Definition: Hydrology and Hydraulics

Hydrology is the study of the distribution and movement of water on the Earth’s surface and in the subsurface. Hydrologists use mathematical models to simulate the hydrologic cycle, which includes precipitation, infiltration, runoff, evapotranspiration, and groundwater flow. These models can be used to predict the amount of water that will be available for human use, to assess the risk of flooding and droughts, and to design water management systems.

Closely related to this is hydraulics. This is the study of the flow of fluids, including water. Hydraulics engineers use mathematical models to simulate the flow of water in rivers, streams, canals, and pipes. These models can be used to design bridges, dams, and other water infrastructure, to assess the risk of floods and erosion, and to manage water resources.

Hydrologic and hydraulic modeling are often used together to understand and manage water resources. For example, a hydrologic model can be used to predict the amount of water that will be available for a city, and a hydraulic model can be used to design the water distribution system.