Which rock properties determine permeability to groundwater flow?

In hydrologic sciences, the permeability of a rock—its capacity to transmit fluids like groundwater—is primarily determined by the characteristics of its void spaces and the arrangement of its constituent materials.12

Key properties influencing permeability include:

• Pore Size and Shape: Permeability is largely dependent on the size and shape of the pores within the rock. Larger, interconnected pores facilitate easier fluid transport, whereas smaller pores restrict movement.12
• Grain Characteristics: In granular materials such as sedimentary rocks, permeability is determined by the size, shape, and packing arrangement of the grains.13
• Interconnectivity: For fluid to flow, pores must be interconnected. While total porosity measures all void space, effective (or net) porosity—the proportion of interconnected pores accessible to the surface—is the critical factor for the movement of groundwater.4
• Sorting and Compaction: The degree of sorting (the uniformity of grain sizes) and the level of compaction affect the distribution and size of pore spaces.4
• Cementation: The presence of natural cementing materials can seal off pores, reducing the rock's ability to transmit fluids.4