Which term refers to the study of water as it moves on, under, and through the Earth's surface?

The term that refers to the study of water as it moves on, under, and through the Earth's surface is hydrology. This field encompasses the analysis of the water cycle, the distribution and movement of freshwater resources, and the behavior of water in the atmosphere, on land, and underground. Hydrology plays a critical role in understanding weather patterns, climate change impacts, water resource management, and ecosystems.

Hydrography, while related, specifically focuses on the measurement and description of physical features in bodies of water and the mapping of these areas, rather than the movement of water across the surface and underground. Hydraulics deals more with the mechanical properties of fluids (liquids and gases), particularly in engineering and construction applications, rather than the broader study of water cycles and distribution. Fluvial geomorphology examines landforms created by river processes but is a subset of hydrology rather than a term that encompasses the overall study of water movement.