical methods, hydrologists collect and analyze data to resolve water-related problems such as natural disasters, environmental preservation, and water management.

Hydrology Meaning

Understanding Hydrology's meaning is extremely important, as it is the science that deals with one of the most valuable resources on Earth known as Water. All aspects of the availability of water on Earth are studied by hydrologists to know the ways to manage this vital resource. Hydrologists rely on their understanding of how water interacts with its environment, including how it circulated from the Earth’s surface to the atmosphere, and then how it returns to Earth. This never-ending process of movement of water is known as the hydrologic cycle or the water cycle. 


The field of hydrology consists not only of studying the natural distribution and circulation of water, but it is also concerned with the impact of human activities on water quality and with problems in water management. Water is used by humans for different purposes. In homes, water is used for drinking, cooking, cleaning, and bathing. Many industries require large amounts of water. In agriculture, water is required for the irrigation of farmland and livestock. Water available in dams is used to produce hydroelectric power. The human uses of water are endless.

What is Hydrology?

Hydrology is the science that encompasses the study of water on Earth's surface and underneath the Earth surface, the occurrence and circulation of water, the physical and chemical properties of water, and its relationship with the human and material components of the environment. Eventually, the hydrology questions include the transfer of energy, nutrients, solutes, contaminates, or sediments as well as the water fluxes itself.

The hydrologic cycle or water cycle is the continuous process through which water gets purified by evaporation and transported from the Earth's surface (including the oceans) to the atmosphere and return to the land and the oceans. This happens through different concepts at different rates but the core concepts remain the same. 

Water vaporizes or evaporates from the ocean, liquidizes as clouds, moves over land, and precipitates. From there it can reach the groundwater, vaporize again, or enter a stream or lake. It will ultimately find its way to return to the ocean either by falling as precipitation, flowing with a river or by moving slowly with groundwater.  

The hydrologic cycle is also a process that transforms heat energy. Heat is transported towards the poles of the Earth by water being vaporized or evaporated and then condensing which releases heat. Without the water cycle, the climate would be much more frozen, and areas that are away from the equator would become inhabitable.

Hydrology Application

  • Hydrology helps to calculate the rainfall

  • Hydrology helps to calculate the surface runoff and precipitation

  • Designing bridges, sewers, irrigation schemes, and  urban drainage systems

  • Provides clean drinking water

  • Designing dams for hydroelectric power irrigation or water supply

  • Real-time flood warning and forecasting

  • Determining the water balance of a region and agricultural water balance.

  • Estimating or predicting the flood, landslide, or drought risk

  • Helping to analyze the impacts of antecedent moisture on the sanitary sewer system

  • Helps to predict geomorphology changes such as erosion or sedimentation

  • Managing agricultural productivity, and many more.

Did You Know?

  • Of all the availability of water on Earth, only 1% of it is suitable for human use.

  • Only 3% of the water available on Earth is freshwater available for drinking.

  • Precipitation can come about in the form of rain, sleet, snow, or hail.

  • When water evaporates into the atmosphere, it cools and condenses to form clouds through a process known as condensation.

  • When the clouds become too heavy from collecting water, it releases through a process known as precipitation.

  • 70% of the human brain is made up of water.

  • The Earth's hydrologic cycle began about 3.8 billion years ago when rain fell on Earth forming oceans 

FAQs on Hydrology

1. What are the 5 Processes for a Hydrological Cycle?

The 5 processes condensation, precipitation, infiltration, runoff, and evapotranspiration together make up the hydrology cycle. Water droplets condense to form clouds, which results in precipitation, where the conditions are favourable. Precipitation falls to the ground and either infiltrates the soil or flows to the oceans as runoff. Surface water such as lakes, streams, and oceans vaporizes, returning moisture to the atmosphere, while the plant returns water to the atmosphere through the process of transpiration.

2. What Do Hydrologists Do?

Hydrologists study various things including the water interaction with earth crust, how precipitation impacts the availability of groundwater and river levels and hence affects humans. The groundwater hydrologist focuses on the availability of water beneath the Earth's surface whereas the surface water hydrologist focuses on the groundwater sources. Hydrologists are also specialized in certain areas like groundwater remediation and the melting of glaciers.

3. Why are Hydrologic Cycles Important?

The hydrologic cycle is important because it enables the availability of water for all living organisms and regulates weather conditions on our planet. If water didn't recycle itself naturally, we would run out of water which is essential for human beings.