HYDROLOGY: HISTORY, OBJECT OF STUDY AND RESEARCH - SCIENCE - 2025

The hydrology is the science that deals with the study of water in all its aspects, including its distribution on the planet and its hydrological cycle. It also addresses the relationship of water with the environment and living beings.

The first references to the study of the behavior of water date back to Ancient Greece and the Roman Empire. The measurements of the flow of the Seine (Paris) made by Pierre Perrault and Edme Mariotte (1640) are considered the beginning of scientific hydrology.

Hydrometeorological station in the Serra da Bocaina National Park, Brazil. Source: Halley Pacheco de Oliveira, from Wikimedia Commons.

Subsequently, field measurements continued and increasingly accurate measuring instruments were developed. Hydrology currently bases its research mainly on the application of simulation models.

Among the most recent studies, the evaluation of the retreat of glaciers due to global warming stands out. In Chile, the glacial surface of the Maipo basin has retreated by 25%. In the case of Andean glaciers, their reduction is related to the warming of the Pacific Ocean.

History

Ancient civilizations

Due to the importance of water for life, the study of its behavior has been the object of observation since the beginning of humanity.

The hydrological cycle was analyzed by different Greek philosophers such as Plato, Aristotle and Homer. While in Rome Seneca and Pliny were concerned to understand the behavior of water.

However, the hypotheses put forward by these ancient sages are considered wrong today. The Roman Marco Vitruvius was the first to indicate that the water infiltrated into the ground came from rain and snow.

In addition, at this time a large amount of practical hydraulic knowledge was developed, which allowed the construction of large works such as the aqueducts in Rome or the irrigation canals in China, among others.

Renaissance

During the Renaissance, authors such as Leonardo da Vinci and Bernard Palissy made important contributions to hydrology; They were able to study the hydrological cycle in relation to the infiltration of rainwater and its return through the springs.

XVII century

It is considered that in this period hydrology as a science was born. Field measurements were started, particularly those carried out by Pierre Perrault and Edmé Mariotte in the Seine River (France).

Edmond Halley. Source: Unknown, via Wikimedia Commons

The work done by Edmond Halley in the Mediterranean Sea also stands out. The author succeeded in establishing the relationship between evaporation, precipitation and flow.

Century XVIII

Hydrology made important advances in this century. Numerous experiments were carried out that made it possible to establish some hydrological principles.

We can highlight Bernoulli's theorem, which states that in a stream of water the pressure increases when the speed decreases. Other researchers made relevant contributions in relation to the physical properties of water.

All these experiments constitute the theoretical basis for the development of quantitative hydrological studies.

XIX century

Hydrology grows stronger as an experimental science. Important advances were made in the field of geological hydrology and in the measurement of surface waters.

During this period, important formulas applied to hydrological studies were developed. The Hagen-Pouiseuille equation of capillary flow and the Dupuit-Thiem well formula (1860) stand out.

Hydrometry (discipline that measures the flow, force and speed of moving liquids) lays its foundations. Formulas for flow measurement were developed and various field measurement instruments were designed.

On the other hand, Miller, in 1849, found that there is a direct relationship between the amount of precipitation and the altitude.

20th and 21st centuries

During the first part of the 20th century, quantitative hydrology remained an empirical discipline. In the middle of the century, theoretical models began to be developed to make more accurate estimates.

In 1922 the International Association for Scientific Hydrology (IAHS) was created. The IAHS groups hydrologists worldwide to the present day.

Important contributions are made in well hydraulics and water infiltration theories. Likewise, statistics are being used in hydrological studies.

In 1944, Bernard laid the foundations for hydrometeorology by highlighting the role of meteorological phenomena in the water cycle.

Currently, hydrologists in their different fields of study have been developing complex mathematical models. Through the proposed simulations, it is possible to predict the behavior of water under different conditions.

These simulation models are very useful in the planning of large hydraulic works. Furthermore, it is possible to make more efficient and rational use of the planet's water resources.

