Subsurface hydrology is a branch of hydrology that focuses on the study of water movement, storage, and distribution in the subsurface layers of the Earth. This includes the study of groundwater flow, aquifers, soil moisture, and the interactions between surface water and groundwater. Subsurface hydrology is important for understanding water availability, contamination, and groundwater recharge processes, and plays a crucial role in managing water resources and addressing issues such as groundwater depletion and pollution. Researchers in this field use a variety of techniques, such as computer modeling, field measurements, and remote sensing, to study the complex dynamics of water movement beneath the Earth's surface.