Influence of fracture truncation on dispersion: A dual permeability model

Simulations with a dual permeability model show that a few discrete fractures can have a major influence on plume geometry. A limited number of truncated fractures (1–4) within a permeable matrix can create nearly circular plumes, with about the same degree of spreading in the direction transverse to the average hydraulic gradient as in the longitudinal direction. By comparison, continuous fractures in the direction of flow tend to produce elongated plumes, similar to those typically seen in granular materials. Both types of plumes have been observed in tracer experiments in fractured porous media on the Oak Ridge Reservation. Understanding the influence of fracture geometry is important in planning field characterization and subsequent remediation in fractured porous media.