Hydraulic tomography is a geophysical imaging technique used to characterize subsurface properties related to groundwater flow and contaminant transport. It involves injecting water or a tracer at multiple points into the subsurface and monitoring the response at observation points to infer the distribution of hydraulic properties, such as permeability and porosity. By analyzing the data collected from these injections and monitoring points, researchers can create a three-dimensional image of the subsurface properties and identify potential pathways for groundwater flow or contaminant migration. This information can be valuable for environmental remediation, water resource management, and understanding the behavior of subsurface fluids.