hydrology

American  

[hahy-drol-uh-jee] / haɪˈdrɒl ə dʒi /

noun

1. the science dealing with the occurrence, circulation, distribution, and properties of the waters of the earth and its atmosphere.

2. hydrogeology; geohydrology.

---

hydrology British  

/ ˌhaɪdrəˈlɒdʒɪk, haɪˈdrɒlədʒɪ /

noun

1. the study of the distribution, conservation, use, etc, of the water of the earth and its atmosphere, particularly at the land surface

---

hydrology Scientific  

/ hī-drŏl′ə-jē /

1. The scientific study of the properties, distribution, and effects of water as a liquid, solid, or gas on the Earth's surface, in the soil and underlying rocks, and in the atmosphere.

---

Other Word Forms

• hydrologic adjective
• hydrological adjective
• hydrologically adverb
• hydrologist noun

Etymology

Origin of hydrology

First recorded in 1755–65; hydro- ¹ + -logy

Explanation

Hydrology is the science that has to do with water on our planet and in the atmosphere, including how water moves, where it exists, and its specific properties. Hydrology is a branch of geology, the study of the earth that focuses specifically on the planet's water systems. This scientific specialization involves analysis of our water's quantity, quality, and location based on the water cycle. Scientists who study hydrology are known as hydrologists, and their work includes testing water samples for contamination, predicting floods and droughts, and making sure our drinking water is clean. The word hydrology comes from the Greek roots hydro-, meaning "water," and -logy, meaning "study of."

Example Sentences

It is important to note, though, that many other factors affect the risk of flooding including land use, groundwater extraction, local hydrology and preceding conditions.

From BBC • Feb. 18, 2026

"This is one of those worst-case scenarios that you prepare for but desperately hope never happen," says Hannah Cloke, professor of hydrology at the University of Reading.

From BBC • Oct. 28, 2025

The UFZ researchers operate over a wide range of disciplines from hydrology, toxicology, microbiology and environmental chemistry to social sciences and are part of the UFZ's Microplastics Competence Cluster.

From Science Daily • Nov. 21, 2024

The air will be filled with dust while patterns for hydrology and drainage will be altered, perhaps with unanticipated consequences.

From Salon • Sep. 19, 2024

This is evidenced by the inclusion of geologic discussions in most textbooks of hydrology, and in the reports of the Hydrographic Branch of the U. S. Geological Survey.

From The Economic Aspect of Geology by Leith, C. K. (Charles Kenneth)