1.2 Why Should We Study Fractured Aquifers?

Crystalline and other low primary permeability and porosity rocks occupy large areas of all continents where groundwater plays an important role in supplying populations, as well as economic activities, as discussed in Section 1.4. Thus, to determine groundwater sustainability, the production potential of these aquifers needs to be studied. In addition, the numerous cases of contamination of fractured aquifers by human activities, especially in industrial and urban areas, need to be assessed to protect public health. Understanding fracture network properties is critical for assessing and predicting contaminant transport through fractured rock aquifers. A substantial body of knowledge has been produced by Parker and collaborators (e.g., Parker et al. 2018) that reports on diffusion from fractures into the rock matrix (e.g., Wanner et al., 2018). Contaminated groundwater represents a water resource that has been lost, or is not available for most uses for a long time; preventive measures need to be taken to avoid this loss. Such needs have been exacerbated by the expansion of urban areas and polluting activities throughout regions supplied by contaminated, fractured aquifers. These anthropogenic activities considerably increase the demand for water supply, thus the motivation for studying fractured media is more pressing. Other relevant applications of fractured-aquifer knowledge are related to geotechnical engineering, mineral/oil extraction, and risk evaluation of natural disasters (e.g., landslides), as well as, over the last 40 years, disposal of radioactive waste. All these activities can cause or facilitate groundwater contamination. Geotechnical engineering works can be affected by terrain instability due to groundwater flow coupled with modifications in the landscape. Examples of fractured aquifers that face a critical situation, due to the scarcity of water supply and/or the existence of extensive cases of contamination by highly harmful substances to health, are provided in Section 1.4.