Subsurface heterogeneity refers to the variation in physical and chemical properties of subsurface materials, such as soil, rock, and groundwater, across a given area. This variation can affect the movement of fluids, such as water, contaminants, or nutrients, through the subsurface, and can impact the distribution of plant roots and other organisms. Researchers studying subsurface heterogeneity aim to characterize and understand the spatial distribution of different properties, such as porosity, permeability, and mineral composition, in order to improve the accuracy of models used for predicting subsurface processes. This research is important for a wide range of applications, including groundwater management, environmental remediation, and geotechnical engineering.