Britannica
Sources used in this answer
What do hydrologists study about water on and below Earth’s surface?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Earth sciences
Geologist using a rock hammer to sample active pahoehoe lava for geochemical analysis on the Kilauea volcano, Hawaii, June 26, 2009.
Hydrology is the scientific discipline focused on the occurrence, distribution, and circulation of water on and below Earth’s surface, as well as its physical and chemical properties and interactions with living things.1
Hydrologists primarily study the components of the hydrologic cycle that occur near the land surface, including:
- Surface Water: Researchers measure precipitation and streamflow (hydrometry), describe and map large bodies of water like lakes and oceans (hydrography), and analyze the mechanics of water in its liquid state (hydraulics).
- Subsurface Water: Specialists examine water in the saturated zone (groundwater hydrology) and water within the unsaturated zone (soil-water physics). This includes studying aquifers, groundwater recharge, and the movement of pollutants through rock and soil.123
- Atmospheric Interactions: Hydrometeorology focuses on water within the lower boundary layer of the atmosphere.13
Underlying these studies is the concept of the water balance, which applies the principle of conservation of mass to evaluate how water is stored and moves through a specific area or catchment.3