Field of study

The term hydrology comes from the Greek hydros (water) and logo (science), which means the science of water. Therefore, hydrology is the science that is responsible for the study of water, including its patterns of circulation and distribution on the planet.

Water is an essential element for the development of life on the planet. 70% of the Earth is covered with water, of which 97% is salty and makes up the world's oceans. The remaining 3% is fresh water, and most of it is frozen at the world's poles and glaciers, making it a scarce resource.

Within the field of hydrology, the chemical and physical properties of water, its relationship with the environment and its relationship with living beings are evaluated.

Hydrology as a science has a complex nature, so its study has been divided into various fields. This division contemplates various aspects that focus on some of the phases of the hydrological cycle: the dynamics of the oceans (oceanography), lakes (limnology) and rivers (potamology), surface waters, hydrometeorology, hydrogeology (groundwater) and cryology (solid water).

Quelccaya Glacier (Peru). Source: Edubucher, from Wikimedia Commons

Recent Research Examples

Research in hydrology in recent years has focused mainly on the application of simulation models, 3D geological models and artificial neural networks.

Surface water hydrology

In the field of surface water hydrology, artificial neural network models are being applied to study the dynamics of hydrographic basins. Thus, the SIATL (Watershed Water Flow Simulator) project is being used worldwide for watershed management.

Computer programs such as WEAP (Water Evaluation and Planning), developed in Sweden and offered free of charge as a comprehensive tool for planning the management of water resources, have also been developed.

Hydrogeology

In this field, 3D geological models have been designed that allow creating three-dimensional maps of underground water reserves.

In a study carried out by Gámez and collaborators in the delta of the Llobregat river (Spain) the present aquifers could be located. In this way, the water sources of this important basin that supplies the city of Barcelona were registered.

Cryology

Cryology is a field that has taken a great boom in recent years, mainly due to the study of glaciers. In this sense, it has been observed that the world's glaciers are being seriously affected by global warming.

Therefore, simulation models are being designed to estimate the future loss behavior of glaciers.

Castillo, in 2015, evaluated the glaciers of the Maipo basin, finding that the glacial surface has retreated 127.9 km ², a retreat that has occurred in the last 30 years and corresponds to 25% of the initial surface of the glacier.

In the Andes, Bijeesh-Kozhikkodan et al. (2016) conducted an evaluation of the glacier surface during the years 1975 to 2015. They found that during this period there was a significant reduction in these frozen water masses.

The main reduction of the Andean glacial surface was observed between 1975 and 1997, coinciding with the warming of the Pacific Ocean.

References

1. ASCE Task Committee on Application of Artificial Neural Networks in Hydrology (2000) Artificial Neural Networks in Hydrology. I: Preliminary Concepts. Journal of Hydrologic Engineering 5: 115–123.
2. Campos DF (1998) Processes of the hydrological cycle. Third reprint. Autonomous University of San Luis Potosí, Faculty of Engineering. Editorial Universitaria Potosina. San Luis Potosí, Mexico. 540 pp.
3. Bijeesh-Kozhikkodan V, SF Ruiz-Pereira, W Shanshan, P Teixeira-Valente, AE Bica-Grondona, AC Becerra Rondón, IC Rekowsky, S Florêncio de Souza, N Bianchini, U Franz-Bremer, J Cardia-Simões. (2016). A comparative analysis of glacial retreat in the Tropical Andes using remote sensing Investig. Geogr. Chile, 51: 3-36.
4. Castillo Y (2015) Characterization of the glacial hydrology of the Maipo River basin through the implementation of a physically based semi-distributed glacio-hydrological model. Master's Thesis in Engineering Sciences, Mention in Water Resources and Environment. Universidad de Chile, Faculty of Physical and Mathematical Sciences, Department of Civil Engineering.
5. Koren V, S Reed, M Smith, Z Zhang and DJ Seo (2004) Hydrology laboratory research modeling system (HL-RMS) of the US National Weather Service. Journal of Hydrology 291: 297-318.
6. Underground Hydrology Group (GHS), CSIC - Spain. https://h2ogeo.upc.edu/es/ Revised January 27, 2019.