What type of porosity does fractured rock have?

Fractured rock typically exhibits variable porosity due to the presence of cracks, fissures, and voids that create pathways for fluids while also maintaining solid rock mass in between these voids. The porosity in fractured rock does not conform to a single category like low, medium, or high because it can range widely depending on the degree and frequency of the fractures as well as the physical characteristics of the surrounding rock matrix. In many cases, while the fractures may allow for significant fluid movement, the overall volume of void space can still be quite varied. This variability is essential to understanding how groundwater interacts with fractured rock systems, affecting both water availability and the efficiency of onsite sewage facilities.

Thus, while some may describe fractured rock as having high porosity in certain contexts, it is more accurate to characterize it as having variable porosity to account for the complexities introduced by the fracture network. Understanding this variability is crucial for making informed decisions in the installation and management of onsite sewage facilities, as it will influence the effectiveness of wastewater treatment and groundwater protection.